metronidazole/tetracycline/bismuth subsalicylate (Rx)

Duodenal Ulcer

Indicated for eradication of H pylori infection in patients with duodenal ulcer disease (active or history); use in combination with an H2 antagonist

Bismuth subsalicylate 525 mg (two 262.4 mg-chewable tablets), metronidazole 250 mg (one 250-mg tablet), and tetracycline hydrochloride 500 mg (one 500-mg capsule) PO QID for 14 days plus an H2 antagonist

Dosage Modifications

Renal impairment

• Antianabolic action of the tetracyclines may cause an increase in blood urea nitrogen (BUN)
• Severe: Contraindicated

Hepatic impairment

• Mild-to-moderate: Monitor for metronidazole-associated adverse events
• Severe: Not recommended

Dosing Considerations

Only treat indicated infections that are proven or strongly suspected to be caused by susceptible bacteria to reduce development of drug-resistant bacteria

Contraindicated

Contraindicated (3)

• acitretin

  tetracycline, acitretin. Other (see comment). Contraindicated. Comment: Both acitretin and tetracyclines can cause increased intracranial pressure.

• dichlorphenamide

  dichlorphenamide increases levels of bismuth subsalicylate by unknown mechanism. Contraindicated. Coadministration of dichlorphenamide with high-dose aspirin may increase salicylate levels. Anorexia, tachypnea, lethargy, and coma reported.

• dronabinol

  metronidazole increases toxicity of dronabinol by aldehyde dehydrogenase inhibition. Contraindicated. Dronabinol oral solution (Syndros) contains 50% (w/w) dehydrated alcohol 5.5% (w/w) propylene glycol, which can produce disulfiramlike reactions if coadministered with metronidazole. Discontinue metronidazole at least 14 days before starting dronabinol solution and do not administer metronidazole within 7 days of completing treatment with dronabinol solution.

Serious - Use Alternative (133)

• abametapir

  abametapir will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

• aluminum hydroxide

  aluminum hydroxide decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• aminolevulinic acid oral

  aminolevulinic acid oral, tetracycline. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid administering other phototoxic drugs with aminolevulinic acid oral for 24 hr during perioperative period.

• aminolevulinic acid topical

  tetracycline increases toxicity of aminolevulinic acid topical by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration of photosensitizing drugs may enhance the phototoxic reaction to photodynamic therapy with aminolevulinic acid.

• amoxicillin

  tetracycline decreases effects of amoxicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

• ampicillin

  tetracycline decreases effects of ampicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

• apalutamide

  apalutamide will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.

• atracurium

  tetracycline increases effects of atracurium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• avapritinib

  metronidazole will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of avapritinib with moderate CYP3A4 inhibitors. If unable to avoid, reduce avapritinib starting dose. See drug monograph Dosage Modifications.
  
  tetracycline will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of avapritinib with moderate CYP3A4 inhibitors. If unable to avoid, reduce avapritinib starting dose. See drug monograph Dosage Modifications.

• axitinib

  tetracycline increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with moderate CYP3A4 inhibitors, monitor closely and reduce dose if necessary .
  
  metronidazole increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with moderate CYP3A4 inhibitors, monitor closely and reduce dose if necessary .

• BCG vaccine live

  tetracycline decreases effects of BCG vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.
  
  metronidazole decreases effects of BCG vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.

• bismuth subsalicylate

  bismuth subsalicylate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• bosutinib

  metronidazole increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• bosutinib

  tetracycline increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• calcium acetate

  calcium acetate, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• calcium carbonate

  calcium carbonate, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• calcium chloride

  calcium chloride, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• calcium citrate

  calcium citrate, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• calcium gluconate

  calcium gluconate, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• carbamazepine

  carbamazepine will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• carbonyl iron

  carbonyl iron decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• cholera vaccine

  tetracycline, cholera vaccine. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid coadministration of cholera vaccine with systemic antibiotics since these agents may be active against the vaccine strain. Do not administer cholera vaccine to patients who have received oral or parenteral antibiotics within 14 days prior to vaccination.
  
  metronidazole, cholera vaccine. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid coadministration of cholera vaccine with systemic antibiotics since these agents may be active against the vaccine strain. Do not administer cholera vaccine to patients who have received oral or parenteral antibiotics within 14 days prior to vaccination.

• cisatracurium

  tetracycline increases effects of cisatracurium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• cobimetinib

  metronidazole will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concurrent short term (14 days or less) use of moderate CYP3A inhibitors is unavoidable for patients who are taking cobimetinib 60 mg, reduce the cobimetinib dose to 20 mg. After discontinuation of a moderate CYP3A inhibitor, resume cobimetinib 60 mg. Use an alternative to a moderate CYP3A inhibitor in patients who are taking a reduced dose of cobimetinib (40 or 20 mg daily).

• cobimetinib

  tetracycline will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concurrent short term (14 days or less) use of moderate CYP3A inhibitors is unavoidable for patients who are taking cobimetinib 60 mg, reduce the cobimetinib dose to 20 mg. After discontinuation of a moderate CYP3A inhibitor, resume cobimetinib 60 mg. Use an alternative to a moderate CYP3A inhibitor in patients who are taking a reduced dose of cobimetinib (40 or 20 mg daily).

• demeclocycline

  bismuth subsalicylate decreases levels of demeclocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• dicloxacillin

  tetracycline decreases effects of dicloxacillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• dihydroergotamine

  metronidazole will increase the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dihydroergotamine intranasal

  metronidazole will increase the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• disulfiram

  disulfiram increases toxicity of metronidazole by decreasing metabolism. Contraindicated. Enhanced CNS & cardiac toxicity.

• doxycycline

  bismuth subsalicylate decreases levels of doxycycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• dronedarone

  metronidazole will increase the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• elacestrant

  tetracycline will increase the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  metronidazole will increase the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• eliglustat

  tetracycline increases levels of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Moderate CYP3A4 inhibitors are not recommended with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers .
  
  metronidazole increases levels of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Moderate CYP3A4 inhibitors are not recommended with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers .

• eluxadoline

  bismuth subsalicylate, eluxadoline. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that cause constipation. Increases risk for constipation related serious adverse reactions. .

• entrectinib

  tetracycline will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of moderate CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce dose to 200 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing moderate CYP3A inhibitor for 3-5 elimination half-lives.
  
  metronidazole will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of moderate CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce dose to 200 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing moderate CYP3A inhibitor for 3-5 elimination half-lives.

• enzalutamide

  enzalutamide will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ergotamine

  metronidazole will increase the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin base

  metronidazole will increase the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  metronidazole will increase the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  metronidazole will increase the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin stearate

  metronidazole will increase the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• everolimus

  metronidazole will increase the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fentanyl

  tetracycline will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
  
  metronidazole will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl intranasal

  metronidazole will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
  
  tetracycline will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl transdermal

  tetracycline will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
  
  metronidazole will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl transmucosal

  tetracycline will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
  
  metronidazole will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• ferric maltol

  ferric maltol decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• infigratinib

  metronidazole will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ferrous fumarate

  ferrous fumarate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• ferrous gluconate

  ferrous gluconate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• ferrous sulfate

  ferrous sulfate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• fexinidazole

  fexinidazole will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.

• fosphenytoin

  fosphenytoin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• idelalisib

  idelalisib will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

• infigratinib

  tetracycline will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• irinotecan

  tetracycline will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• irinotecan liposomal

  tetracycline will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• iron dextran complex

  iron dextran complex decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• iron sucrose

  iron sucrose decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• isotretinoin

  isotretinoin, tetracycline. Mechanism: unknown. Contraindicated. Risk of pseudotumor cerebri.

• ivabradine

  tetracycline will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ivabradine with moderate CYP3A4 inhibitors.
  
  metronidazole will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ivabradine with moderate CYP3A4 inhibitors.

• ivosidenib

  ivosidenib will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternative therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

• lemborexant

  metronidazole will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lemborexant with moderate or strong CYP3A inhibitors.

• lemborexant

  tetracycline will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lemborexant with moderate or strong CYP3A inhibitors.

• lovastatin

  metronidazole will increase the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lurbinectedin

  tetracycline will increase the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  metronidazole will increase the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• magnesium chloride

  magnesium chloride decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• mebendazole

  mebendazole increases toxicity of metronidazole by Other (see comment). Avoid or Use Alternate Drug. Comment: May increase the risk for toxic epidermal necrolysis or Stevens-Johnson syndrome.

• magnesium citrate

  magnesium citrate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• magnesium hydroxide

  magnesium hydroxide decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• magnesium oxide

  magnesium oxide decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• magnesium sulfate

  magnesium sulfate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• methoxyflurane

  tetracycline, methoxyflurane. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of nephrotoxicity.

• methyl aminolevulinate

  tetracycline, methyl aminolevulinate. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Each drug may increase the photosensitizing effect of the other.

• microbiota oral

  tetracycline decreases effects of microbiota oral by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Microbiota oral contains bacterial spores. Antibacterial agents may decrease efficacy if coadministered. Complete antibiotic regimens 2-4 days before initiating microbiota oral. .

• midazolam intranasal

  metronidazole will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of moderate CYP3A4 inhibitors with midazolam intranasal causes higher midazolam systemic exposure, which may prolong sedation.
  
  tetracycline will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of moderate CYP3A4 inhibitors with midazolam intranasal causes higher midazolam systemic exposure, which may prolong sedation.

• minocycline

  bismuth subsalicylate decreases levels of minocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• mobocertinib

  tetracycline will increase the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use of moderate CYP3A4 inhibitor unavoidable, reduce mobocertinib dose by ~50% (eg, 160 to 80 mg); closely monitor QTc interval.
  
  metronidazole will increase the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use of moderate CYP3A4 inhibitor unavoidable, reduce mobocertinib dose by ~50% (eg, 160 to 80 mg); closely monitor QTc interval.

• nafcillin

  tetracycline decreases effects of nafcillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• naloxegol

  metronidazole will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministation of naloxegol with moderate CYP3A4 inhibitors is unavoidable, reduce naloxegol dose to 12.5 mg qDay

• naloxegol

  tetracycline will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministation of naloxegol with moderate CYP3A4 inhibitors is unavoidable, reduce naloxegol dose to 12.5 mg qDay

• neratinib

  tetracycline will increase the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inhibitors.
  
  metronidazole will increase the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inhibitors.

• olaparib

  tetracycline will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with moderate CYP3A inhibitors cannot be avoided, reduce olaparib dose to 200 mg (capsule) or 150 mg (tablet) PO BID. Do not substitute tablets with capsules.
  
  metronidazole will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with moderate CYP3A inhibitors cannot be avoided, reduce olaparib dose to 200 mg (capsule) or 150 mg (tablet) PO BID. Do not substitute tablets with capsules.

• omaveloxolone

  tetracycline will increase the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unavoidable, reduce omaveloxolone dose to 100 mg/day. Closely monitor for adverse effects. If adverse effects emerge, further reduce to 50 mg/day.
  
  metronidazole will increase the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unavoidable, reduce omaveloxolone dose to 100 mg/day. Closely monitor for adverse effects. If adverse effects emerge, further reduce to 50 mg/day.

• onabotulinumtoxinA

  tetracycline increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• oxytetracycline

  bismuth subsalicylate decreases levels of oxytetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• pacritinib

  metronidazole will increase the level or effect of pacritinib by affecting hepatic enzyme CYP2E1 metabolism. Avoid or Use Alternate Drug.

