erythromycin base/sulfisoxazole (Rx)

Not prescribed for adults

H. influenzae Acute Otitis Media

<2 months: Contraindicated

>2 months: 50 mg/kg/day (erythromycin) or 150 mg/kg/day (sulfisoxazole) PO divided q6-8hr for10 days  

Not to exceed 6 g/day sulfisoxazole

Contraindicated (0)

Serious - Use Alternative (27)

• aminobenzoate potassium

  aminobenzoate potassium decreases effects of sulfisoxazole by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• aminolevulinic acid oral

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

• aminolevulinic acid topical

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

• antithrombin alfa

  sulfisoxazole increases effects of antithrombin alfa by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of antithrombin alfa by plasma protein binding competition. Avoid or Use Alternate Drug.

• antithrombin III

  sulfisoxazole increases effects of antithrombin III by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of antithrombin III by plasma protein binding competition. Avoid or Use Alternate Drug.

• argatroban

  sulfisoxazole increases effects of argatroban by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of argatroban by plasma protein binding competition. Avoid or Use Alternate Drug.

• BCG vaccine live

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

• bemiparin

  sulfisoxazole increases effects of bemiparin by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of bemiparin by plasma protein binding competition. Avoid or Use Alternate Drug.

• bivalirudin

  sulfisoxazole increases effects of bivalirudin by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of bivalirudin by plasma protein binding competition. Avoid or Use Alternate Drug.

• cholera vaccine

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

• dabrafenib

  sulfisoxazole increases levels of dabrafenib by decreasing metabolism. Avoid or Use Alternate Drug. Strong CYP2C8 inhibitors may increase dabrafenib levels.

• dalteparin

  sulfisoxazole increases effects of dalteparin by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of dalteparin by plasma protein binding competition. Avoid or Use Alternate Drug.

• enoxaparin

  sulfisoxazole increases effects of enoxaparin by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of enoxaparin by plasma protein binding competition. Avoid or Use Alternate Drug.

• fondaparinux

  sulfisoxazole increases effects of fondaparinux by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of fondaparinux by plasma protein binding competition. Avoid or Use Alternate Drug.

• heparin

  sulfisoxazole increases effects of heparin by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of heparin by plasma protein binding competition. Avoid or Use Alternate Drug.

• ivosidenib

  ivosidenib will decrease the level or effect of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2C9 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

• methenamine

  methenamine, sulfisoxazole. Other (see comment). Contraindicated. Comment: This combination may form an insoluble precipitate in the urine, decreasing the effects of both agents.

• methotrexate

  sulfisoxazole increases toxicity of methotrexate by plasma protein binding competition. Avoid or Use Alternate Drug.

• methyl aminolevulinate

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

• microbiota oral

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

• pexidartinib

  sulfisoxazole and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.

• phenindione

  sulfisoxazole increases effects of phenindione by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of phenindione by plasma protein binding competition. Avoid or Use Alternate Drug.

• pretomanid

  sulfisoxazole, 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.

• protamine

  sulfisoxazole increases effects of protamine by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of protamine by plasma protein binding competition. Avoid or Use Alternate Drug.

• tretinoin

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

• tretinoin topical

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

• typhoid vaccine live

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

Monitor Closely (47)

• alpelisib

  alpelisib will decrease the level or effect of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely.

• bazedoxifene/conjugated estrogens

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

• bupivacaine implant

  sulfisoxazole, bupivacaine implant. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Local anesthetics may increase the risk of developing methemoglobinemia when concurrently exposed to drugs that also cause methemoglobinemia.

• cannabidiol

  cannabidiol will increase the level or effect of sulfisoxazole by decreasing metabolism. Modify Therapy/Monitor Closely. Cannabidiol may potentially inhibit CYP2C9 activity. Consider reducing the dose when concomitantly using CYP2C9 substrates.

• chlorpropamide

  sulfisoxazole increases levels of chlorpropamide by plasma protein binding competition. Use Caution/Monitor.

• conjugated estrogens

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

• cyclosporine

  sulfisoxazole will decrease the level or effect of cyclosporine by unknown mechanism. Use Caution/Monitor.

• dapsone topical

  sulfisoxazole increases toxicity of dapsone topical by decreasing metabolism. Modify Therapy/Monitor Closely. May induce methemoglobinemia .

• digoxin

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

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  elvitegravir/cobicistat/emtricitabine/tenofovir DF decreases levels of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Elvitegravir is a moderate CYP2C9 inducer.

• estradiol

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

• estrogens conjugated synthetic

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

• estropipate

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

• ethinylestradiol

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

• glimepiride

  sulfisoxazole increases levels of glimepiride by plasma protein binding competition. Use Caution/Monitor.

• glipizide

  sulfisoxazole increases levels of glipizide by plasma protein binding competition. Use Caution/Monitor.

• glyburide

  sulfisoxazole increases levels of glyburide by plasma protein binding competition. Use Caution/Monitor.

• insulin aspart

  sulfisoxazole increases effects of insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin aspart protamine/insulin aspart

  sulfisoxazole increases effects of insulin aspart protamine/insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin degludec

  sulfisoxazole, insulin degludec. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  sulfisoxazole increases effects of insulin degludec by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin degludec/insulin aspart

  sulfisoxazole, insulin degludec/insulin aspart. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.

• insulin detemir

  sulfisoxazole increases effects of insulin detemir by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin glargine

  sulfisoxazole increases effects of insulin glargine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin glulisine

  sulfisoxazole increases effects of insulin glulisine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin inhaled

  sulfisoxazole, insulin inhaled. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  sulfisoxazole increases effects of insulin inhaled by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin isophane human/insulin regular human

  sulfisoxazole increases effects of insulin isophane human/insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin lispro

  sulfisoxazole increases effects of insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin lispro protamine/insulin lispro

  sulfisoxazole increases effects of insulin lispro protamine/insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin NPH

  sulfisoxazole increases effects of insulin NPH by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin regular human

  sulfisoxazole increases effects of insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

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

• lumacaftor/ivacaftor

  lumacaftor/ivacaftor, sulfisoxazole. affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2C9 substrates. .

• mestranol

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

• methoxsalen

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

• nateglinide

  sulfisoxazole increases levels of nateglinide by plasma protein binding competition. Use Caution/Monitor.

• nitisinone

  nitisinone will increase the level or effect of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Nitisinone inhibits CYP2C9. Caution if CYP2C9 substrate coadministered, particularly those with a narrow therapeutic index.

• paclitaxel

  sulfisoxazole will increase the level or effect of paclitaxel by Other (see comment). Modify Therapy/Monitor Closely. Paclitaxel levels/toxicity may increase when coadministered with CYP2C8 inhibitors

• paclitaxel protein bound

  sulfisoxazole will increase the level or effect of paclitaxel protein bound by Other (see comment). Modify Therapy/Monitor Closely. Paclitaxel levels/toxicity may increase when coadministered with CYP2C8 inhibitors

• promazine

  promazine increases toxicity of sulfisoxazole by unspecified interaction mechanism. Use Caution/Monitor. Enhanced myelosuppression.

• repaglinide

  sulfisoxazole increases levels of repaglinide by plasma protein binding competition. Use Caution/Monitor.

• rucaparib

  rucaparib will increase the level or effect of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP2C9 substrates, if clinically indicated.

• sparsentan

  sparsentan will decrease the level or effect of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Sparsentan (a CYP2C9 inducer) decreases exposure of CYP2C9 substrates and reduces efficacy related to these substrates.

• tetracaine

  tetracaine, sulfisoxazole. Other (see comment). Use Caution/Monitor. Comment: Monitor for signs of methemoglobinemia when methemoglobin-inducing drugs are coadministered.

• tolazamide

  sulfisoxazole increases levels of tolazamide by plasma protein binding competition. Use Caution/Monitor.

• tolbutamide

  sulfisoxazole increases levels of tolbutamide by plasma protein binding competition. Use Caution/Monitor.

• valoctocogene roxaparvovec

  sulfisoxazole 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.

• voclosporin

  voclosporin, sulfisoxazole. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.

Minor (49)

• amiloride

  amiloride increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• aminohippurate sodium

  sulfisoxazole, aminohippurate sodium. Other (see comment). Minor/Significance Unknown. Comment: This substance interferes with chemical color development of aminohippurate (PAH) essential to accurate renal clearance analysis.

• aspirin

  aspirin increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• aspirin rectal

  aspirin rectal increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• aspirin/citric acid/sodium bicarbonate

  aspirin/citric acid/sodium bicarbonate increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• balsalazide

  sulfisoxazole will decrease the level or effect of balsalazide by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  balsalazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• bendroflumethiazide

  bendroflumethiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• biotin

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

• bumetanide

  bumetanide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• chlorothiazide

  chlorothiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• chlorthalidone

  chlorthalidone increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• choline magnesium trisalicylate

  choline magnesium trisalicylate increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• cyclopenthiazide

  cyclopenthiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• diflunisal

  diflunisal increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• drospirenone

  drospirenone increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• ethacrynic acid

  ethacrynic acid increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• ethotoin

  sulfisoxazole increases levels of ethotoin by decreasing metabolism. Minor/Significance Unknown.

• fosphenytoin

  sulfisoxazole increases levels of fosphenytoin by decreasing metabolism. Minor/Significance Unknown.

• furosemide

  furosemide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• hydrochlorothiazide

  hydrochlorothiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• indapamide

  indapamide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• indomethacin

  indomethacin increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• isocarboxazid

  isocarboxazid increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• linezolid

  linezolid increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• mesalamine

  mesalamine increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• methohexital

  sulfisoxazole increases levels of methohexital by plasma protein binding competition. Minor/Significance Unknown.

• methyclothiazide

  methyclothiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• metolazone

  metolazone increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• mineral oil

  mineral oil decreases levels of sulfisoxazole by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• niacin

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

• pantothenic acid

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

• phenelzine

  phenelzine increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• phenytoin

  sulfisoxazole increases levels of phenytoin by decreasing metabolism. Minor/Significance Unknown.

• primaquine

  primaquine, sulfisoxazole. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hemolysis in G6PD deficient pts.

• probenecid

  probenecid increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• pyridoxine

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

• pyridoxine (Antidote)

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

• pyrimethamine

  sulfisoxazole, pyrimethamine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased bone marrow toxicity.

• salicylates (non-asa)

  salicylates (non-asa) increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• salsalate

  salsalate increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• selegiline transdermal

  selegiline transdermal increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• spironolactone

  spironolactone increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• sulfasalazine

  sulfasalazine increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• thiamine

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

• torsemide

  torsemide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• tranylcypromine

  tranylcypromine increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• triamterene

  triamterene increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• verteporfin

  sulfisoxazole, verteporfin. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased phototoxicity.

• willow bark

  willow bark increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• alpelisib

  Monitor Closely (1)alpelisib will decrease the level or effect of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely.

• amiloride

  Minor (1)amiloride increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• aminobenzoate potassium

  Serious - Use Alternative (1)aminobenzoate potassium decreases effects of sulfisoxazole by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

• aminohippurate sodium

  Minor (1)sulfisoxazole, aminohippurate sodium. Other (see comment). Minor/Significance Unknown. Comment: This substance interferes with chemical color development of aminohippurate (PAH) essential to accurate renal clearance analysis.

• aminolevulinic acid oral

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

• aminolevulinic acid topical

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

• antithrombin alfa

  Serious - Use Alternative (2)sulfisoxazole increases effects of antithrombin alfa by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of antithrombin alfa by plasma protein binding competition. Avoid or Use Alternate Drug.

• antithrombin III

  Serious - Use Alternative (2)sulfisoxazole increases effects of antithrombin III by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of antithrombin III by plasma protein binding competition. Avoid or Use Alternate Drug.

• argatroban

  Serious - Use Alternative (2)sulfisoxazole increases effects of argatroban by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of argatroban by plasma protein binding competition. Avoid or Use Alternate Drug.

• aspirin

  Minor (1)aspirin increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• aspirin rectal

  Minor (1)aspirin rectal increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• aspirin/citric acid/sodium bicarbonate

  Minor (1)aspirin/citric acid/sodium bicarbonate increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• balsalazide

  Minor (2)sulfisoxazole will decrease the level or effect of balsalazide by altering intestinal flora. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  balsalazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• bazedoxifene/conjugated estrogens

  Monitor Closely (1)sulfisoxazole will decrease the level or effect of bazedoxifene/conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• BCG vaccine live

  Serious - Use Alternative (1)sulfisoxazole decreases effects of BCG vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.

• bemiparin

  Serious - Use Alternative (2)sulfisoxazole increases effects of bemiparin by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of bemiparin by plasma protein binding competition. Avoid or Use Alternate Drug.

• bendroflumethiazide

  Minor (1)bendroflumethiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• biotin

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

• bivalirudin

  Serious - Use Alternative (2)sulfisoxazole increases effects of bivalirudin by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of bivalirudin by plasma protein binding competition. Avoid or Use Alternate Drug.

• bumetanide

  Minor (1)bumetanide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• bupivacaine implant

  Monitor Closely (1)sulfisoxazole, bupivacaine implant. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Local anesthetics may increase the risk of developing methemoglobinemia when concurrently exposed to drugs that also cause methemoglobinemia.

• cannabidiol

  Monitor Closely (1)cannabidiol will increase the level or effect of sulfisoxazole by decreasing metabolism. Modify Therapy/Monitor Closely. Cannabidiol may potentially inhibit CYP2C9 activity. Consider reducing the dose when concomitantly using CYP2C9 substrates.

• chlorothiazide

  Minor (1)chlorothiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• chlorpropamide

  Monitor Closely (1)sulfisoxazole increases levels of chlorpropamide by plasma protein binding competition. Use Caution/Monitor.

• chlorthalidone

  Minor (1)chlorthalidone increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• cholera vaccine

  Serious - Use Alternative (1)sulfisoxazole, cholera vaccine. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid coadministration of cholera vaccine with systemic antibiotics since these agents may be active against the vaccine strain. Do not administer cholera vaccine to patients who have received oral or parenteral antibiotics within 14 days prior to vaccination.

• choline magnesium trisalicylate

  Minor (1)choline magnesium trisalicylate increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• conjugated estrogens

  Monitor Closely (1)sulfisoxazole will decrease the level or effect of conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• cyclopenthiazide

  Minor (1)cyclopenthiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• cyclosporine

  Monitor Closely (1)sulfisoxazole will decrease the level or effect of cyclosporine by unknown mechanism. Use Caution/Monitor.

• dabrafenib

  Serious - Use Alternative (1)sulfisoxazole increases levels of dabrafenib by decreasing metabolism. