Dosing & Uses
Dosage Forms & Strengths
tablets
- 50mg
- 100mg
- 300mg
oral syrup
- 50mg/5mL
injectable solution
- 100mg/mL
Latent Tuberculosis Infection
Treatment of latent TB infection greatly reduces the risk that TB infection will progress to acitve disease
>30 kg: 300 mg PO qDay x9 months
3-month regimen
- Recommended for patients aged 12 years and older who are at high risk for developing TB disease including anyone who has had recent exposure to contagious TB, conversion from negative to positive on a test for TB infection, or a chest X-ray indicating prior TB disease
- Persons with HIV who are otherwise healthy and not taking antiretrovirals may also use this regimen
- 900 mg PO once weekly x3 months (administer with rifapentine 900 mg once weekly)
- Administered as DOT
- Not recommended for children <2 years, pregnant women or women planning to become pregnant, HIV-infected persons taking antiretrovirals, and patients whose TB infection is presumed to be the result of exposure to a person with TB disease that is resistant to 1 of the 2 drugs
- References: CDC MMWR 2011;60:1650-3 and NEJM 2011;365:2155-2166
Active Tuberculosis Disease
5 mg/kg PO/IM qDay, not to exceed 300 mg qDay
15 mg/kg PO/IM up; not to exceed 900 mg 1-3 times/week
Used in multi-drug regimen containing rifampin (or ribabutin or rifapentin), pyrazinamide, and ethambutol
Duration of treatment dependent on regimen consisting of an initial phase of treatment and a continutation phase of treatment
Note: Daily treatment has best results for HIV positive individuals
See Also Combos
With rifampin (Rifamate)
With rifampin and pyrizinamide (Rifater)
Other Indications & Uses
Newly infected patients
Household members and close associates of people recently diagnosed wtih TB
+ve TB skin test with +ve non-progressive chest x-ray
+ve TB skin test with underlying disease or immunosuppression
+ve TB skin test, <35 years old; >35 years old weigh use against risk of hepatitis
Dosage Forms & Strengths
tablets
- 50mg
- 100mg
- 300mg
oral syrup
- 50mg/5mL
injectable solution
- 100mg/mL
Latent Tuberculosis Infection
Treatment of latent TB infection greatly reduces the risk that TB infection will progress to acitve disease
10-15 mg/kg PO qDay; not to exceed 300 mg/day
3-month regimen
- Recommended for patients aged 12 years and older who are at high risk for developing TB disease including anyone who has had recent exposure to contagious TB, conversion from negative to positive on a test for TB infection, or a chest X-ray indicating prior TB disease
- Use for children aged 2-11 years and patients with underlying conditions associated with TB should be considered on a case-by-case basis; preferred regimen for this age group is daily isoniazid for 9 months
- Not recommended for children <2 years
- >12 years: isoniazid 900 mg PO plus rifapentine 900 mg PO once weekly for 3 months
- References: CDC MMWR 2011;60:1650-3 and NEJM 2011;365:2155-2166
Active Tuberculosis Disease
10-15 mg/kg PO qDay; not to exceed 300 mg/day OR
20-30 mg/kg (up to 900 mg) 2 times/week
Used in multi-drug regimen
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Contraindicated (20)
- cobimetinib
isoniazid will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration with strong CYP3A4 inhibitors with (increases cobimetinib systemic exposure by 6.7-fold).
- conivaptan
isoniazid will increase the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of conivaptan with strong CYP3A4 inhibitors is contraindicated.
- dihydroergotamine
isoniazid will increase the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- dihydroergotamine intranasal
isoniazid will increase the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- eliglustat
isoniazid will increase the level or effect of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors are contraindicated with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors
isoniazid increases levels of eliglustat by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. If coadministered with strong or moderate CYP2D6 inhibitors, reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive and intermediate metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors. - flibanserin
isoniazid 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.
- infigratinib
isoniazid will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- ivabradine
isoniazid will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of ivabradine with strong CYP3A4 inhibitors is contraindicated.
- ketoconazole
isoniazid decreases levels of ketoconazole by unspecified interaction mechanism. Contraindicated.
- levoketoconazole
isoniazid decreases levels of levoketoconazole by unspecified interaction mechanism. Contraindicated.
- lomitapide
isoniazid increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.
- lonafarnib
isoniazid 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.
- lovastatin
isoniazid will increase the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase systemic statin exposure and risk of myopathy, including rhabdomyolysis
- lurasidone
isoniazid will increase the level or effect of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lurasidone and strong CYP3A4 inhibitors is contraindicated.
- mavacamten
isoniazid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.
- naloxegol
isoniazid will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of naloxegol with strong CYP3A4 inhibitors can significantly increase naloxegol systemic exposure which may precipitate opioid withdrawal symptoms
- pacritinib
isoniazid will increase the level or effect of pacritinib by affecting hepatic enzyme CYP2E1 metabolism. Contraindicated.
- regorafenib
isoniazid, regorafenib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase regorafenib levels and decrease exposure of the active metabolites M-2 and M-5.
- venetoclax
isoniazid will increase the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Use of strong CYP3A4 inhibitors is contraindicated with venetoclax during the initial ramp-up dosing phase. If a strong CYP3A inhibitor must be used after the ramp-up phase, reduce the venetoclax dose by at least 75%.
- voclosporin
isoniazid will increase the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
Serious - Use Alternative (100)
- acalabrutinib
isoniazid will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of acalabrutinib with strong CYP3A inhibitors. If a strong CYP3A inhibitor must be used short-term (eg, up to 7 days), temporarily interrupt treatment with acalabrutinib.
- ado-trastuzumab emtansine
isoniazid increases levels of ado-trastuzumab emtansine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. DM1, the cytotoxic component, is metabolized mainly by CYP3A4; strong CYP3A4 inhibitors may increase DM1 exposure and toxicity.
- alfentanil
isoniazid will increase the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Monitor for excessive CNS and respiratory depression
- alfuzosin
isoniazid will increase the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- avanafil
isoniazid will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; significantly increased levels may result in significant adverse events including severe hypotension, syncope, visual changes, and priapism. Coadministration with strong CYP3A4 is contraindicated.
- avapritinib
isoniazid 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
isoniazid increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, reduce axitinib dose by 50%.
- bedaquiline
isoniazid will increase the level or effect of bedaquiline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of bedaquiline with strong CYP3A4 inhibitors for >14 consecutive days, unless the benefit of treatment outweighs the risk
- bosutinib
isoniazid increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors increases bosutinib plasma concentration ~5-fold.
- brigatinib
isoniazid will increase the level or effect of brigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use of a strong CYP3A inhibitor cannot be avoided, reduce the brigatinib once daily dose by about 50% (ie, from 180 mg to 90 mg, or from 90 mg to 60 mg). After discontinuation of a strong CYP3A inhibitor, resume the brigatinib dose that was tolerated prior to initiating the strong CYP3A inhibitor.
- cabazitaxel
isoniazid will increase the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of cabazitaxel with strong CYP3A4 inhibitors should be avoided.
- cabozantinib
isoniazid will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of cabozantinib with strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor is required, decrease cabozantinib dose by 40 mg/day (Cometriq) or by 20 mg/day (Cabometyx). Resume previous dose 2-3 days after strong CYP3A4 inhibitor discontinued.
- ceritinib
isoniazid increases levels of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid if possible; if concomitant use is unavoidable, reduce ceritinib dose by ~33%; after discontinuation of strong CYP3A inhibitor, resume at previous dose.
- cilostazol
isoniazid increases toxicity of cilostazol by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Decrease cilostazol dose by 50%; serum levels of 3,4-dehydrocilostazol (active metabolite) increased by strong CYP2C19 inhibitors.
- clopidogrel
isoniazid decreases effects of clopidogrel by decreasing metabolism. Avoid or Use Alternate Drug. Cytochrome P450 2C19 inhibitors decrease the conversion of clopidogrel to its active form.
- copanlisib
isoniazid will increase the level or effect of copanlisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use with strong CYP3A inhibitors cannot be avoided, reduce copanlisib dose to 45 mg.
- dabrafenib
isoniazid increases levels of dabrafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- desvenlafaxine
isoniazid and desvenlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.
- dronedarone
isoniazid will increase the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- elacestrant
isoniazid will increase the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- encorafenib
isoniazid will increase the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use of a strong CYP3A4 inhibitor is unavoidable, reduce encorafenib dose to one-third of the dose (eg, reduce from 450 mg/day to 150 mg/day). After discontinuing the inhibitor for 3-5 elimination half-lives, resume previous encorafenib dose.
- entrectinib
isoniazid 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.
- eplerenone
isoniazid will increase the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- erdafitinib
isoniazid will increase the level or effect of erdafitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, monitor closely for adverse reactions and consider decreasing dose accordingly. If strong CYP3A4 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.
- ergotamine
isoniazid will increase the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- erythromycin base
isoniazid will increase the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- erythromycin ethylsuccinate
isoniazid will increase the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- erythromycin lactobionate
isoniazid will increase the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- erythromycin stearate
isoniazid will increase the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- esomeprazole
isoniazid will increase the level or effect of esomeprazole by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.
- etravirine
isoniazid will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.
- everolimus
isoniazid will increase the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- fedratinib
isoniazid will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.
isoniazid will increase the level or effect of fedratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. - fentanyl
isoniazid 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
isoniazid 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
isoniazid 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
isoniazid 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.
- fexinidazole
isoniazid will decrease the level or effect of fexinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration, monitor fexinidazole for decreased efficacy owing to decreased plasma concentrations of active M1 and M2 metabolites.
- fluticasone intranasal
isoniazid will increase the level or effect of fluticasone intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors may increase systemic corticosteroid adverse effects; monitor for signs/symptoms of high corticosteroid concentrations including Cushing type signs/symptoms.
- gilteritinib
isoniazid will increase the level or effect of gilteritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternatives to any strong CYP3A4 inhibitor when coadministered with gilteritinib. If such a combination cannot be avoided, closely monitor for gilteritinib-related adverse effects. Interrupt and reduce gilteritinib dosage in patients with serious or life-threatening toxicity.
- glasdegib
isoniazid will increase the level or effect of glasdegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternate therapies that are not strong CYP3A inhibitors or monitor for increased risk of adverse effects, including QTc interval prolongation.
- ibrutinib
isoniazid increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for =7 days), interrupt ibrutinib therapy until strong CYP3A4 inhibitor is discontinued.
- idelalisib
isoniazid will increase the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministered with strong CYP3A inhibitors, monitor for signs of idelalisib toxicity; follow recommendations for dosage modifications if adverse reactions occur
- irinotecan
isoniazid will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- irinotecan liposomal
isoniazid will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- isocarboxazid
isocarboxazid and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug.
- lefamulin
isoniazid will increase the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lefamulin with strong CYP3A inhibitors.
- lemborexant
isoniazid 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.
- linezolid
linezolid and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug. Linezolid may increase serotonin as a result of MAO-A inhibition. If linezolid must be administered, discontinue serotonergic drug immediately and monitor for CNS toxicity. Serotonergic therapy may be resumed 24 hours after last linezolid dose or after 2 weeks of monitoring, whichever comes first.
- lorcaserin
isoniazid and lorcaserin both increase serotonin levels. Avoid or Use Alternate Drug.
- lorlatinib
isoniazid will increase the level or effect of lorlatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering lorlatinib with strong CYP3A inhibitors. If unavoidable, reduce lorlatinib dose by 25 mg/day. If strong CYP3A inhibitor discontinued, increase to previous lorlatinib (dose after 3 plasma half-lives of strong CYP3A inhibitor). See monograph for further details.
- lurbinectedin
isoniazid will increase the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- macitentan
isoniazid will increase the level or effect of macitentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering macitentan with strong CYP3A4 inhibitors
- methylene blue
methylene blue and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug. Methylene blue and isoniazid may increase serotonin as a result of MAO-A inhibition. If methylene blue must be administered, discontinue isoniazid immediately and monitor for CNS toxicity. Isoniazid may be resumed 24 hours after last methylene blue dose or after 2 weeks of monitoring, whichever comes first.
- midazolam intranasal
isoniazid 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.
- midostaurin
isoniazid will increase the level or effect of midostaurin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong CYP3A4 inhibitors cannot be avoided, monitor midostaurin for increased risk of adverse reactions, especially during the first week of treatment.
- mirtazapine
isoniazid will increase the level or effect of mirtazapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- mobocertinib
isoniazid 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.
- neratinib
isoniazid 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.
- nilotinib
isoniazid will increase the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- nisoldipine
isoniazid will increase the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- olaparib
isoniazid will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong CYP3A inhibitors cannot be avoided, reduce olaparib dose to 150 mg (capsule) or 100 mg (tablet) PO BID. Do not substitute tablets with capsules.
- omaveloxolone
isoniazid 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
isoniazid will increase the level or effect of omeprazole by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.
- osimertinib
isoniazid will increase the level or effect of osimertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of osimertinib with strong CYP3A4 inhibitors. If no other alternative treatment exists, monitor patient more closely for adverse effects.
- oxycodone
isoniazid increases levels of oxycodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Oxycodone dose reduction may be warranted when coadministered with strong CYP3A4 inhibitors.
- pacritinib
isoniazid will decrease the level or effect of pacritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- palbociclib
isoniazid will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of palbociclib with strong CYP3A inhibitors. If unable to avoid, reduce palbociclib dose to 75 mg/day.
- pemigatinib
isoniazid 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.
- pexidartinib
isoniazid 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.
isoniazid and pexidartinib both increase inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity. - phenelzine
phenelzine and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug.
- pimavanserin
isoniazid will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease dose to 17 mg/day if pimavanserin is coadministered with strong CYP3A4 inhibitors.
- pimozide
isoniazid increases levels of pimozide by decreasing metabolism. Contraindicated. Risk of QT interval prolongation.
- pomalidomide
isoniazid increases levels of pomalidomide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ponatinib
isoniazid increases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease ponatinib starting dose to 30 mg qDay if coadministration with strong CYP3A4 inhibitors cannot be avoided.
- pralsetinib
isoniazid will increase the level or effect of pralsetinib by affecting hepatic enzyme CYP2E1 metabolism. Avoid or Use Alternate Drug.
- pretomanid
isoniazid, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.
- ranolazine
isoniazid will increase the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- red yeast rice
isoniazid will increase the level or effect of red yeast rice by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. May increase creatine kinase levels and increase risk of myopathy or rhabdomyolysis; red yeast rice contains monocolin K (reportedly identical to lovastatin)
- rifampin
rifampin increases toxicity of isoniazid by increasing metabolism. Avoid or Use Alternate Drug. Rifampin enhances the metabolism of isoniazid to hepatotoxic metabolites.
- rimegepant
isoniazid will increase the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- riociguat
isoniazid will increase the level or effect of riociguat by Other (see comment). Avoid or Use Alternate Drug. Coadministration of riociguat (an ABCG2 [BCRP] substrate) with strong ABCG2 inhibitors may require a decreased initial dose of 0.5 mg PO TID; monitor for signs of hypotension and reduce dose if needed
- ruxolitinib
isoniazid will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce ruxolitinib starting dose to 10 mg BID with platelet count 100 X 10^9/L or more and concurrent use of strong CYP3A4 inhibitors; avoid with platelet counts <100 X 10^9/L
- ruxolitinib topical
isoniazid will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce ruxolitinib starting dose to 10 mg BID with platelet count 100 X 10^9/L or more and concurrent use of strong CYP3A4 inhibitors; avoid with platelet counts <100 X 10^9/L
- selumetinib
isoniazid 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
isoniazid will increase the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- simvastatin
isoniazid will increase the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- siponimod
isoniazid 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
isoniazid will increase the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- sonidegib
isoniazid will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sonidegib with strong CYP3A4 inhibitors.
- suvorexant
isoniazid increases levels of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Suvorexant not recommended with use of strong CYP3A4 inhibitors.
- tamsulosin
isoniazid increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- tazemetostat
isoniazid 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).
- tofacitinib
isoniazid increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce tofacitinib dose to 5 mg qDay when coadministered with potent CYP3A4 inhibitors.
- tolvaptan
isoniazid will increase the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- trabectedin
isoniazid will increase the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If strong CYP3A inhibitor must be used, short-term (eg, less than 14 days), administer strong CYP3A inhibitor 1 week after trabectedin infusion, and discontinue the day prior to next trabectedin infusion
- tranylcypromine
tranylcypromine and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug.
- vemurafenib
isoniazid increases levels of vemurafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- vilazodone
isoniazid, vilazodone. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug. Concomitant therapy should be discontinued immediately if signs or symptoms of serotonin syndrome emerge and supportive symptomatic treatment should be initiated. .
isoniazid increases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors may increase vilazodone plasma levels by 50% - Reduce daily dose to 20 mg. - vorapaxar
isoniazid increases levels of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
Monitor Closely (262)
- 5-HTP
5-HTP and isoniazid both increase serotonin levels. Use Caution/Monitor.
- abemaciclib
isoniazid will increase the level or effect of abemaciclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A4 inhibitors increase plasma levels of abemaciclib and its metabolites. Abemaciclib dose reduction required. If a strong CYP3A4 inhibitor is discontinued, increase abemaciclib to the dose prior to initiating the strong inhibitor.
- abrocitinib
isoniazid will increase the level or effect of abrocitinib by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Start abrocitinib 50 mg qDay when coadministered with CYP2C19 inhibitors. If adequate response not achieved after 12 weeks, may increase to 100 mg qDay. Discontinue if inadequate response after dosage increase.
- acetaminophen
isoniazid will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
- acetaminophen IV
isoniazid will increase the level or effect of acetaminophen IV by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
- acetaminophen rectal
isoniazid will increase the level or effect of acetaminophen rectal by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
- almotriptan
isoniazid will increase the level or effect of almotriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
almotriptan and isoniazid both increase serotonin levels. Use Caution/Monitor. - alosetron
isoniazid will increase the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- alprazolam
isoniazid will increase the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- aluminum hydroxide
aluminum hydroxide decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- amifampridine
isoniazid 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
isoniazid will increase the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- amitriptyline
isoniazid will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
amitriptyline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely. - amoxapine
amoxapine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- apalutamide
isoniazid will increase the level or effect of apalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of apalutamide with strong CYP3A4 or CYP2C8 inhibitors does not require initial dosage modification; however, dose reduction may be needed based on tolerability.
- aprepitant
isoniazid will increase the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- aripiprazole
isoniazid will increase the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- armodafinil
isoniazid will increase the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- artemether/lumefantrine
isoniazid will increase the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- atazanavir
isoniazid will increase the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- atogepant
isoniazid will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Recommended atogepant dosage is 10 mg PO qDay when coadministered with strong CYP3A4 inhibitors.
- atorvastatin
isoniazid will increase the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- belzutifan
isoniazid will increase the level or effect of belzutifan by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Belzutifan is a CYP2C19 substrate. Coadministration with CYP2C19 inhibitors may increase incidence or severity of adverse effects. Monitor for anemia and hypoxia and reduce belzutifan dose as recommended.
- benzhydrocodone/acetaminophen
isoniazid will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with strong CYP3A4 inhibitors may increase hydrocodone (benzhydrocodone is prodrug of hydrocodone) plasma concentrations and can result in potentially fatal respiratory depression.
- bexarotene
isoniazid will increase the level or effect of bexarotene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- bortezomib
isoniazid will increase the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- bosentan
isoniazid will increase the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- brentuximab vedotin
isoniazid increases levels of brentuximab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor patients for adverse reactions. .
- brexpiprazole
isoniazid will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Administer half of the usual brexpiprazole dose when coadministered with strong CYP3A4 inhibitors. If also administered with a strong/moderate CYP2D6 inhibitor, administer a quarter of brexpiprazole dose.
isoniazid will increase the level or effect of brexpiprazole by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP2D6 inhibitor PLUS a strong/moderate CYP3A4 inhibitor. - budesonide
isoniazid will increase the level or effect of budesonide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- buprenorphine subdermal implant
isoniazid 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
isoniazid 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
isoniazid will increase the level or effect of buspirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
buspirone and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely. - calcifediol
isoniazid, calcifediol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. CYP450 inhibitors may inhibit enzymes involved in vitamin D metabolism (CYP24A1 and CYP27B1). This may alter serum levels of calcifediol and decrease the conversion of calcifediol to calcitriol. Dose adjustment of calcifediol may be required, and serum 25hydroxyvitamin D, intact PTH, and serum calcium concentrations should be closely monitored when initiating or discontinuing a strong CYP3A4 inhibitor.
- calcium carbonate
calcium carbonate decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- cannabidiol
isoniazid 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 strong CYP3A4 inhibitor.
isoniazid will increase the level or effect of cannabidiol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a strong CYP2C19 inhibitor. - carbamazepine
isoniazid will increase the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor plasma levels when used concomitantly
- cariprazine
isoniazid will increase the level or effect of cariprazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with strong CYP3A4 inhibitors requires cariprazine dose reduction. See Dosage Modification section in drug monograph.
- cevimeline
isoniazid will increase the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cilostazol
isoniazid will increase the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cimetidine
isoniazid will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
- cinacalcet
isoniazid will increase the level or effect of cinacalcet by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- citalopram
isoniazid will increase the level or effect of citalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Citalopram 20 mg/day is the maximum recommended dose for patients taking CYP2C19 inhibitors because of the risk of QT prolongation.
- clarithromycin
isoniazid will increase the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- clobazam
isoniazid will increase the level or effect of clobazam by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Dosage adjustment may be required; CYP2C19 inhibitors may result in increased exposure to N-desmethylclobazam (active metabolite).
- clomipramine
clomipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- clopidogrel
isoniazid 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
- clorazepate
isoniazid will increase the level or effect of clorazepate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- clozapine
isoniazid will increase the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cobicistat
isoniazid will increase the level or effect of cobicistat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cocaine topical
cocaine topical and isoniazid both increase serotonin levels. Use Caution/Monitor.
- codeine
isoniazid decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
- cortisone
isoniazid will increase the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- crizotinib
isoniazid increases levels of crizotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Concomitant use of strong CYP3A inhibitors should be avoided. .
- cycloserine
isoniazid increases toxicity of cycloserine by decreasing metabolism. Use Caution/Monitor. Enhanced CNS toxicity; risk of seizure.
- dapsone
isoniazid will increase the level or effect of dapsone by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
isoniazid will increase the level or effect of dapsone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - daridorexant
isoniazid 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
isoniazid will increase the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- darunavir
isoniazid will increase the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- dasatinib
isoniazid will increase the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- deflazacort
isoniazid 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.
- desipramine
desipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- dexamethasone
isoniazid will increase the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- dexfenfluramine
dexfenfluramine and isoniazid both increase serotonin levels. Use Caution/Monitor.
- dextroamphetamine
dextroamphetamine and isoniazid both increase serotonin levels. Use Caution/Monitor.
- dextromethorphan
dextromethorphan and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- diazepam
isoniazid will increase the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
isoniazid will increase the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - diazepam intranasal
isoniazid will increase the level or effect of diazepam intranasal by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Strong or moderate CYP2C19 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.
isoniazid 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
dichlorphenamide, isoniazid. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Both drugs can cause metabolic acidosis.
- dienogest/estradiol valerate
isoniazid will increase the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for potential adverse effects such as nausea, irregular uterine bleeding, breast tenderness and headache.
- dihydroergotamine
dihydroergotamine and isoniazid both increase serotonin levels. Use Caution/Monitor.
- dihydroergotamine intranasal
dihydroergotamine intranasal and isoniazid both increase serotonin levels. Use Caution/Monitor.
- disopyramide
isoniazid will increase the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- disulfiram
disulfiram will increase the level or effect of isoniazid by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
isoniazid increases toxicity of disulfiram by decreasing metabolism. Use Caution/Monitor. Enhanced CNS toxicity. - docetaxel
isoniazid will increase the level or effect of docetaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- doravirine
isoniazid will increase the level or effect of doravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of doravirine and CYP3A4 inhibitors may increase plasma concentrations and toxicities of doravirine.
- doxepin
doxepin and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- doxorubicin
isoniazid will increase the level or effect of doxorubicin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- doxorubicin liposomal
isoniazid will increase the level or effect of doxorubicin liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- dronabinol
isoniazid will increase the level or effect of dronabinol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dronabinol is a CYP3A4 substrate.
- duloxetine
duloxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- dutasteride
isoniazid will increase the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- efavirenz
isoniazid will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- elagolix
isoniazid will increase the level or effect of elagolix by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of elagolix 200 mg BID with strong CYP3A inhibitors for >1 month is not recommended. Limit elagolix dose to 150 mg qDay and CYP3A inhibitor duration of use to 6 months if coadministered.
- eletriptan
isoniazid will increase the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
eletriptan and isoniazid both increase serotonin levels. Use Caution/Monitor. - eluxadoline
isoniazid increases levels of eluxadoline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. As a precautionary measure due to incomplete information on the metabolism of eluxadoline, use caution when coadministered with strong CYP2C19 inhibitors.
- elvitegravir
isoniazid increases levels of elvitegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Elvitegravir is a CYP3A4 substrate; if coadministered with strong CYP3A4 inhibitors may increase levels.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
isoniazid will increase the level or effect of elvitegravir/cobicistat/emtricitabine/tenofovir DF by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- enfortumab vedotin
isoniazid increases toxicity of enfortumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Enfortumab vedotin is an antibody-drug conjugate that releases monomethylauristatin E (MMAE) via proteolytic cleavage. MMAE is primarily metabolized by CYP3A4 in vitro. Coadministration with strong CYP3A4 inhibitors may increase free MMAE exposure, which may increase the incidence or severity of toxicities.
- ergotamine
ergotamine and isoniazid both increase serotonin levels. Use Caution/Monitor.
- erlotinib
isoniazid will increase the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- escitalopram
isoniazid will increase the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
escitalopram and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely. - estradiol vaginal
isoniazid will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase plasma concentrations of estrogens and toxicities.
- ethanol
isoniazid will increase the level or effect of ethanol by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor. Generally avoid; increased risk of hepatotoxicity
- ethionamide
ethionamide increases levels of isoniazid by unspecified interaction mechanism. Use Caution/Monitor.
- etonogestrel
isoniazid will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- etoposide
isoniazid will increase the level or effect of etoposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- etravirine
isoniazid will increase the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- felodipine
isoniazid will increase the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fenfluramine
fenfluramine and isoniazid both increase serotonin levels. Use Caution/Monitor.
- fesoterodine
isoniazid will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- finasteride
isoniazid will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- finerenone
isoniazid 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
isoniazid will increase the level or effect of flibanserin by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Coadministration of flibanserin with strong CYP2C19 inhibitors may increase flibanserin exposure and increase the risk of hypotension, syncope, and CNS depression.
- fludrocortisone
isoniazid will increase the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fluoxetine
fluoxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- fluticasone furoate
isoniazid will increase the level or effect of fluticasone furoate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposure
- fluticasone inhaled
isoniazid will increase the level or effect of fluticasone inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposure
- fluvoxamine
fluvoxamine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- fosamprenavir
isoniazid will increase the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fosaprepitant
isoniazid will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- frovatriptan
frovatriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.
- galantamine
isoniazid will increase the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- gefitinib
isoniazid increases levels of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of strong CYP3A4 inhibitors may increase risk for gefitinib adverse effects.
- gepirone
isoniazid will increase the level or effect of gepirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce gepirone dose by 50% when used concomitantly with a moderate CYP3A4 inhibitor.
gepirone and isoniazid both increase serotonin levels. Use Caution/Monitor. Monitor for symptoms of serotonin syndrome when gepirone is used gepirone with other drugs that may affect the serotonergic neurotransmitter systems. If serotonin syndrome occurs, consider discontinue gepirone and/or concomitant serotonergic drug. - glecaprevir/pibrentasvir
isoniazid will increase the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- green tea
green tea, isoniazid. Other (see comment). Use Caution/Monitor. Comment: Avoid combination or excessive consumption of green tea. Combination may increase risk of cardiac arrhythmias or severe hypertension can occur due to caffeine component of green tea.
- guanfacine
isoniazid 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.
- haloperidol
isoniazid will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- hydrocodone
isoniazid will increase the level or effect of hydrocodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with CYP3A4 inhibitors may increase hydrocodone plasma concentrations and can result in potentially fatal respiratory depression
- hydrocortisone
isoniazid will increase the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- hydroxyprogesterone caproate (DSC)
isoniazid will increase the level or effect of hydroxyprogesterone caproate (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- iloperidone
isoniazid will increase the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- imatinib
isoniazid will increase the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- imipramine
isoniazid will increase the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
imipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely. - indinavir
isoniazid will increase the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- insulin degludec
isoniazid decreases effects of insulin degludec by pharmacodynamic antagonism. Use Caution/Monitor. Isoniazid may increase blood glucose (rare).
- insulin degludec/insulin aspart
isoniazid decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Use Caution/Monitor. Isoniazid may increase blood glucose (rare).
- insulin inhaled
isoniazid decreases effects of insulin inhaled by pharmacodynamic antagonism. Use Caution/Monitor. Isoniazid may increase blood glucose (rare).
- isavuconazonium sulfate
isoniazid will decrease the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- isradipine
isoniazid will increase the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- istradefylline
isoniazid will increase the level or effect of istradefylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Do not exceed istradefylline 20 mg/day if coadministered with strong CYP3A4 inhibitors.
- itraconazole
isoniazid decreases levels of itraconazole by unspecified interaction mechanism. Use Caution/Monitor.
- ivacaftor
isoniazid will increase the level or effect of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce ivacaftor dose if coadministered with strong CYP3A4 inhibitors. See specific ivacaftor-containing product for precise dosage modification.
- ixabepilone
isoniazid will increase the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- L-tryptophan
isoniazid and L-tryptophan both increase serotonin levels. Use Caution/Monitor.
- lacosamide
isoniazid increases levels of lacosamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider decreasing lacosamide dose when coadministered with strong CYP3A4 inhibitors.
- lansoprazole
isoniazid will increase the level or effect of lansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
- lapatinib
isoniazid will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- levamlodipine
isoniazid 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.
- levodopa inhaled
isoniazid decreases effects of levodopa inhaled by altering metabolism. Use Caution/Monitor. Isoniazid may inhibit dopa-decarboxylase in the brain; thereby, preventing conversion of levodopa to active dopamine.
- levomilnacipran
levomilnacipran and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
isoniazid will increase the level or effect of levomilnacipran by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Do not exceed 80 mg/day of levomilnacipran when coadministered with strong CYP3A4 inhibitors - levonorgestrel oral/ethinylestradiol/ferrous bisglycinate
isoniazid will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.
- lithium
isoniazid and lithium both increase serotonin levels. Use Caution/Monitor.
- lofepramine
lofepramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- lopinavir
isoniazid will increase the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- loratadine
isoniazid will increase the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lsd
isoniazid and lsd both increase serotonin levels. Use Caution/Monitor.
- lumacaftor/ivacaftor
isoniazid increases levels of lumacaftor/ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A inhibitors do not impact lumacaftor exposure, but increased ivacaftor exposure by 4.3-fold. Due to the induction effect of lumacaftor on CYP3A, at steady-state the net exposure of ivacaftor is not expected to exceed that when given in the absence of lumacaftor at a dose of 150 mg q12hr (the approved dose of ivacaftor monotherapy). Therefore, no dose adjustment is necessary when CYP3A inhibitors are initiated in patients currently taking lumacaftor/ivacaftor. However, when initiating lumacaftor/ivacaftor in patients taking strong CYP3A inhibitors, reduce the dose to 1 tablet daily (lumacaftor 200 mg/ivacaftor 125 mg total daily dose) for the first week of treatment to allow for the steady-state induction effect of lumacaftor. Following this period, continue with the recommended daily dose. No dose adjustment is required for moderate or weak CYP3A4 inhibitors.
- lumateperone
isoniazid 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
isoniazid will increase the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- maprotiline
maprotiline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- maraviroc
isoniazid will increase the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Decrease maraviroc dose to 150 mg BID when coadministered with strong CYP3A4 inhibitors
- mavacamten
isoniazid 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.
- medroxyprogesterone
isoniazid will increase the level or effect of medroxyprogesterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- mefloquine
isoniazid will increase the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- meperidine
isoniazid and meperidine both increase serotonin levels. Modify Therapy/Monitor Closely.
- metformin
isoniazid decreases effects of metformin by unspecified interaction mechanism. Use Caution/Monitor. Patient should be closely observed for loss of blood glucose control; when drugs are withdrawn from a patient receiving metformin, patient should be observed closely for hypoglycemia.
- methadone
isoniazid will increase the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- methylprednisolone
isoniazid will increase the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- metronidazole
metronidazole will increase the level or effect of isoniazid by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
- midazolam
isoniazid will increase the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- milnacipran
milnacipran and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- mipomersen
mipomersen, isoniazid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.
- mirtazapine
isoniazid and mirtazapine both increase serotonin levels. Use Caution/Monitor.
- morphine
isoniazid and morphine both increase serotonin levels. Use Caution/Monitor.
- naldemedine
isoniazid 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.
- naratriptan
naratriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.
- nefazodone
nefazodone and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- nelfinavir
isoniazid will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- netupitant/palonosetron
isoniazid will increase the level or effect of netupitant/palonosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Netupitant is mainly metabolized by CYP3A4; no dosage adjustment is required
- nicardipine
isoniazid will increase the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nifedipine
isoniazid will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nimodipine
isoniazid will increase the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nitrendipine
isoniazid will increase the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- norgestrel
isoniazid will increase the level or effect of norgestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may increase systemic concentration of norgestrel, which may increase risk for adverse effects
- nortriptyline
nortriptyline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- oliceridine
isoniazid will increase the level or effect of oliceridine by affecting hepatic enzyme CYP2D6 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.
isoniazid 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. - ondansetron
isoniazid will increase the level or effect of ondansetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP-450 inhibitors may decrease clearance of ondansetron. However, no dosage adjustment for ondansetron is recommended
- osilodrostat
isoniazid will increase the level or effect of osilodrostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce dose of osilodrostat, a CYP3A4 substrate, by half when coadministered with a strong CYP3A4 inhibitor.
- ospemifene
isoniazid increases levels of ospemifene by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
isoniazid increases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - paclitaxel
isoniazid will increase the level or effect of paclitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- paclitaxel protein bound
isoniazid will increase the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- palovarotene
isoniazid will increase the level or effect of palovarotene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of palovarotene, a CYP3A substrate, with moderate CYP3A inhibitors. If unavoidable, reduce palovarotene dose by 50%.
- panobinostat
isoniazid increases levels of panobinostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce panobinostat starting dose to 10 mg if coadministered with strong CYP3A4 inhibitors.
- paroxetine
paroxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- pazopanib
isoniazid 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
- pentazocine
isoniazid and pentazocine both increase serotonin levels. Use Caution/Monitor.
- pimozide
isoniazid will increase the level or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- polatuzumab vedotin
isoniazid will increase the level or effect of polatuzumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Polatuzumab undergoes catabolism to small peptides, amino acids, monomethyl auristatin E (MMAE), and unconjugated MMAE-related catabolites. MMAE is a CYP3A4 substrate. Coadministration of polatuzumab vedotin with a strong CYP3A4 inhibitor may increase unconjugated MMAE AUC, which may increase polatuzumab vedotin toxicities.
- prednisolone
isoniazid will increase the level or effect of prednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- prednisone
isoniazid will increase the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- propafenone
isoniazid will increase the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- protriptyline
protriptyline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- quetiapine
isoniazid will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- quinidine
isoniazid will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- quinine
isoniazid will increase the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rasagiline
rasagiline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- repaglinide
isoniazid will increase the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rilpivirine
isoniazid increases levels of rilpivirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ripretinib
isoniazid will increase the level or effect of ripretinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with a strong CYP3A inhibitor will increase systemic exposure to ripretinib and its active metabolite (DP-5439), which may increase risk of adverse reactions.
- ritonavir
isoniazid will increase the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rizatriptan
rizatriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.
- romidepsin
isoniazid will increase the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- safinamide
isoniazid, safinamide. Either increases toxicity of the other by serotonin levels. Modify Therapy/Monitor Closely. Monitor for hypertension and reaction to dietary tyramine in patients treated concomitantly with isoniazid and safinamide.
- SAMe
isoniazid and SAMe both increase serotonin levels. Use Caution/Monitor.
- saquinavir
isoniazid will increase the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- saxagliptin
isoniazid will increase the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Limit saxagliptin dose to 2.5 mg/day when coadministered with strong CYP3A4 inhibitors
- selegiline
selegiline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- selegiline transdermal
selegiline transdermal and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- sertraline
sertraline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- sevoflurane
isoniazid will increase the level or effect of sevoflurane by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
- sildenafil
isoniazid will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- sodium bicarbonate
sodium bicarbonate decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- sodium citrate/citric acid
sodium citrate/citric acid decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- sodium picosulfate/magnesium oxide/anhydrous citric acid
isoniazid 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 sulfate/?magnesium sulfate/potassium chloride
sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of isoniazid by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
- sodium sulfate/potassium sulfate/magnesium sulfate
sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of isoniazid by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
- solifenacin
isoniazid will increase the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- St John's Wort
isoniazid and St John's Wort both increase serotonin levels. Modify Therapy/Monitor Closely.
- sufentanil
isoniazid will increase the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- sufentanil SL
isoniazid 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.
- sumatriptan
sumatriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.
- sumatriptan intranasal
sumatriptan intranasal and isoniazid both increase serotonin levels. Use Caution/Monitor.
- sunitinib
isoniazid will increase the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tacrolimus
isoniazid will increase the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tadalafil
isoniazid will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For ED limit tadalafil to max of 2.5 mg/day (for daily use) or 10 mg dose every 72 hr (for use as needed). Avoid concurrent use of tadalafil for pulmonary HTN in patients taking strong CYP3A4 inhibitors.
- tamoxifen
isoniazid, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).
- tamsulosin
isoniazid increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- tasimelteon
isoniazid will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- temsirolimus
isoniazid will increase the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- terbinafine
isoniazid will increase the level or effect of terbinafine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tezacaftor
isoniazid 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 strong CYP3A inhibitor.
- theophylline
isoniazid will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tipranavir
isoniazid will increase the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tisotumab vedotin
isoniazid increases levels of tisotumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tisotumab vedotin?s active metabolite (MMAE) is a CYP3A4 substrate. Coadministration with strong CYP3A4 inhibitors may increase unconjugated MMAE systemic exposure and increase risk of adverse effects.
- tofacitinib
isoniazid increases levels of tofacitinib by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. No specific dose adjustment recommended when tofacitinib coadministered with potent CYP2C19 inhibitors; decrease tofacitinib dose if coadministered with both moderate CYP3A4 and potent CYP2C19 inhibitors .
- tolterodine
isoniazid will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- toremifene
isoniazid increases levels of toremifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Metabolism of toremifene may be inhibited by drugs known to inhibit CYP3A4 hepatic enzymes.
- tramadol
isoniazid and tramadol both increase serotonin levels. Use Caution/Monitor.
- trazodone
isoniazid will increase the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
trazodone and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely. - triamcinolone acetonide injectable suspension
isoniazid will increase the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- triazolam
isoniazid will increase the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- trimipramine
trimipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- ubrogepant
isoniazid will decrease the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Dose adjustment is recommended with concomitant use of ubrogepant and moderate and weak CYP3A4 inducers. (see Dosage Modifications)
- umeclidinium bromide/vilanterol inhaled
isoniazid will increase the level or effect of umeclidinium bromide/vilanterol inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Vilanterol is a CYP3A4 substrate; coadministration with potent CYP3A4 inhibitors may increase systemic exposure
- upadacitinib
isoniazid will increase the level or effect of upadacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution if upadacitinib is coadministered with strong CYP3A4 inhibitors.
- valbenazine
isoniazid will increase the level or effect of valbenazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce valbenazine dose to 40 mg once daily when coadministered with a strong CYP3A4 inhibitor.
- valoctocogene roxaparvovec
isoniazid and valoctocogene roxaparvovec both increase Other (see comment). Use Caution/Monitor. Medications that may cause hepatotoxicity when combined with valoctogene roxaparvovec may potentiate the risk of elevated liver enzymes. Closely monitor these medications and consider alternative medications in case of potential drug interactions.
- vardenafil
isoniazid 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
- venlafaxine
venlafaxine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
- verapamil
isoniazid will increase the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- vilanterol/fluticasone furoate inhaled
isoniazid will increase the level or effect of vilanterol/fluticasone furoate inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Fluticasone furoate and vilanterol are both CYP3A4 substrates; coadministration with potent CYP3A4 inhibitors may increase systemic exposure
- vinblastine
isoniazid will increase the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- vincristine
isoniazid will increase the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- vincristine liposomal
isoniazid will increase the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- vinorelbine
isoniazid will increase the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- voriconazole
isoniazid will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
- warfarin
isoniazid will increase the level or effect of warfarin by Other (see comment). Use Caution/Monitor. Warfarin's less potent R-enantiomer is metabolized in part by CYP3A4 (and also CYP1A2 and CYP2C19). Monitor INR more frequently if coadministered with inhibitors of these isoenzymes and adjust warfarin dose if needed.
- zanubrutinib
isoniazid 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.
- zolmitriptan
zolmitriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.
- zonisamide
isoniazid will increase the level or effect of zonisamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
Minor (77)
- acarbose
isoniazid decreases effects of acarbose by unspecified interaction mechanism. Minor/Significance Unknown.
- acetaminophen
isoniazid increases toxicity of acetaminophen by unknown mechanism. Minor/Significance Unknown.
- acetaminophen IV
isoniazid increases toxicity of acetaminophen IV by unknown mechanism. Minor/Significance Unknown.
- acetaminophen rectal
isoniazid increases toxicity of acetaminophen rectal by unknown mechanism. Minor/Significance Unknown.
- ambrisentan
isoniazid will increase the level or effect of ambrisentan by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
isoniazid will increase the level or effect of ambrisentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. - amitriptyline
isoniazid will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- bazedoxifene/conjugated estrogens
isoniazid will increase the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- budesonide
budesonide decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.
- calcium acetate
isoniazid decreases levels of calcium acetate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- calcium carbonate
isoniazid decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- calcium chloride
isoniazid decreases levels of calcium chloride by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- calcium citrate
isoniazid decreases levels of calcium citrate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- calcium gluconate
isoniazid decreases levels of calcium gluconate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- chlorpropamide
isoniazid decreases effects of chlorpropamide by unspecified interaction mechanism. Minor/Significance Unknown.
- clomipramine
isoniazid will increase the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- conjugated estrogens
isoniazid will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- conjugated estrogens, vaginal
isoniazid will increase the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- cortisone
cortisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.
- deflazacort
deflazacort decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.
- dexamethasone
dexamethasone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.
- didanosine
didanosine, isoniazid. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Enhanced risk of peripheral neuropathy.
- donepezil
isoniazid will increase the level or effect of donepezil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- estradiol
isoniazid will increase the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- estrogens conjugated synthetic
isoniazid will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- estrogens esterified
isoniazid will increase the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- estropipate
isoniazid will increase the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- ethanol
isoniazid increases toxicity of ethanol by decreasing metabolism. Minor/Significance Unknown. Enhanced hepatotoxicity.
- ethotoin
isoniazid increases levels of ethotoin by decreasing metabolism. Minor/Significance Unknown.
- eucalyptus
isoniazid will increase the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- fludrocortisone
fludrocortisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.
- food
food decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- fosphenytoin
isoniazid increases levels of fosphenytoin by decreasing metabolism. Minor/Significance Unknown.
- ganaxolone
isoniazid, ganaxolone. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. Changes in ganaxolone exposures when coadministered with strong, moderate, or weak CYP3A4 inhibitors are not expected to be clinically significant.
- glimepiride
isoniazid decreases effects of glimepiride by unspecified interaction mechanism. Minor/Significance Unknown.
- glipizide
isoniazid decreases effects of glipizide by unspecified interaction mechanism. Minor/Significance Unknown.
- glyburide
isoniazid decreases effects of glyburide by unspecified interaction mechanism. Minor/Significance Unknown.
- hydrocortisone
hydrocortisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.
- imipramine
isoniazid will increase the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- insulin aspart
isoniazid decreases effects of insulin aspart by unspecified interaction mechanism. Minor/Significance Unknown.
- insulin detemir
isoniazid decreases effects of insulin detemir by unspecified interaction mechanism. Minor/Significance Unknown.
- insulin glargine
isoniazid decreases effects of insulin glargine by unspecified interaction mechanism. Minor/Significance Unknown.
- insulin glulisine
isoniazid decreases effects of insulin glulisine by unspecified interaction mechanism. Minor/Significance Unknown.
- insulin lispro
isoniazid decreases effects of insulin lispro by unspecified interaction mechanism. Minor/Significance Unknown.
- insulin NPH
isoniazid decreases effects of insulin NPH by unspecified interaction mechanism. Minor/Significance Unknown.
- insulin regular human
isoniazid decreases effects of insulin regular human by unspecified interaction mechanism. Minor/Significance Unknown.
- ixazomib
isoniazid, ixazomib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. In clinical trials, coadministration of ixazomib with strong CYP3A inhibitors did not result in a clinically meaningful change in the systemic exposure of ixazomib.
- ketoconazole
isoniazid will increase the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- levoketoconazole
isoniazid will increase the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- mestranol
isoniazid will increase the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- methylprednisolone
methylprednisolone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.
- miglitol
isoniazid decreases effects of miglitol by unspecified interaction mechanism. Minor/Significance Unknown.
- montelukast
isoniazid will increase the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- nateglinide
isoniazid decreases effects of nateglinide by unspecified interaction mechanism. Minor/Significance Unknown.
- niacin
isoniazid decreases levels of niacin by pharmacodynamic antagonism. Minor/Significance Unknown.
- oxybutynin
isoniazid will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- parecoxib
isoniazid will increase the level or effect of parecoxib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- phenytoin
isoniazid increases levels of phenytoin by decreasing metabolism. Minor/Significance Unknown.
- pioglitazone
isoniazid will increase the level or effect of pioglitazone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
isoniazid decreases effects of pioglitazone by unspecified interaction mechanism. Minor/Significance Unknown. - prednisolone
prednisolone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.
- prednisone
prednisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.
- primaquine
primaquine, isoniazid. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hemolysis in G6PD deficient pts.
- pyrazinamide
isoniazid, pyrazinamide. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive hepatotoxicity.
- pyridoxine
isoniazid decreases levels of pyridoxine by unspecified interaction mechanism. Minor/Significance Unknown. If INH dose >10 mg/kg/day, supplement 50 100mg pyridoxine/day.
- pyridoxine (Antidote)
isoniazid decreases levels of pyridoxine (Antidote) by unspecified interaction mechanism. Minor/Significance Unknown. If INH dose >10 mg/kg/day, supplement 50 100mg pyridoxine/day.
- rabeprazole
isoniazid will increase the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
- ramelteon
isoniazid will increase the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- repaglinide
isoniazid decreases effects of repaglinide by unspecified interaction mechanism. Minor/Significance Unknown.
- rosiglitazone
isoniazid decreases effects of rosiglitazone by unspecified interaction mechanism. Minor/Significance Unknown.
- sitagliptin
isoniazid decreases effects of sitagliptin by unspecified interaction mechanism. Minor/Significance Unknown.
- tolazamide
isoniazid decreases effects of tolazamide by unspecified interaction mechanism. Minor/Significance Unknown.
- tolbutamide
isoniazid decreases effects of tolbutamide by unspecified interaction mechanism. Minor/Significance Unknown.
- triamcinolone acetonide injectable suspension
triamcinolone acetonide injectable suspension decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.
- valproic acid
isoniazid increases levels of valproic acid by decreasing metabolism. Minor/Significance Unknown.
- vildagliptin
isoniazid decreases effects of vildagliptin by unspecified interaction mechanism. Minor/Significance Unknown.
- zaleplon
isoniazid will increase the level or effect of zaleplon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- ziprasidone
isoniazid will increase the level or effect of ziprasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- zolpidem
isoniazid will increase the level or effect of zolpidem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
Adverse Effects
>10%
Mild incr LFTs (10-20%)
Peripheral neuropathy (dose-related incidence, 10-20% incidence with 10 mg/kg/d)
Loss of appetite
Nausea
Vomiting
Stomach pain
Weakness
1-10%
Dizziness
Slurred speech
Lethargy
Progressive liver damage (increases with age; 2.3% in pts > 50 yo)
Hyperreflexia
<1%
Agranulocytosis
Anemia
Megaloblastic anemia
Thrombocytopenia
Systemic lupus erythematosus
Seizure
- other adverse reactions reported: pancreatitis; toxic epidermal necrolysis, and drug reaction with eosinophilia syndrome(DRESS)
Warnings
Black Box Warnings
Severe and sometimes fatal hepatitis may occur within the first 3 months of treatment and many months after treatment. Risk is related to age and increased with daily alcohol consumption.
Patients should be instructed about signs and symptoms of hepatitis.
Contraindications
Prev INH hepatic injury or reaction; acute liver dz; pancreatitis
Hypersensitivity
• Isoniazid is contraindicated in patients who develop severe hypersensitivity reactions, including drug-induced hepatitis; previous isoniazid-associated hepatic injury; severe adverse reactions to isoniazid such as drug fever, chills, arthritis; and acute liver disease of any etiology
Cautions
Alcohol or illicit injectable drug use, predisposition to neuropathy, malnourished, severe renal impairment, chronic liver dz
Use w/ other anti-TB agents
Give pyridoxine (B6) concurrently for pregnant women, malnourished pts. or those with neuropathic diathesis
Alcohol use, renal or hepatic dysfunction will affect serum levels
Pregnancy & Lactation
Pregnancy Category: C
Lactation: distributed into milk but safe for nursing infants
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Unknown: prob. inhibits cell-wall biosynthesis by interfering with lipid and DNA synthesis (bactericidal)
Absorption
Rapid and complete; rate can be slowed with food Peak Plasma Time: 1-2 hr
Distribution
All body tissues and fluids including CSF; crosses placenta; enters breast milk
Protein Bound: 10-15%
Metabolism
Hepatic with decay rate determined genetically by acetylation phenotype
Elimination
Half-life elimination: fast acetylators: 30-100 min; slow acetylators: 2-5 hr; may be prolonged with hepatic or severe renal impairment
Excretion: Urine (75-95%); feces
Administration
IM Preparation
At low temperatures, isoniazid in solution tends to crystallize; warm injection to room temperature to redissolve crystals prior to use
IM Administration
May be given by IM injection when oral therapy is not possible
Storage
Protect from light
Store at <40°C, preferably between 15-30°C
Protect from freezing
Images
BRAND | FORM. | UNIT PRICE | PILL IMAGE |
---|---|---|---|
isoniazid oral - | 300 mg tablet | ![]() | |
isoniazid oral - | 300 mg tablet | ![]() | |
isoniazid oral - | 100 mg tablet | ![]() | |
isoniazid oral - | 50 mg/5 mL solution | ![]() | |
isoniazid oral - | 300 mg tablet | ![]() | |
isoniazid oral - | 100 mg tablet | ![]() |
Copyright © 2010 First DataBank, Inc.
Patient Handout
isoniazid injection
NO MONOGRAPH AVAILABLE AT THIS TIME
USES: Consult your pharmacist.
HOW TO USE: Consult your pharmacist.
SIDE EFFECTS: Consult your pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: Consult your pharmacist.
DRUG INTERACTIONS: Consult your pharmacist.Keep a list of all your medications with you, and share the list with your doctor and pharmacist.
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
NOTES: No monograph available at this time.
MISSED DOSE: Consult your pharmacist.
STORAGE: Consult your pharmacist.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised July 2016. Copyright(c) 2023 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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