• oxacillin

  tetracycline decreases effects of oxacillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. bacteriostatic agents may inhibit the effects of bactericidal agents.

• pacritinib

  tetracycline will increase the level or effect of pacritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• pancuronium

  tetracycline increases effects of pancuronium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• pemigatinib

  metronidazole will increase the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pemigatinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pemigatinib dose.
  
  tetracycline will increase the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pemigatinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pemigatinib dose.

• penicillin G aqueous

  tetracycline decreases effects of penicillin G aqueous by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• pexidartinib

  metronidazole will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.

• penicillin VK

  tetracycline decreases effects of penicillin VK by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• pexidartinib

  tetracycline will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.

• phenobarbital

  phenobarbital will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• phenytoin

  phenytoin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• pimozide

  metronidazole increases levels of pimozide by decreasing metabolism. Contraindicated. Risk of QT interval prolongation.

• pivmecillinam

  tetracycline decreases effects of pivmecillinam by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• polysaccharide iron

  polysaccharide iron decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• primidone

  primidone will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• propylene glycol

  metronidazole, propylene glycol. Mechanism: decreasing metabolism. Contraindicated. Disulfiram like reaction.

• ranolazine

  metronidazole will increase the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rapacuronium

  tetracycline increases effects of rapacuronium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• rocuronium

  tetracycline increases effects of rocuronium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• rose hips

  rose hips decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• selinexor

  selinexor, metronidazole. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.

• selumetinib

  tetracycline will increase the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors cannot be avoided, reduce selumetinib dosage (refer to selumetinib monograph for further information). After discontinuation of the strong or moderate CYP3A4 inhibitor for 3 elimination half-lives, resume selumetinib dose that was taken before initiating the inhibitor.
  
  metronidazole will increase the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors cannot be avoided, reduce selumetinib dosage (refer to selumetinib monograph for further information). After discontinuation of the strong or moderate CYP3A4 inhibitor for 3 elimination half-lives, resume selumetinib dose that was taken before initiating the inhibitor.

• silodosin

  metronidazole will increase the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• siponimod

  tetracycline will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a moderate or strong CYP3A4 inhibitor PLUS a moderate or strong CYP2C9 inhibitor is not recommended.

• simvastatin

  metronidazole will increase the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• siponimod

  metronidazole will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a moderate or strong CYP3A4 inhibitor PLUS a moderate or strong CYP2C9 inhibitor is not recommended.

• sirolimus

  metronidazole will increase the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sodium bicarbonate

  sodium bicarbonate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• sodium citrate/citric acid

  sodium citrate/citric acid decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• sodium sulfate/?magnesium sulfate/potassium chloride

  sodium sulfate/?magnesium sulfate/potassium chloride decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Administer tetracyclines at least 2 hr before and no less than 6 hr after each dose to avoid chelation with magnesium. .

• sodium sulfate/potassium sulfate/magnesium sulfate

  sodium sulfate/potassium sulfate/magnesium sulfate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Administer tetracyclines at least 2 hr before and no less than 6 hr after each dose to avoid chelation with magnesium. .

• strontium ranelate

  strontium ranelate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Contraindicated. Suspend strontium ranelate during antibiotic therapy.

• succinylcholine

  tetracycline increases effects of succinylcholine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• tazemetostat

  metronidazole will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of tazemetostat with moderate CYP3A4 inhibitors. If coadministration is unavoidable, reduce tazemetostat current dose (see drug monograph Dosage Modifications).
  
  tetracycline will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of tazemetostat with moderate CYP3A4 inhibitors. If coadministration is unavoidable, reduce tazemetostat current dose (see drug monograph Dosage Modifications).

• temocillin

  tetracycline decreases effects of temocillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• tetracycline

  bismuth subsalicylate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• tolvaptan

  metronidazole will increase the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ticarcillin

  tetracycline decreases effects of ticarcillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• tretinoin

  tetracycline, tretinoin. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

• tretinoin topical

  tetracycline, tretinoin topical. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

• tripotassium dicitratobismuthate

  tripotassium dicitratobismuthate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• tucatinib

  tucatinib will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.

• typhoid vaccine live

  tetracycline decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.
  
  metronidazole decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.

• vecuronium

  tetracycline increases effects of vecuronium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• venetoclax

  metronidazole will increase the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If a moderate CYP3A inhibitor must be used, reduce the venetoclax dose by at least 50%. Monitor more closely for signs of venetoclax toxicities.

• warfarin

  bismuth subsalicylate increases effects of warfarin by anticoagulation. Avoid or Use Alternate Drug.

Monitor Closely (197)

• acalabrutinib

  tetracycline will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease acalabrutinib dose to 100 mg once daily if coadministered with a moderate CYP3A inhibitor.
  
  metronidazole will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease acalabrutinib dose to 100 mg once daily if coadministered with a moderate CYP3A inhibitor.

• acebutolol

  bismuth subsalicylate, acebutolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• almotriptan

  metronidazole will increase the level or effect of almotriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• atenolol

  bismuth subsalicylate, atenolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• atogepant

  tetracycline will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• alprazolam

  metronidazole will increase the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• amifampridine

  metronidazole increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

• amiodarone

  metronidazole will increase the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• aprepitant

  metronidazole will increase the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• aripiprazole

  metronidazole will increase the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• artemether/lumefantrine

  metronidazole will increase the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• atogepant

  metronidazole will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• atorvastatin

  metronidazole will increase the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• avanafil

  tetracycline will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; increased levels may result in increased associated adverse events; the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours for patients taking concomitant moderate CYP3A4 inhibitors
  
  metronidazole will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; increased levels may result in increased associated adverse events; the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours for patients taking concomitant moderate CYP3A4 inhibitors

• bazedoxifene/conjugated estrogens

  tetracycline will decrease the level or effect of bazedoxifene/conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will decrease the level or effect of bazedoxifene/conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• benazepril

  bismuth subsalicylate decreases effects of benazepril by pharmacodynamic antagonism. Use Caution/Monitor. Salicylates may also increase nephrotoxic effects of ACE inhibitors.

• betaxolol

  bismuth subsalicylate, betaxolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• bisoprolol

  bismuth subsalicylate, bisoprolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• bortezomib

  metronidazole will increase the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bosentan

  bosentan will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• brexpiprazole

  tetracycline will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP3A4 inhibitor PLUS a strong/moderate CYP2D6 inhibitor.
  
  metronidazole will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP3A4 inhibitor PLUS a strong/moderate CYP2D6 inhibitor.

• budesonide

  metronidazole will increase the level or effect of budesonide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• buprenorphine subdermal implant

  tetracycline will increase the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inhibitors for signs and symptoms of overmedication. If the dose of the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inhibitor is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for withdrawal.

• buprenorphine subdermal implant

  metronidazole will increase the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inhibitors for signs and symptoms of overmedication. If the dose of the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inhibitor is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for withdrawal.

• buprenorphine, long-acting injection

  metronidazole will increase the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inhibitors should be monitored to ensure buprenorphine plasma levels are adequate. Within 2 weeks, if signs and symptoms of buprenorphine toxicity or overdose occur and the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.
  
  tetracycline will increase the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inhibitors should be monitored to ensure buprenorphine plasma levels are adequate. Within 2 weeks, if signs and symptoms of buprenorphine toxicity or overdose occur and the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.

• buspirone

  metronidazole will increase the level or effect of buspirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cabazitaxel

  tetracycline will increase the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A4 inhibitors.

• cabozantinib

  tetracycline will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cannabidiol

  metronidazole will increase the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a moderate CYP3A4 inhibitor.
  
  tetracycline will increase the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a moderate CYP3A4 inhibitor.

• carbamazepine

  metronidazole will increase the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• carvedilol

  bismuth subsalicylate, carvedilol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• cefdinir

  tetracycline decreases effects of cefdinir by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• carvedilol

  metronidazole will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• cefditoren

  tetracycline decreases effects of cefditoren by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• cefoxitin

  tetracycline decreases effects of cefoxitin by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• cefpodoxime

  tetracycline decreases effects of cefpodoxime by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• ceftriaxone

  tetracycline decreases effects of ceftriaxone by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• cefuroxime

  tetracycline decreases effects of cefuroxime by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• celiprolol

  bismuth subsalicylate, celiprolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• cenobamate

  cenobamate will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.

• cholestyramine

  cholestyramine decreases levels of metronidazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cholestyramine decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

• cilostazol

  metronidazole will increase the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• conjugated estrogens

  tetracycline will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• cinacalcet

  metronidazole will increase the level or effect of cinacalcet by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clopidogrel

  metronidazole will decrease the level or effect of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Inhibition of CYP3A4 will reduce clopidogrel bioactivation

• clozapine

  metronidazole will increase the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• conivaptan

  metronidazole will increase the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• conjugated estrogens

  metronidazole will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• conjugated estrogens, vaginal

  metronidazole will increase the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cortisone

  metronidazole will increase the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• crofelemer

  crofelemer increases levels of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.

• cyclosporine

  metronidazole will increase the level or effect of cyclosporine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dabrafenib

  dabrafenib will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• daridorexant

  tetracycline will increase the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Daridorexant dose should not exceed 25 mg per night when coadministered with moderate CYP3A4 inhibitors.
  
  metronidazole will increase the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Daridorexant dose should not exceed 25 mg per night when coadministered with moderate CYP3A4 inhibitors.

• darifenacin

  metronidazole will increase the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• deflazacort

  tetracycline will increase the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease deflazacort dose to one-third of the recommended dose if coadministered with moderate or strong CYP3A4 inhibitors.

• darunavir

  metronidazole will increase the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dasatinib

  metronidazole will increase the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• deflazacort

  metronidazole will increase the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease deflazacort dose to one-third of the recommended dose if coadministered with moderate or strong CYP3A4 inhibitors.

• dexamethasone

  metronidazole will increase the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• diazepam

  metronidazole will increase the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• diazepam intranasal

  tetracycline will increase the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.
  
  metronidazole will increase the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.

• didanosine

  didanosine will decrease the level or effect of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Oral tetracycline should not be administered simultaneously with didanosine (chewable tablets or powder for oral solution); use alternatives if available. Tetracycline antibiotics should be taken 1 hour before or 4 hours after administration of didanosine.

• digoxin

  metronidazole will increase the level or effect of digoxin by altering intestinal flora. Applies only to oral form of both agents. Use Caution/Monitor.

• digoxin

  tetracycline will increase the level or effect of digoxin by altering intestinal flora. Applies only to oral form of both agents. Use Caution/Monitor.

• efavirenz

  efavirenz will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• elagolix

  elagolix decreases levels of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.

• eletriptan

  metronidazole will increase the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

• encorafenib

  encorafenib, tetracycline. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.

• erlotinib

  metronidazole will increase the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• esmolol

  bismuth subsalicylate, esmolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• estradiol

  metronidazole will decrease the level or effect of estradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will decrease the level or effect of estradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• estrogens conjugated synthetic

  metronidazole will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• estropipate

  metronidazole will decrease the level or effect of estropipate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will decrease the level or effect of estropipate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• ethanol

  metronidazole, ethanol. Mechanism: decreasing metabolism. Use Caution/Monitor. Disulfiram like reaction.

• ethinylestradiol

  tetracycline will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• ethinylestradiol

  metronidazole will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• ethotoin

  metronidazole will increase the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• etonogestrel

  metronidazole will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• etravirine

  etravirine will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• fedratinib

  fedratinib will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.

• felodipine

  metronidazole will increase the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fesoterodine

  metronidazole will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• finerenone

  metronidazole will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.
  
  tetracycline will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.

• fludrocortisone

  metronidazole will increase the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ifosfamide

  tetracycline decreases effects of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of a CYP3A4 inhibitor may decrease metabolism of ifosfamide, potentially reducing ifosfamide therapeutic effects.

• fluorouracil

  metronidazole increases toxicity of fluorouracil by decreasing elimination. Use Caution/Monitor.

• fosamprenavir

  metronidazole will increase the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fosaprepitant

  metronidazole will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fosphenytoin

  metronidazole will increase the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• guanfacine

  metronidazole will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.

• hydrocortisone

  metronidazole will increase the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydroxyprogesterone caproate (DSC)

  metronidazole will increase the level or effect of hydroxyprogesterone caproate (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ibrutinib

  metronidazole increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate CYP3A4 inhibitors, reduce ibrutinib dose to 280 mg qDay (B-cell malignancies) or 420 mg qDay (graft versus host disease). After CYP3A inhibitor discontinuation, resume previous dose of ibrutinib.

• ifosfamide

  metronidazole decreases effects of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of a CYP3A4 inhibitor may decrease metabolism of ifosfamide, potentially reducing ifosfamide therapeutic effects.

• iloperidone

  metronidazole will increase the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  iloperidone increases levels of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.

• indinavir

  metronidazole will increase the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isavuconazonium sulfate

  tetracycline will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isavuconazonium sulfate

  metronidazole will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isoniazid

  metronidazole will increase the level or effect of isoniazid by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

• istradefylline

  istradefylline will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.

• ivacaftor

  metronidazole increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce ivacaftor dose if coadministered with moderate CYP3A4 inhibitors. See specific ivacaftor-containing product for precise dosage modification.

• ivosidenib

  tetracycline will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with moderate CYP3A4 inhibitors may increase ivosidenib plasma concentrations, thus increasing the risk of QTc prolongation. Monitor for increased risk of QTc interval prolongation.
  
  metronidazole will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with moderate CYP3A4 inhibitors may increase ivosidenib plasma concentrations, thus increasing the risk of QTc prolongation. Monitor for increased risk of QTc interval prolongation.

• ixabepilone

  metronidazole will increase the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• labetalol

  bismuth subsalicylate, labetalol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• lanthanum carbonate

  lanthanum carbonate decreases levels of tetracycline by cation binding in GI tract. Use Caution/Monitor. Administer oral tetracycline antibiotics at least 2 hr before or after lanthanum. Interaction applies only to oral tetracyclines.

• lapatinib

  metronidazole will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lefamulin

  metronidazole will increase the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for adverse effects if lefamulin is coadministered with moderate CYP3A inhibitors.
  
  tetracycline will increase the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for adverse effects if lefamulin is coadministered with moderate CYP3A inhibitors.

• lenacapavir

  lenacapavir will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.

• levamlodipine

  metronidazole will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate and strong CYP3A inhibitors results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is coadministered with CYP3A inhibitors to determine the need for dose adjustment.

• levamlodipine

  tetracycline will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate and strong CYP3A inhibitors results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is coadministered with CYP3A inhibitors to determine the need for dose adjustment.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  metronidazole will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.
  
  tetracycline will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.

• lopinavir

  metronidazole will increase the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lorlatinib

  lorlatinib will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• loratadine

  metronidazole will increase the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• losartan

  metronidazole will increase the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.

• lumateperone

  tetracycline will increase the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce lumateperone dose to 21 mg/day if coadministered with moderate CYP3A4 inhibitors.
  
  metronidazole will increase the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce lumateperone dose to 21 mg/day if coadministered with moderate CYP3A4 inhibitors.

• lumefantrine

  metronidazole will increase the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• magnesium supplement

  magnesium supplement will decrease the level or effect of tetracycline by Other (see comment). Modify Therapy/Monitor Closely. Formation of an insoluble complex reduces absorption of the drug through intestinal tract; administer magnesium 2hr before the tetracycline or 4hr after the tetracycline

• maraviroc

  metronidazole will increase the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mavacamten

  metronidazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.
  
  tetracycline will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• mefloquine

  tetracycline will increase the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mestranol

  metronidazole will decrease the level or effect of mestranol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will decrease the level or effect of mestranol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• methadone

  metronidazole will increase the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• methotrexate

  tetracycline increases levels of methotrexate by decreasing elimination. Use Caution/Monitor. If tetracyclines cannot be avoided in patients receiving high-dose methotrexate, closely monitor methotrexate plasma concentrations and patients for signs and symptoms of toxicity.

• methoxsalen

  methoxsalen, tetracycline. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive photosensitizing effects.

• methylprednisolone

  metronidazole will increase the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• metoclopramide intranasal

  bismuth subsalicylate will decrease the level or effect of metoclopramide intranasal by Other (see comment). Use Caution/Monitor. Coadministration of metoclopramide intranasal with drugs that impair GI motility may decrease systemic absorption of metoclopramide. Monitor for reduced therapeutic effect.

• metoprolol

  bismuth subsalicylate, metoprolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• midazolam

  metronidazole will increase the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mipomersen

  mipomersen, tetracycline. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

• mitotane

  mitotane decreases levels of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.

• nadolol

  bismuth subsalicylate, nadolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• nafcillin

  nafcillin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• naldemedine

  tetracycline increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.
  
  metronidazole increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.

• nateglinide

  metronidazole will increase the level or effect of nateglinide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• nebivolol

  bismuth subsalicylate, nebivolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• oliceridine

  tetracycline will increase the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.

• nelfinavir

  metronidazole will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nicardipine

  metronidazole will increase the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nilotinib

  metronidazole will increase the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nisoldipine

  metronidazole will increase the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oliceridine

  metronidazole will increase the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.

• omadacycline

  bismuth subsalicylate will decrease the level or effect of omadacycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.

• palbociclib

  metronidazole will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• parecoxib

  metronidazole will increase the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• penbutolol

  bismuth subsalicylate, penbutolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• pindolol

  bismuth subsalicylate, pindolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• piperacillin

  tetracycline decreases effects of piperacillin by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• pazopanib

  metronidazole will increase the level or effect of pazopanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of pazopanib with strong CYP3A4 inhibitors if possible; if must coadminister, decrease pazopanib dose to 400 mg/day

• phenytoin

  metronidazole will increase the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• polycarbophil

  polycarbophil decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

• porfimer

  tetracycline, porfimer. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Enhanced photosensitivity.

• prednisone

  metronidazole will increase the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• propranolol

  bismuth subsalicylate, propranolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• quetiapine

  metronidazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• quinidine

  metronidazole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• repaglinide

  metronidazole will increase the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rifabutin

  rifabutin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rifampin

  rifampin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rifapentine

  rifapentine will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rimegepant

  tetracycline will increase the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid repeating rimegepant dose within 48 hr if coadministered with a moderate CYP3A4 inhibitor.
  
  metronidazole will increase the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid repeating rimegepant dose within 48 hr if coadministered with a moderate CYP3A4 inhibitor.

• ritonavir

  metronidazole will increase the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rucaparib

  rucaparib will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.

• ruxolitinib

  tetracycline will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ruxolitinib topical

  tetracycline will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• saquinavir

  metronidazole will increase the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sarecycline

  bismuth subsalicylate will decrease the level or effect of sarecycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.

• sodium picosulfate/magnesium oxide/anhydrous citric acid

  tetracycline decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.
  
  sodium picosulfate/magnesium oxide/anhydrous citric acid decreases levels of tetracycline by cation binding in GI tract. Use Caution/Monitor. Take at least 2 hours before and not less than 6 hours after administration of sodium picosulfate, magnesium oxide and anhydrous citric acid to avoid magnesium chelation.

• sodium picosulfate/magnesium oxide/anhydrous citric acid

  metronidazole decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.

• solifenacin

  metronidazole will increase the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sonidegib

  tetracycline will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of sonidegib with moderate CYP3A4 inhibitors. If a moderate CYP3A inhibitor must be used, administer the moderate CYP3A inhibitor for <14 days and monitor closely for adverse reactions, particularly musculoskeletal adverse reactions.
  
  metronidazole will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of sonidegib with moderate CYP3A4 inhibitors. If a moderate CYP3A inhibitor must be used, administer the moderate CYP3A inhibitor for <14 days and monitor closely for adverse reactions, particularly musculoskeletal adverse reactions.

• sotalol

  bismuth subsalicylate, sotalol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• sparsentan

  tetracycline will increase the level or effect of sparsentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No dosage adjustment needed. Monitor blood pressure, serum potassium, edema, and kidney function regularly if sparsentan is coadministered with moderate CYP3A4 inhibitors.
  
  metronidazole will increase the level or effect of sparsentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No dosage adjustment needed. Monitor blood pressure, serum potassium, edema, and kidney function regularly if sparsentan is coadministered with moderate CYP3A4 inhibitors.

• stiripentol

  stiripentol, tetracycline. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.

• sufentanil SL

  metronidazole will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.

• sufentanil SL

  tetracycline will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.

• sulfamethoxazole

  metronidazole, sulfamethoxazole. Mechanism: decreasing metabolism. Use Caution/Monitor. Disulfiram like reaction.

• sunitinib

  metronidazole will increase the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• suvorexant

  tetracycline will increase the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease suvorexant starting dose to 5 mg HS if coadministered with moderate CYP3A4 inhibitors
  
  metronidazole will increase the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease suvorexant starting dose to 5 mg HS if coadministered with moderate CYP3A4 inhibitors

• tacrolimus

  metronidazole will increase the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tadalafil

  tetracycline will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce tadalafil clearance increasing systemic exposure to tadalafil; increased levels may result in increased associated adverse events.

• tadalafil

  metronidazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tamoxifen

  metronidazole, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).

• tamsulosin

  metronidazole increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.

• tazemetostat

  tazemetostat will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tecovirimat

  tecovirimat will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

• temsirolimus

  metronidazole will increase the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tezacaftor

  metronidazole will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tezacaftor dosage regimen if coadministered with a moderate CYP3A inhibitor.
  
  tetracycline will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tezacaftor dosage regimen if coadministered with a moderate CYP3A inhibitor.

• theophylline

  metronidazole will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• timolol

  bismuth subsalicylate, timolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• tinidazole

  tetracycline will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tinidazole

  metronidazole will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tipranavir

  metronidazole will increase the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tobramycin inhaled

  tobramycin inhaled and bismuth subsalicylate both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicity

• tofacitinib

  tetracycline increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No specific dose adjustment recommended when tofacitinib coadministered with moderate CYP3A4 inhibitors; decrease tofacitinib dose if coadministered with both moderate CYP3A4 and potent CYP2C19 inhibitors .
  
  metronidazole increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No specific dose adjustment recommended when tofacitinib coadministered with moderate CYP3A4 inhibitors; decrease tofacitinib dose if coadministered with both moderate CYP3A4 and potent CYP2C19 inhibitors.

Minor (72)

• acetaminophen

  metronidazole will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

• acetaminophen IV

  metronidazole will increase the level or effect of acetaminophen IV by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

• acetaminophen rectal

  metronidazole will increase the level or effect of acetaminophen rectal by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

• acetazolamide

  acetazolamide will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• alfentanil

  metronidazole will increase the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• alfuzosin

  metronidazole will increase the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• alosetron

  metronidazole will increase the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
  
  metronidazole will increase the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• amitriptyline

  metronidazole will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• anastrozole

  anastrozole will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• antithrombin alfa

  tetracycline increases effects of antithrombin alfa by pharmacodynamic synergism. Minor/Significance Unknown.

• antithrombin III

  tetracycline increases effects of antithrombin III by pharmacodynamic synergism. Minor/Significance Unknown.

• argatroban

  tetracycline increases effects of argatroban by pharmacodynamic synergism. Minor/Significance Unknown.

• armodafinil

  metronidazole will increase the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• aspirin

  bismuth subsalicylate increases effects of aspirin by pharmacodynamic synergism. Minor/Significance Unknown.

• aspirin rectal

  bismuth subsalicylate increases effects of aspirin rectal by pharmacodynamic synergism. Minor/Significance Unknown.

• aspirin/citric acid/sodium bicarbonate

  bismuth subsalicylate increases effects of aspirin/citric acid/sodium bicarbonate by pharmacodynamic synergism. Minor/Significance Unknown.

• atazanavir

  metronidazole will increase the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• atovaquone

  tetracycline decreases levels of atovaquone by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Effect may be minor, due to pharmacodynamic synergism.

• balsalazide

  metronidazole will decrease the level or effect of balsalazide by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  tetracycline will decrease the level or effect of balsalazide by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• bemiparin

  tetracycline increases effects of bemiparin by pharmacodynamic synergism. Minor/Significance Unknown.

• biotin

  metronidazole will decrease the level or effect of biotin by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• biotin

  tetracycline will decrease the level or effect of biotin by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• bivalirudin

  tetracycline increases effects of bivalirudin by pharmacodynamic synergism. Minor/Significance Unknown.

• bosentan

  metronidazole will increase the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
  
  metronidazole will increase the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• celecoxib

  metronidazole will increase the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• cevimeline

  metronidazole will increase the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• clarithromycin

  metronidazole will increase the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• clomipramine

  metronidazole will increase the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• colestipol

  colestipol decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• cyclophosphamide

  cyclophosphamide will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• dalteparin

  tetracycline increases effects of dalteparin by pharmacodynamic synergism. Minor/Significance Unknown.

• dapsone

  metronidazole will increase the level or effect of dapsone by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.
  
  metronidazole will increase the level or effect of dapsone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• diclofenac

  metronidazole will increase the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• didanosine

  didanosine, metronidazole. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Enhanced risk of peripheral neuropathy.

• disopyramide

  metronidazole will increase the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• docetaxel

  metronidazole will increase the level or effect of docetaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• donepezil

  metronidazole will increase the level or effect of donepezil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• dutasteride

  metronidazole will increase the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• efavirenz

  metronidazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• enoxaparin

  tetracycline increases effects of enoxaparin by pharmacodynamic synergism. Minor/Significance Unknown.

• eplerenone

  metronidazole will increase the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• esomeprazole

  esomeprazole increases levels of bismuth subsalicylate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• estradiol vaginal

  tetracycline will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  metronidazole will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ethanol

  metronidazole will increase the level or effect of ethanol by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

• fondaparinux

  tetracycline increases effects of fondaparinux by pharmacodynamic synergism. Minor/Significance Unknown.

• eucalyptus

  metronidazole will increase the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• finasteride

  metronidazole will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• flurbiprofen

  metronidazole will increase the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• fluvastatin

  metronidazole will increase the level or effect of fluvastatin by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• galantamine

  metronidazole will increase the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• heparin

  tetracycline increases effects of heparin by pharmacodynamic synergism. Minor/Significance Unknown.

• ibuprofen

  metronidazole will increase the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• ibuprofen IV

  metronidazole will increase the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• imatinib

  metronidazole will increase the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• imipramine

  metronidazole will increase the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• irinotecan

  metronidazole will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• irinotecan liposomal

  metronidazole will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• isradipine

  metronidazole will increase the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• itraconazole

  metronidazole will increase the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ketoconazole

  metronidazole will increase the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• larotrectinib

  larotrectinib will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• levoketoconazole

  metronidazole will increase the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  levoketoconazole will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lithium

  metronidazole increases levels of lithium by decreasing metabolism. Minor/Significance Unknown.

• niacin

  tetracycline will decrease the level or effect of niacin by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• meloxicam

  metronidazole will increase the level or effect of meloxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• montelukast

  metronidazole will increase the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nifedipine

  metronidazole will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nimodipine

  metronidazole will increase the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nitrendipine

  metronidazole will increase the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nitroglycerin IV

  nitroglycerin IV, metronidazole. Mechanism: decreasing metabolism. Minor/Significance Unknown. Disulfiram like reaction.

• omeprazole

  omeprazole increases levels of bismuth subsalicylate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• oxybutynin

  metronidazole will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• abametapir

  Serious - Use Alternative (1)abametapir will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

• acalabrutinib

  Monitor Closely (2)tetracycline will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease acalabrutinib dose to 100 mg once daily if coadministered with a moderate CYP3A inhibitor.
  
  metronidazole will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease acalabrutinib dose to 100 mg once daily if coadministered with a moderate CYP3A inhibitor.

• acebutolol

  Monitor Closely (1)bismuth subsalicylate, acebutolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• acetaminophen

  Minor (1)metronidazole will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

• acetaminophen IV

  Minor (1)metronidazole will increase the level or effect of acetaminophen IV by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

• acetaminophen rectal

  Minor (1)metronidazole will increase the level or effect of acetaminophen rectal by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

• acetazolamide

  Minor (1)acetazolamide will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• acitretin

  Contraindicated (1)tetracycline, acitretin. Other (see comment). Contraindicated. Comment: Both acitretin and tetracyclines can cause increased intracranial pressure.

• alfentanil

  Minor (1)metronidazole will increase the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• alfuzosin

  Minor (1)metronidazole will increase the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• almotriptan

  Monitor Closely (1)metronidazole will increase the level or effect of almotriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• alosetron

  Minor (2)metronidazole will increase the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
  
  metronidazole will increase the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• alprazolam

  Monitor Closely (1)metronidazole will increase the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• aluminum hydroxide

  Serious - Use Alternative (1)aluminum hydroxide decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• amifampridine

  Monitor Closely (1)metronidazole increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

• aminolevulinic acid oral

  Serious - Use Alternative (1)aminolevulinic acid oral, tetracycline. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid administering other phototoxic drugs with aminolevulinic acid oral for 24 hr during perioperative period.

• aminolevulinic acid topical

  Serious - Use Alternative (1)tetracycline increases toxicity of aminolevulinic acid topical by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration of photosensitizing drugs may enhance the phototoxic reaction to photodynamic therapy with aminolevulinic acid.

• amiodarone

  Monitor Closely (1)metronidazole will increase the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• amitriptyline

  Minor (1)metronidazole will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• amoxicillin

  Serious - Use Alternative (1)tetracycline decreases effects of amoxicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

• ampicillin

  Serious - Use Alternative (1)tetracycline decreases effects of ampicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

• anastrozole

  Minor (1)anastrozole will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• antithrombin alfa

  Minor (1)tetracycline increases effects of antithrombin alfa by pharmacodynamic synergism. Minor/Significance Unknown.

• antithrombin III

  Minor (1)tetracycline increases effects of antithrombin III by pharmacodynamic synergism. Minor/Significance Unknown.

• apalutamide

  Serious - Use Alternative (1)apalutamide will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.

• aprepitant

  Monitor Closely (1)metronidazole will increase the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• argatroban

  Minor (1)tetracycline increases effects of argatroban by pharmacodynamic synergism. Minor/Significance Unknown.

• aripiprazole

  Monitor Closely (1)metronidazole will increase the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• armodafinil

  Minor (1)metronidazole will increase the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• artemether/lumefantrine

  Monitor Closely (1)metronidazole will increase the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• aspirin

  Minor (1)bismuth subsalicylate increases effects of aspirin by pharmacodynamic synergism. Minor/Significance Unknown.

• aspirin rectal

  Minor (1)bismuth subsalicylate increases effects of aspirin rectal by pharmacodynamic synergism. Minor/Significance Unknown.

• aspirin/citric acid/sodium bicarbonate

  Minor (1)bismuth subsalicylate increases effects of aspirin/citric acid/sodium bicarbonate by pharmacodynamic synergism. Minor/Significance Unknown.

• atazanavir

  Minor (1)metronidazole will increase the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• atenolol

  Monitor Closely (1)bismuth subsalicylate, atenolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• atogepant

  Monitor Closely (2)tetracycline will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• atorvastatin

  Monitor Closely (1)metronidazole will increase the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• atovaquone

  Minor (1)tetracycline decreases levels of atovaquone by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Effect may be minor, due to pharmacodynamic synergism.

• atracurium

  Serious - Use Alternative (1)tetracycline increases effects of atracurium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• avanafil

  Monitor Closely (2)tetracycline will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; increased levels may result in increased associated adverse events; the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours for patients taking concomitant moderate CYP3A4 inhibitors
  
  metronidazole will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; increased levels may result in increased associated adverse events; the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours for patients taking concomitant moderate CYP3A4 inhibitors

• avapritinib

  Serious - Use Alternative (2)metronidazole will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of avapritinib with moderate CYP3A4 inhibitors. If unable to avoid, reduce avapritinib starting dose. See drug monograph Dosage Modifications.
  
  tetracycline will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of avapritinib with moderate CYP3A4 inhibitors. If unable to avoid, reduce avapritinib starting dose. See drug monograph Dosage Modifications.

• axitinib

  Serious - Use Alternative (2)tetracycline increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with moderate CYP3A4 inhibitors, monitor closely and reduce dose if necessary .
  
  metronidazole increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with moderate CYP3A4 inhibitors, monitor closely and reduce dose if necessary .

• balsalazide

  Minor (2)metronidazole will decrease the level or effect of balsalazide by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  tetracycline will decrease the level or effect of balsalazide by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• bazedoxifene/conjugated estrogens

  Monitor Closely (3)tetracycline will decrease the level or effect of bazedoxifene/conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will decrease the level or effect of bazedoxifene/conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• BCG vaccine live

  Serious - Use Alternative (2)tetracycline decreases effects of BCG vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.
  
  metronidazole decreases effects of BCG vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.

• bemiparin

  Minor (1)tetracycline increases effects of bemiparin by pharmacodynamic synergism. Minor/Significance Unknown.

• benazepril

  Monitor Closely (1)bismuth subsalicylate decreases effects of benazepril by pharmacodynamic antagonism. Use Caution/Monitor. Salicylates may also increase nephrotoxic effects of ACE inhibitors.

• betaxolol

  Monitor Closely (1)bismuth subsalicylate, betaxolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• biotin

  Minor (2)metronidazole will decrease the level or effect of biotin by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  tetracycline will decrease the level or effect of biotin by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• bismuth subsalicylate

  Serious - Use Alternative (1)bismuth subsalicylate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• bisoprolol

  Monitor Closely (1)bismuth subsalicylate, bisoprolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• bivalirudin

  Minor (1)tetracycline increases effects of bivalirudin by pharmacodynamic synergism. Minor/Significance Unknown.

• bortezomib

  Monitor Closely (1)metronidazole will increase the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bosentan

  Monitor Closely (1)bosentan will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (2)metronidazole will increase the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  metronidazole will increase the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• bosutinib

  Serious - Use Alternative (2)tetracycline increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  metronidazole increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• brexpiprazole

  Monitor Closely (2)tetracycline will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP3A4 inhibitor PLUS a strong/moderate CYP2D6 inhibitor.
  
  metronidazole will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP3A4 inhibitor PLUS a strong/moderate CYP2D6 inhibitor.

• budesonide

  Monitor Closely (1)metronidazole will increase the level or effect of budesonide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• buprenorphine subdermal implant

  Monitor Closely (2)metronidazole will increase the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inhibitors for signs and symptoms of overmedication. If the dose of the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inhibitor is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for withdrawal.
  
  tetracycline will increase the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inhibitors for signs and symptoms of overmedication. If the dose of the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inhibitor is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for withdrawal.

• buprenorphine, long-acting injection

  Monitor Closely (2)metronidazole will increase the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inhibitors should be monitored to ensure buprenorphine plasma levels are adequate. Within 2 weeks, if signs and symptoms of buprenorphine toxicity or overdose occur and the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.
  
  tetracycline will increase the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inhibitors should be monitored to ensure buprenorphine plasma levels are adequate. Within 2 weeks, if signs and symptoms of buprenorphine toxicity or overdose occur and the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.

• buspirone

  Monitor Closely (1)metronidazole will increase the level or effect of buspirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cabazitaxel

  Monitor Closely (1)tetracycline will increase the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A4 inhibitors.

• cabozantinib

  Monitor Closely (2)tetracycline will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• calcium acetate

  Serious - Use Alternative (1)calcium acetate, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• calcium carbonate

  Serious - Use Alternative (1)calcium carbonate, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• calcium chloride

  Serious - Use Alternative (1)calcium chloride, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• calcium citrate

  Serious - Use Alternative (1)calcium citrate, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• calcium gluconate

  Serious - Use Alternative (1)calcium gluconate, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• cannabidiol

  Monitor Closely (2)metronidazole will increase the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a moderate CYP3A4 inhibitor.
  
  tetracycline will increase the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a moderate CYP3A4 inhibitor.

• carbamazepine

  Monitor Closely (1)metronidazole will increase the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)carbamazepine will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• carbonyl iron

  Serious - Use Alternative (1)carbonyl iron decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• carvedilol

  Monitor Closely (2)metronidazole will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  bismuth subsalicylate, carvedilol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• cefdinir

  Monitor Closely (1)tetracycline decreases effects of cefdinir by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• cefditoren

  Monitor Closely (1)tetracycline decreases effects of cefditoren by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• cefoxitin

  Monitor Closely (1)tetracycline decreases effects of cefoxitin by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• cefpodoxime

  Monitor Closely (1)tetracycline decreases effects of cefpodoxime by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• ceftriaxone

  Monitor Closely (1)tetracycline decreases effects of ceftriaxone by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• cefuroxime

  Monitor Closely (1)tetracycline decreases effects of cefuroxime by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• celecoxib

  Minor (1)metronidazole will increase the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• celiprolol

  Monitor Closely (1)bismuth subsalicylate, celiprolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• cenobamate

  Monitor Closely (1)cenobamate will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.

• cevimeline

  Minor (1)metronidazole will increase the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cholera vaccine

  Serious - Use Alternative (2)tetracycline, cholera vaccine. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid coadministration of cholera vaccine with systemic antibiotics since these agents may be active against the vaccine strain. Do not administer cholera vaccine to patients who have received oral or parenteral antibiotics within 14 days prior to vaccination.
  
  metronidazole, cholera vaccine. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid coadministration of cholera vaccine with systemic antibiotics since these agents may be active against the vaccine strain. Do not administer cholera vaccine to patients who have received oral or parenteral antibiotics within 14 days prior to vaccination.

• cholestyramine

  Monitor Closely (2)cholestyramine decreases levels of metronidazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  cholestyramine decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

• cilostazol

  Monitor Closely (1)metronidazole will increase the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cinacalcet

  Monitor Closely (1)metronidazole will increase the level or effect of cinacalcet by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cisatracurium

  Serious - Use Alternative (1)tetracycline increases effects of cisatracurium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• clarithromycin

  Minor (1)metronidazole will increase the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• clomipramine

  Minor (1)metronidazole will increase the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• clopidogrel

  Monitor Closely (1)metronidazole will decrease the level or effect of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Inhibition of CYP3A4 will reduce clopidogrel bioactivation

• clozapine

  Monitor Closely (1)metronidazole will increase the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cobimetinib

  Serious - Use Alternative (2)tetracycline will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concurrent short term (14 days or less) use of moderate CYP3A inhibitors is unavoidable for patients who are taking cobimetinib 60 mg, reduce the cobimetinib dose to 20 mg. After discontinuation of a moderate CYP3A inhibitor, resume cobimetinib 60 mg. Use an alternative to a moderate CYP3A inhibitor in patients who are taking a reduced dose of cobimetinib (40 or 20 mg daily).
  
  metronidazole will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concurrent short term (14 days or less) use of moderate CYP3A inhibitors is unavoidable for patients who are taking cobimetinib 60 mg, reduce the cobimetinib dose to 20 mg. After discontinuation of a moderate CYP3A inhibitor, resume cobimetinib 60 mg. Use an alternative to a moderate CYP3A inhibitor in patients who are taking a reduced dose of cobimetinib (40 or 20 mg daily).

• colestipol

  Minor (1)colestipol decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• conivaptan

  Monitor Closely (1)metronidazole will increase the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• conjugated estrogens

  Monitor Closely (3)metronidazole will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• conjugated estrogens, vaginal

  Monitor Closely (1)metronidazole will increase the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cortisone

  Monitor Closely (1)metronidazole will increase the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• crofelemer

  Monitor Closely (1)crofelemer increases levels of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.

• cyclophosphamide

  Minor (1)cyclophosphamide will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cyclosporine

  Monitor Closely (1)metronidazole will increase the level or effect of cyclosporine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dabrafenib

  Monitor Closely (1)dabrafenib will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• dalteparin

  Minor (1)tetracycline increases effects of dalteparin by pharmacodynamic synergism. Minor/Significance Unknown.

• dapsone

  Minor (2)metronidazole will increase the level or effect of dapsone by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.
  
  metronidazole will increase the level or effect of dapsone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• daridorexant

  Monitor Closely (2)tetracycline will increase the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Daridorexant dose should not exceed 25 mg per night when coadministered with moderate CYP3A4 inhibitors.
  
  metronidazole will increase the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Daridorexant dose should not exceed 25 mg per night when coadministered with moderate CYP3A4 inhibitors.

• darifenacin

  Monitor Closely (1)metronidazole will increase the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• darunavir

  Monitor Closely (1)metronidazole will increase the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dasatinib

  Monitor Closely (1)metronidazole will increase the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• deflazacort

  Monitor Closely (2)metronidazole will increase the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease deflazacort dose to one-third of the recommended dose if coadministered with moderate or strong CYP3A4 inhibitors.
  
  tetracycline will increase the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease deflazacort dose to one-third of the recommended dose if coadministered with moderate or strong CYP3A4 inhibitors.

• demeclocycline

  Serious - Use Alternative (1)bismuth subsalicylate decreases levels of demeclocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• dexamethasone

  Monitor Closely (1)metronidazole will increase the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• diazepam

  Monitor Closely (1)metronidazole will increase the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• diazepam intranasal

  Monitor Closely (2)tetracycline will increase the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.
  
  metronidazole will increase the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.

• dichlorphenamide

  Contraindicated (1)dichlorphenamide increases levels of bismuth subsalicylate by unknown mechanism. Contraindicated. Coadministration of dichlorphenamide with high-dose aspirin may increase salicylate levels. Anorexia, tachypnea, lethargy, and coma reported.

• diclofenac

  Minor (1)metronidazole will increase the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• dicloxacillin

  Serious - Use Alternative (1)tetracycline decreases effects of dicloxacillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• didanosine

  Monitor Closely (1)didanosine will decrease the level or effect of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Oral tetracycline should not be administered simultaneously with didanosine (chewable tablets or powder for oral solution); use alternatives if available. Tetracycline antibiotics should be taken 1 hour before or 4 hours after administration of didanosine.Minor (1)didanosine, metronidazole. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Enhanced risk of peripheral neuropathy.

• digoxin

  Monitor Closely (2)metronidazole will increase the level or effect of digoxin by altering intestinal flora. Applies only to oral form of both agents. Use Caution/Monitor.
  
  tetracycline will increase the level or effect of digoxin by altering intestinal flora. Applies only to oral form of both agents. Use Caution/Monitor.

• dihydroergotamine

  Serious - Use Alternative (1)metronidazole will increase the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dihydroergotamine intranasal

  Serious - Use Alternative (1)metronidazole will increase the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• disopyramide

  Minor (1)metronidazole will increase the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• disulfiram

  Serious - Use Alternative (1)disulfiram increases toxicity of metronidazole by decreasing metabolism. Contraindicated. Enhanced CNS & cardiac toxicity.

• docetaxel

  Minor (1)metronidazole will increase the level or effect of docetaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• donepezil

  Minor (1)metronidazole will increase the level or effect of donepezil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• doxycycline

  Serious - Use Alternative (1)bismuth subsalicylate decreases levels of doxycycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• dronabinol

  Contraindicated (1)metronidazole increases toxicity of dronabinol by aldehyde dehydrogenase inhibition. Contraindicated. Dronabinol oral solution (Syndros) contains 50% (w/w) dehydrated alcohol 5.5% (w/w) propylene glycol, which can produce disulfiramlike reactions if coadministered with metronidazole. Discontinue metronidazole at least 14 days before starting dronabinol solution and do not administer metronidazole within 7 days of completing treatment with dronabinol solution.

• dronedarone

  Serious - Use Alternative (1)metronidazole will increase the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dutasteride

  Minor (1)metronidazole will increase the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• efavirenz

  Monitor Closely (1)efavirenz will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)metronidazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• elacestrant

  Serious - Use Alternative (2)tetracycline will increase the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  metronidazole will increase the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• elagolix

  Monitor Closely (1)elagolix decreases levels of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.

• eletriptan

  Monitor Closely (1)metronidazole will increase the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• eliglustat

  Serious - Use Alternative (2)tetracycline increases levels of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Moderate CYP3A4 inhibitors are not recommended with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers .
  
  metronidazole increases levels of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Moderate CYP3A4 inhibitors are not recommended with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers .

• eluxadoline

  Serious - Use Alternative (1)bismuth subsalicylate, eluxadoline. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that cause constipation. Increases risk for constipation related serious adverse reactions. .

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  Monitor Closely (1)elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

• encorafenib

  Monitor Closely (1)encorafenib, tetracycline. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.

• enoxaparin

  Minor (1)tetracycline increases effects of enoxaparin by pharmacodynamic synergism. Minor/Significance Unknown.

• entrectinib

  Serious - Use Alternative (2)tetracycline will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of moderate CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce dose to 200 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing moderate CYP3A inhibitor for 3-5 elimination half-lives.
  
  metronidazole will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of moderate CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce dose to 200 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing moderate CYP3A inhibitor for 3-5 elimination half-lives.

• enzalutamide

  Serious - Use Alternative (1)enzalutamide will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• eplerenone

  Minor (1)metronidazole will increase the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ergotamine

  Serious - Use Alternative (1)metronidazole will increase the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erlotinib

  Monitor Closely (1)metronidazole will increase the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• erythromycin base

  Serious - Use Alternative (1)metronidazole will increase the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  Serious - Use Alternative (1)metronidazole will increase the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  Serious - Use Alternative (1)metronidazole will increase the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin stearate

  Serious - Use Alternative (1)metronidazole will increase the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• esmolol

  Monitor Closely (1)bismuth subsalicylate, esmolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• esomeprazole

  Minor (1)esomeprazole increases levels of bismuth subsalicylate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• estradiol

  Monitor Closely (3)metronidazole will decrease the level or effect of estradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will decrease the level or effect of estradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• estradiol vaginal

  Minor (2)tetracycline will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  metronidazole will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• estrogens conjugated synthetic

  Monitor Closely (3)metronidazole will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• estropipate

  Monitor Closely (3)metronidazole will decrease the level or effect of estropipate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will decrease the level or effect of estropipate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• ethanol

  Monitor Closely (1)metronidazole, ethanol. Mechanism: decreasing metabolism. Use Caution/Monitor. Disulfiram like reaction.Minor (1)metronidazole will increase the level or effect of ethanol by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

• ethinylestradiol

  Monitor Closely (2)metronidazole will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  tetracycline will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• ethotoin

  Monitor Closely (1)metronidazole will increase the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• etonogestrel

  Monitor Closely (1)metronidazole will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• etravirine

  Monitor Closely (3)metronidazole will increase the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  etravirine will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• eucalyptus

  Minor (1)metronidazole will increase the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• everolimus

  Serious - Use Alternative (1)metronidazole will increase the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fedratinib

  Monitor Closely (1)fedratinib will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.

• felodipine

  Monitor Closely (1)metronidazole will increase the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fentanyl

  Serious - Use Alternative (2)tetracycline will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
  
  metronidazole will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl intranasal

  Serious - Use Alternative (2)metronidazole will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
  
  tetracycline will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl transdermal

  Serious - Use Alternative (2)tetracycline will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
  
  metronidazole will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl transmucosal

  Serious - Use Alternative (2)tetracycline will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.
  
  metronidazole will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• ferric maltol

  Serious - Use Alternative (1)ferric maltol decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• ferrous fumarate

  Serious - Use Alternative (1)ferrous fumarate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• ferrous gluconate

  Serious - Use Alternative (1)ferrous gluconate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• ferrous sulfate

  Serious - Use Alternative (1)ferrous sulfate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• fesoterodine

  Monitor Closely (1)metronidazole will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fexinidazole

  Serious - Use Alternative (1)fexinidazole will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.

• finasteride

  Minor (1)metronidazole will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• finerenone

  Monitor Closely (2)metronidazole will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.
  
  tetracycline will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.

• flibanserin

  Contraindicated (2)tetracycline will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of flibanserin with moderate or strong CYP3A4 inhibitors is contraindicated. Severe hypotension or syncope can occur.
  
  metronidazole will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of flibanserin with moderate or strong CYP3A4 inhibitors is contraindicated. Severe hypotension or syncope can occur.

• fludrocortisone

  Monitor Closely (1)metronidazole will increase the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fluorouracil

  Monitor Closely (1)metronidazole increases toxicity of fluorouracil by decreasing elimination. Use Caution/Monitor.

• flurbiprofen

  Minor (1)metronidazole will increase the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• fluvastatin

  Minor (1)metronidazole will increase the level or effect of fluvastatin by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• fondaparinux

  Minor (1)tetracycline increases effects of fondaparinux by pharmacodynamic synergism. Minor/Significance Unknown.

• fosamprenavir

  Monitor Closely (1)metronidazole will increase the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fosaprepitant

  Monitor Closely (1)metronidazole will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fosphenytoin

  Monitor Closely (1)metronidazole will increase the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)fosphenytoin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• galantamine

  Minor (1)metronidazole will increase the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• guanfacine

  Monitor Closely (1)metronidazole will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.

• heparin

  Minor (1)tetracycline increases effects of heparin by pharmacodynamic synergism. Minor/Significance Unknown.

• hydrocortisone

  Monitor Closely (1)metronidazole will increase the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydroxyprogesterone caproate (DSC)

  Monitor Closely (1)metronidazole will increase the level or effect of hydroxyprogesterone caproate (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ibrutinib

  Monitor Closely (1)metronidazole increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate CYP3A4 inhibitors, reduce ibrutinib dose to 280 mg qDay (B-cell malignancies) or 420 mg qDay (graft versus host disease). After CYP3A inhibitor discontinuation, resume previous dose of ibrutinib.

• ibuprofen

  Minor (1)metronidazole will increase the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• ibuprofen IV

  Minor (1)metronidazole will increase the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• idelalisib

  Serious - Use Alternative (1)idelalisib will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

• ifosfamide

  Monitor Closely (2)tetracycline decreases effects of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of a CYP3A4 inhibitor may decrease metabolism of ifosfamide, potentially reducing ifosfamide therapeutic effects.
  
  metronidazole decreases effects of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of a CYP3A4 inhibitor may decrease metabolism of ifosfamide, potentially reducing ifosfamide therapeutic effects.

• iloperidone

  Monitor Closely (2)metronidazole will increase the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  iloperidone increases levels of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.

• imatinib

  Minor (1)metronidazole will increase the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• imipramine

  Minor (1)metronidazole will increase the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• indinavir

  Monitor Closely (1)metronidazole will increase the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• infigratinib

  Serious - Use Alternative (2)tetracycline will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  metronidazole will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• irinotecan

  Minor (1)metronidazole will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.Serious - Use Alternative (1)tetracycline will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• irinotecan liposomal

  Minor (1)metronidazole will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.Serious - Use Alternative (1)tetracycline will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• iron dextran complex

  Serious - Use Alternative (1)iron dextran complex decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• iron sucrose

  Serious - Use Alternative (1)iron sucrose decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• isavuconazonium sulfate

  Monitor Closely (2)metronidazole will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isoniazid

  Monitor Closely (1)metronidazole will increase the level or effect of isoniazid by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

• isotretinoin

  Serious - Use Alternative (1)isotretinoin, tetracycline. Mechanism: unknown. Contraindicated. Risk of pseudotumor cerebri.

• isradipine

  Minor (1)metronidazole will increase the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• istradefylline

  Monitor Closely (1)istradefylline will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.

• itraconazole

  Minor (1)metronidazole will increase the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ivabradine

  Serious - Use Alternative (2)tetracycline will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ivabradine with moderate CYP3A4 inhibitors.
  
  metronidazole will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ivabradine with moderate CYP3A4 inhibitors.

• ivacaftor

  Monitor Closely (1)metronidazole increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce ivacaftor dose if coadministered with moderate CYP3A4 inhibitors. See specific ivacaftor-containing product for precise dosage modification.

• ivosidenib

  Monitor Closely (2)tetracycline will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with moderate CYP3A4 inhibitors may increase ivosidenib plasma concentrations, thus increasing the risk of QTc prolongation. Monitor for increased risk of QTc interval prolongation.
  
  metronidazole will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with moderate CYP3A4 inhibitors may increase ivosidenib plasma concentrations, thus increasing the risk of QTc prolongation. Monitor for increased risk of QTc interval prolongation.Serious - Use Alternative (1)ivosidenib will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternative therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

• ixabepilone

  Monitor Closely (1)metronidazole will increase the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ketoconazole

  Minor (1)metronidazole will increase the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• labetalol

  Monitor Closely (1)bismuth subsalicylate, labetalol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• lanthanum carbonate

  Monitor Closely (1)lanthanum carbonate decreases levels of tetracycline by cation binding in GI tract. Use Caution/Monitor. Administer oral tetracycline antibiotics at least 2 hr before or after lanthanum. Interaction applies only to oral tetracyclines.

• lapatinib

  Monitor Closely (1)metronidazole will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• larotrectinib

  Minor (1)larotrectinib will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lefamulin

  Monitor Closely (2)metronidazole will increase the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for adverse effects if lefamulin is coadministered with moderate CYP3A inhibitors.
  
  tetracycline will increase the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for adverse effects if lefamulin is coadministered with moderate CYP3A inhibitors.

• lemborexant

  Serious - Use Alternative (2)tetracycline will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lemborexant with moderate or strong CYP3A inhibitors.
  
  metronidazole will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lemborexant with moderate or strong CYP3A inhibitors.

• lenacapavir

  Monitor Closely (1)lenacapavir will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.

• levamlodipine

  Monitor Closely (2)tetracycline will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate and strong CYP3A inhibitors results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is coadministered with CYP3A inhibitors to determine the need for dose adjustment.
  
  metronidazole will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate and strong CYP3A inhibitors results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is coadministered with CYP3A inhibitors to determine the need for dose adjustment.

• levoketoconazole

  Minor (2)metronidazole will increase the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  levoketoconazole will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  Monitor Closely (2)metronidazole will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.
  
  tetracycline will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.

• lithium

  Minor (1)metronidazole increases levels of lithium by decreasing metabolism. Minor/Significance Unknown.

• lomitapide

  Contraindicated (2)metronidazole increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.
  
  tetracycline increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.

• lonafarnib

  Contraindicated (2)tetracycline will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lonafarnib is a sensitive CYP3A4 substrate. Coadministration with strong or moderate CYP3A4 inhibitors is contraindicated.
  
  metronidazole will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lonafarnib is a sensitive CYP3A4 substrate. Coadministration with strong or moderate CYP3A4 inhibitors is contraindicated.

• lopinavir

  Monitor Closely (1)metronidazole will increase the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• loratadine

  Monitor Closely (1)metronidazole will increase the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lorlatinib

  Monitor Closely (1)lorlatinib will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• losartan

  Monitor Closely (1)metronidazole will increase the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.

• lovastatin

  Serious - Use Alternative (1)metronidazole will increase the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lumateperone

  Monitor Closely (2)tetracycline will increase the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce lumateperone dose to 21 mg/day if coadministered with moderate CYP3A4 inhibitors.
  
  metronidazole will increase the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce lumateperone dose to 21 mg/day if coadministered with moderate CYP3A4 inhibitors.

• lumefantrine

  Monitor Closely (1)metronidazole will increase the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lurbinectedin

  Serious - Use Alternative (2)tetracycline will increase the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  metronidazole will increase the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• magnesium chloride

  Serious - Use Alternative (1)magnesium chloride decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• magnesium citrate

  Serious - Use Alternative (1)magnesium citrate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• magnesium hydroxide

  Serious - Use Alternative (1)magnesium hydroxide decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• magnesium oxide

  Serious - Use Alternative (1)magnesium oxide decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• magnesium sulfate

  Serious - Use Alternative (1)magnesium sulfate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• magnesium supplement

  Monitor Closely (1)magnesium supplement will decrease the level or effect of tetracycline by Other (see comment). Modify Therapy/Monitor Closely. Formation of an insoluble complex reduces absorption of the drug through intestinal tract; administer magnesium 2hr before the tetracycline or 4hr after the tetracycline

• maraviroc

  Monitor Closely (1)metronidazole will increase the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mavacamten

  Monitor Closely (2)metronidazole will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.
  
  tetracycline will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• mebendazole

  Serious - Use Alternative (1)mebendazole increases toxicity of metronidazole by Other (see comment). Avoid or Use Alternate Drug. Comment: May increase the risk for toxic epidermal necrolysis or Stevens-Johnson syndrome.

• mefloquine

  Monitor Closely (2)tetracycline will increase the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• meloxicam

  Minor (1)metronidazole will increase the level or effect of meloxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• mestranol

  Monitor Closely (3)metronidazole will decrease the level or effect of mestranol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will decrease the level or effect of mestranol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• methadone

  Monitor Closely (1)metronidazole will increase the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• methotrexate

  Monitor Closely (1)tetracycline increases levels of methotrexate by decreasing elimination. Use Caution/Monitor. If tetracyclines cannot be avoided in patients receiving high-dose methotrexate, closely monitor methotrexate plasma concentrations and patients for signs and symptoms of toxicity.

• methoxsalen

  Monitor Closely (1)methoxsalen, tetracycline. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive photosensitizing effects.

• methoxyflurane

  Serious - Use Alternative (1)tetracycline, methoxyflurane. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of nephrotoxicity.

• methyl aminolevulinate

  Serious - Use Alternative (1)tetracycline, methyl aminolevulinate. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Each drug may increase the photosensitizing effect of the other.

• methylprednisolone

  Monitor Closely (1)metronidazole will increase the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• metoclopramide intranasal

  Monitor Closely (1)bismuth subsalicylate will decrease the level or effect of metoclopramide intranasal by Other (see comment). Use Caution/Monitor. Coadministration of metoclopramide intranasal with drugs that impair GI motility may decrease systemic absorption of metoclopramide. Monitor for reduced therapeutic effect.

• metoprolol

  Monitor Closely (1)bismuth subsalicylate, metoprolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• microbiota oral

  Serious - Use Alternative (1)tetracycline decreases effects of microbiota oral by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Microbiota oral contains bacterial spores. Antibacterial agents may decrease efficacy if coadministered. Complete antibiotic regimens 2-4 days before initiating microbiota oral. .

• midazolam

  Monitor Closely (1)metronidazole will increase the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• midazolam intranasal

  Serious - Use Alternative (2)metronidazole will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of moderate CYP3A4 inhibitors with midazolam intranasal causes higher midazolam systemic exposure, which may prolong sedation.
  
  tetracycline will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of moderate CYP3A4 inhibitors with midazolam intranasal causes higher midazolam systemic exposure, which may prolong sedation.

• minocycline

  Serious - Use Alternative (1)bismuth subsalicylate decreases levels of minocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• mipomersen

  Monitor Closely (1)mipomersen, tetracycline. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

• mitotane

  Monitor Closely (1)mitotane decreases levels of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.

• mobocertinib

  Serious - Use Alternative (2)tetracycline will increase the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use of moderate CYP3A4 inhibitor unavoidable, reduce mobocertinib dose by ~50% (eg, 160 to 80 mg); closely monitor QTc interval.
  
  metronidazole will increase the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use of moderate CYP3A4 inhibitor unavoidable, reduce mobocertinib dose by ~50% (eg, 160 to 80 mg); closely monitor QTc interval.

• montelukast

  Minor (1)metronidazole will increase the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nadolol

  Monitor Closely (1)bismuth subsalicylate, nadolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• nafcillin

  Monitor Closely (1)nafcillin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)tetracycline decreases effects of nafcillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• naldemedine

  Monitor Closely (2)tetracycline increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.
  
  metronidazole increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.

• naloxegol

  Serious - Use Alternative (2)tetracycline will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministation of naloxegol with moderate CYP3A4 inhibitors is unavoidable, reduce naloxegol dose to 12.5 mg qDay
  
  metronidazole will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministation of naloxegol with moderate CYP3A4 inhibitors is unavoidable, reduce naloxegol dose to 12.5 mg qDay

• nateglinide

  Monitor Closely (1)metronidazole will increase the level or effect of nateglinide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• nebivolol

  Monitor Closely (1)bismuth subsalicylate, nebivolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• nelfinavir

  Monitor Closely (1)metronidazole will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• neratinib

  Serious - Use Alternative (2)tetracycline will increase the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inhibitors.
  
  metronidazole will increase the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inhibitors.

• niacin

  Minor (1)tetracycline will decrease the level or effect of niacin by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• nicardipine

  Monitor Closely (1)metronidazole will increase the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nifedipine

  Minor (1)metronidazole will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nilotinib

  Monitor Closely (1)metronidazole will increase the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nimodipine

  Minor (1)metronidazole will increase the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nisoldipine

  Monitor Closely (1)metronidazole will increase the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nitrendipine

  Minor (1)metronidazole will increase the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nitroglycerin IV

  Minor (1)nitroglycerin IV, metronidazole. Mechanism: decreasing metabolism. Minor/Significance Unknown. Disulfiram like reaction.

• olaparib

  Serious - Use Alternative (2)tetracycline will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with moderate CYP3A inhibitors cannot be avoided, reduce olaparib dose to 200 mg (capsule) or 150 mg (tablet) PO BID. Do not substitute tablets with capsules.
  
  metronidazole will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with moderate CYP3A inhibitors cannot be avoided, reduce olaparib dose to 200 mg (capsule) or 150 mg (tablet) PO BID. Do not substitute tablets with capsules.

• oliceridine

  Monitor Closely (2)metronidazole will increase the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.
  
  tetracycline will increase the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.

• omadacycline

  Monitor Closely (1)bismuth subsalicylate will decrease the level or effect of omadacycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.

• omaveloxolone

  Serious - Use Alternative (2)tetracycline will increase the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unavoidable, reduce omaveloxolone dose to 100 mg/day. Closely monitor for adverse effects. If adverse effects emerge, further reduce to 50 mg/day.
  
  metronidazole will increase the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unavoidable, reduce omaveloxolone dose to 100 mg/day. Closely monitor for adverse effects. If adverse effects emerge, further reduce to 50 mg/day.

• omeprazole

  Minor (1)omeprazole increases levels of bismuth subsalicylate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• onabotulinumtoxinA

  Serious - Use Alternative (1)tetracycline increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• oxacillin

  Serious - Use Alternative (1)tetracycline decreases effects of oxacillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. bacteriostatic agents may inhibit the effects of bactericidal agents.

• oxybutynin

  Minor (1)metronidazole will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• oxytetracycline

  Serious - Use Alternative (1)bismuth subsalicylate decreases levels of oxytetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• paclitaxel

  Minor (1)metronidazole will increase the level or effect of paclitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• paclitaxel protein bound

  Minor (1)metronidazole will increase the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pacritinib

  Serious - Use Alternative (2)tetracycline will increase the level or effect of pacritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  metronidazole will increase the level or effect of pacritinib by affecting hepatic enzyme CYP2E1 metabolism. Avoid or Use Alternate Drug.

• palbociclib

  Monitor Closely (2)metronidazole will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• pancuronium

  Serious - Use Alternative (1)tetracycline increases effects of pancuronium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• pantothenic acid

  Minor (2)metronidazole will decrease the level or effect of pantothenic acid by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  tetracycline will decrease the level or effect of pantothenic acid by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• parecoxib

  Monitor Closely (1)metronidazole will increase the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.Minor (1)metronidazole will increase the level or effect of parecoxib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pazopanib

  Monitor Closely (1)metronidazole will increase the level or effect of pazopanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of pazopanib with strong CYP3A4 inhibitors if possible; if must coadminister, decrease pazopanib dose to 400 mg/day

• pemigatinib

  Serious - Use Alternative (2)metronidazole will increase the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pemigatinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pemigatinib dose.
  
  tetracycline will increase the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pemigatinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pemigatinib dose.

• penbutolol

  Monitor Closely (1)bismuth subsalicylate, penbutolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• penicillin G aqueous

  Serious - Use Alternative (1)tetracycline decreases effects of penicillin G aqueous by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• penicillin VK

  Serious - Use Alternative (1)tetracycline decreases effects of penicillin VK by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• pexidartinib

  Serious - Use Alternative (2)metronidazole will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.
  
  tetracycline will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.

• phenindione

  Minor (1)tetracycline increases effects of phenindione by pharmacodynamic synergism. Minor/Significance Unknown.

• phenobarbital

  Serious - Use Alternative (1)phenobarbital will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• phenytoin

  Monitor Closely (1)metronidazole will increase the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)phenytoin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• pimozide

  Serious - Use Alternative (1)metronidazole increases levels of pimozide by decreasing metabolism. Contraindicated. Risk of QT interval prolongation.Minor (1)metronidazole will increase the level or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pindolol

  Monitor Closely (1)bismuth subsalicylate, pindolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• pioglitazone

  Minor (1)metronidazole will increase the level or effect of pioglitazone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• piperacillin

  Monitor Closely (1)tetracycline decreases effects of piperacillin by pharmacodynamic antagonism. Use Caution/Monitor. bacteriostatic agents may inhibit the effects of bactericidal agents.

• piroxicam

  Minor (1)metronidazole will increase the level or effect of piroxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• pivmecillinam

  Serious - Use Alternative (1)tetracycline decreases effects of pivmecillinam by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• polycarbophil

  Monitor Closely (1)polycarbophil decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

• polysaccharide iron

  Serious - Use Alternative (1)polysaccharide iron decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• porfimer

  Monitor Closely (1)tetracycline, porfimer. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Enhanced photosensitivity.

• prednisone

  Monitor Closely (1)metronidazole will increase the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• primidone

  Serious - Use Alternative (1)primidone will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• propafenone

  Minor (1)metronidazole will increase the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• propranolol

  Monitor Closely (1)bismuth subsalicylate, propranolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• propylene glycol

  Serious - Use Alternative (1)metronidazole, propylene glycol. Mechanism: decreasing metabolism. Contraindicated. Disulfiram like reaction.

• protamine

  Minor (1)tetracycline increases effects of protamine by pharmacodynamic synergism. Minor/Significance Unknown.

• pyridoxine

  Minor (2)tetracycline will decrease the level or effect of pyridoxine by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  metronidazole will decrease the level or effect of pyridoxine by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• pyridoxine (Antidote)

  Minor (2)tetracycline will decrease the level or effect of pyridoxine (Antidote) by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  metronidazole will decrease the level or effect of pyridoxine (Antidote) by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• quetiapine

  Monitor Closely (1)metronidazole will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• quinidine

  Monitor Closely (1)metronidazole will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• quinine

  Minor (1)metronidazole will increase the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ramelteon

  Minor (2)metronidazole will increase the level or effect of ramelteon by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
  
  metronidazole will increase the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ranolazine

  Serious - Use Alternative (1)metronidazole will increase the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rapacuronium

  Serious - Use Alternative (1)tetracycline increases effects of rapacuronium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• repaglinide

  Monitor Closely (1)metronidazole will increase the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rifabutin

  Monitor Closely (1)rifabutin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rifampin

  Monitor Closely (1)rifampin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rifapentine

  Monitor Closely (1)rifapentine will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rimegepant

  Monitor Closely (2)tetracycline will increase the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid repeating rimegepant dose within 48 hr if coadministered with a moderate CYP3A4 inhibitor.
  
  metronidazole will increase the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid repeating rimegepant dose within 48 hr if coadministered with a moderate CYP3A4 inhibitor.

• ritonavir

  Monitor Closely (1)metronidazole will increase the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rocuronium

  Serious - Use Alternative (1)tetracycline increases effects of rocuronium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• rose hips

  Serious - Use Alternative (1)rose hips decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.Minor (1)tetracycline decreases levels of rose hips by increasing elimination. Minor/Significance Unknown.

• rucaparib

  Monitor Closely (1)rucaparib will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.

• ruxolitinib

  Monitor Closely (2)tetracycline will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ruxolitinib topical

  Monitor Closely (2)tetracycline will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• saquinavir

  Monitor Closely (1)metronidazole will increase the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sarecycline

  Monitor Closely (1)bismuth subsalicylate will decrease the level or effect of sarecycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.

• saxagliptin

  Minor (1)metronidazole will increase the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• selinexor

  Serious - Use Alternative (1)selinexor, metronidazole. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.

• selumetinib

  Serious - Use Alternative (2)tetracycline will increase the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors cannot be avoided, reduce selumetinib dosage (refer to selumetinib monograph for further information). After discontinuation of the strong or moderate CYP3A4 inhibitor for 3 elimination half-lives, resume selumetinib dose that was taken before initiating the inhibitor.
  
  metronidazole will increase the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors cannot be avoided, reduce selumetinib dosage (refer to selumetinib monograph for further information). After discontinuation of the strong or moderate CYP3A4 inhibitor for 3 elimination half-lives, resume selumetinib dose that was taken before initiating the inhibitor.

• silodosin

  Serious - Use Alternative (1)metronidazole will increase the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• simvastatin

  Serious - Use Alternative (1)metronidazole will increase the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• siponimod

  Serious - Use Alternative (2)metronidazole will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a moderate or strong CYP3A4 inhibitor PLUS a moderate or strong CYP2C9 inhibitor is not recommended.
  
  tetracycline will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a moderate or strong CYP3A4 inhibitor PLUS a moderate or strong CYP2C9 inhibitor is not recommended.

• sirolimus

  Serious - Use Alternative (1)metronidazole will increase the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sodium bicarbonate

  Serious - Use Alternative (1)sodium bicarbonate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• sodium citrate/citric acid

  Serious - Use Alternative (1)sodium citrate/citric acid decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• sodium picosulfate/magnesium oxide/anhydrous citric acid

  Monitor Closely (3)tetracycline decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.
  
  metronidazole decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.
  
  sodium picosulfate/magnesium oxide/anhydrous citric acid decreases levels of tetracycline by cation binding in GI tract. Use Caution/Monitor. Take at least 2 hours before and not less than 6 hours after administration of sodium picosulfate, magnesium oxide and anhydrous citric acid to avoid magnesium chelation.

• sodium sulfate/?magnesium sulfate/potassium chloride

  Serious - Use Alternative (1)sodium sulfate/?magnesium sulfate/potassium chloride decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Administer tetracyclines at least 2 hr before and no less than 6 hr after each dose to avoid chelation with magnesium. .

• sodium sulfate/potassium sulfate/magnesium sulfate

  Serious - Use Alternative (1)sodium sulfate/potassium sulfate/magnesium sulfate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Administer tetracyclines at least 2 hr before and no less than 6 hr after each dose to avoid chelation with magnesium. .

• solifenacin

  Monitor Closely (1)metronidazole will increase the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sonidegib

  Monitor Closely (2)tetracycline will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of sonidegib with moderate CYP3A4 inhibitors. If a moderate CYP3A inhibitor must be used, administer the moderate CYP3A inhibitor for <14 days and monitor closely for adverse reactions, particularly musculoskeletal adverse reactions.
  
  metronidazole will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of sonidegib with moderate CYP3A4 inhibitors. If a moderate CYP3A inhibitor must be used, administer the moderate CYP3A inhibitor for <14 days and monitor closely for adverse reactions, particularly musculoskeletal adverse reactions.

• sotalol

  Monitor Closely (1)bismuth subsalicylate, sotalol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• sparsentan

  Monitor Closely (2)tetracycline will increase the level or effect of sparsentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No dosage adjustment needed. Monitor blood pressure, serum potassium, edema, and kidney function regularly if sparsentan is coadministered with moderate CYP3A4 inhibitors.
  
  metronidazole will increase the level or effect of sparsentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No dosage adjustment needed. Monitor blood pressure, serum potassium, edema, and kidney function regularly if sparsentan is coadministered with moderate CYP3A4 inhibitors.

• stiripentol

  Monitor Closely (1)stiripentol, tetracycline. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.

• strontium ranelate

  Serious - Use Alternative (1)strontium ranelate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Contraindicated. Suspend strontium ranelate during antibiotic therapy.

• succinylcholine

  Serious - Use Alternative (1)tetracycline increases effects of succinylcholine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• sucralfate

  Minor (1)sucralfate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• sufentanil

  Minor (1)metronidazole will increase the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• sufentanil SL

  Monitor Closely (2)tetracycline will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.
  
  metronidazole will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.

• sulfamethoxazole

  Monitor Closely (1)metronidazole, sulfamethoxazole. Mechanism: decreasing metabolism. Use Caution/Monitor. Disulfiram like reaction.Minor (1)metronidazole will increase the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• sunitinib

  Monitor Closely (1)metronidazole will increase the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• suvorexant

  Monitor Closely (2)tetracycline will increase the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease suvorexant starting dose to 5 mg HS if coadministered with moderate CYP3A4 inhibitors
  
  metronidazole will increase the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease suvorexant starting dose to 5 mg HS if coadministered with moderate CYP3A4 inhibitors

• tacrolimus

  Monitor Closely (1)metronidazole will increase the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tadalafil

  Monitor Closely (2)tetracycline will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce tadalafil clearance increasing systemic exposure to tadalafil; increased levels may result in increased associated adverse events.
  
  metronidazole will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tamoxifen

  Monitor Closely (1)metronidazole, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).

• tamsulosin

  Monitor Closely (1)metronidazole increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.

• tazemetostat

  Monitor Closely (1)tazemetostat will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)metronidazole will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of tazemetostat with moderate CYP3A4 inhibitors. If coadministration is unavoidable, reduce tazemetostat current dose (see drug monograph Dosage Modifications).
  
  tetracycline will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of tazemetostat with moderate CYP3A4 inhibitors. If coadministration is unavoidable, reduce tazemetostat current dose (see drug monograph Dosage Modifications).

• tecovirimat

  Monitor Closely (1)tecovirimat will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

• temocillin

  Serious - Use Alternative (1)tetracycline decreases effects of temocillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• temsirolimus

  Monitor Closely (1)metronidazole will increase the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tetracycline

  Serious - Use Alternative (1)bismuth subsalicylate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• tezacaftor

  Monitor Closely (2)metronidazole will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tezacaftor dosage regimen if coadministered with a moderate CYP3A inhibitor.
  
  tetracycline will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tezacaftor dosage regimen if coadministered with a moderate CYP3A inhibitor.

• theophylline

  Monitor Closely (1)metronidazole will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• thiamine

  Minor (2)tetracycline will decrease the level or effect of thiamine by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  metronidazole will decrease the level or effect of thiamine by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.

• ticarcillin

  Serious - Use Alternative (1)tetracycline decreases effects of ticarcillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• timolol

  Monitor Closely (1)bismuth subsalicylate, timolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• tinidazole

  Monitor Closely (2)tetracycline will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  metronidazole will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tipranavir

  Monitor Closely (1)metronidazole will increase the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tobramycin inhaled

  Monitor Closely (1)tobramycin inhaled and bismuth subsalicylate both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicity

• tofacitinib

  Monitor Closely (2)tetracycline increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No specific dose adjustment recommended when tofacitinib coadministered with moderate CYP3A4 inhibitors; decrease tofacitinib dose if coadministered with both moderate CYP3A4 and potent CYP2C19 inhibitors .
  
  metronidazole increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No specific dose adjustment recommended when tofacitinib coadministered with moderate CYP3A4 inhibitors; decrease tofacitinib dose if coadministered with both moderate CYP3A4 and potent CYP2C19 inhibitors.

• tolbutamide

  Minor (1)metronidazole will increase the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• tolterodine

  Monitor Closely (1)metronidazole will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tolvaptan

  Serious - Use Alternative (1)metronidazole will increase the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• trabectedin

  Monitor Closely (2)metronidazole will increase the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tetracycline will increase the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• trazodone

  Monitor Closely (1)metronidazole will increase the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tretinoin

  Contraindicated (1)tetracycline, tretinoin. Either increases toxicity of the other by unspecified interaction mechanism. Contraindicated. Both tretinoin and tetracyclines can cause increased intracranial pressure.Serious - Use Alternative (1)tetracycline, tretinoin. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

• tretinoin topical

  Serious - Use Alternative (1)tetracycline, tretinoin topical. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

• triamcinolone acetonide injectable suspension

  Monitor Closely (1)metronidazole will increase the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• triazolam

  Monitor Closely (1)metronidazole will increase the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• trimagnesium citrate anhydrous

  Monitor Closely (1)trimagnesium citrate anhydrous decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Multivalent cation-containing products may reduce bioavailability of tetracyclines; administer tetracycline at least 2 hr before or 6 hr after magnesium; use alternatives if available.

• tripotassium dicitratobismuthate

  Serious - Use Alternative (1)tripotassium dicitratobismuthate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• tucatinib

  Serious - Use Alternative (1)tucatinib will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.

• typhoid vaccine live

  Serious - Use Alternative (2)tetracycline decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.
  
  metronidazole decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.

• vardenafil

  Monitor Closely (2)tetracycline will increase the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Vardenafil dose may need to be reduced if coadministered with moderate or strong CYP3A4 inhibitors
  
  metronidazole will increase the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Vardenafil dose may need to be reduced if coadministered with moderate or strong CYP3A4 inhibitors

• vecuronium

  Serious - Use Alternative (1)tetracycline increases effects of vecuronium by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of respiratory depression.

• venetoclax

  Serious - Use Alternative (2)tetracycline will increase the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If a moderate CYP3A inhibitor must be used, reduce the venetoclax dose by at least 50%. Monitor more closely for signs of venetoclax toxicities.
  
  metronidazole will increase the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If a moderate CYP3A inhibitor must be used, reduce the venetoclax dose by at least 50%. Monitor more closely for signs of venetoclax toxicities.

• verapamil

  Monitor Closely (1)metronidazole will increase the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• verteporfin

  Minor (1)tetracycline, verteporfin. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased phototoxicity.

• vinblastine

  Minor (1)metronidazole will increase the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vincristine

  Minor (1)metronidazole will increase the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vincristine liposomal

  Minor (1)metronidazole will increase the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vinorelbine

  Minor (1)metronidazole will increase the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• voclosporin

  Monitor Closely (2)tetracycline will increase the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce voclosporin daily dosage to 15.8 mg PO in AM and 7.9 mg PO in PM.
  
  metronidazole will increase the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce voclosporin daily dosage to 15.8 mg PO in AM and 7.9 mg PO in PM.

• voriconazole

  Minor (1)metronidazole will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• voxelotor

  Serious - Use Alternative (1)voxelotor will increase the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.

• warfarin

  Monitor Closely (1)tetracycline increases effects of warfarin by unspecified interaction mechanism. Use Caution/Monitor.Serious - Use Alternative (1)bismuth subsalicylate increases effects of warfarin by anticoagulation. Avoid or Use Alternate Drug.

• zaleplon

  Minor (1)metronidazole will increase the level or effect of zaleplon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zanubrutinib

  Monitor Closely (2)metronidazole will increase the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce zanubrutinib (a CYP3A4 substrate) to 80 mg PO BID to when coadministered with a moderate CYP3A4 inhibitor. Interrupt dose as recommended for adverse reactions. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib.
  
  tetracycline will increase the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce zanubrutinib (a CYP3A4 substrate) to 80 mg PO BID to when coadministered with a moderate CYP3A4 inhibitor. Interrupt dose as recommended for adverse reactions. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib.

• zinc

  Monitor Closely (1)zinc will decrease the level or effect of tetracycline by cation binding in GI tract. Modify Therapy/Monitor Closely. Separate administration of oral tetracycline derivatives and oral zinc salts by at least 2 hr.

• ziprasidone

  Minor (1)metronidazole will increase the level or effect of ziprasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zolpidem

  Minor (1)metronidazole will increase the level or effect of zolpidem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zonisamide

  Minor (1)metronidazole will increase the level or effect of zonisamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.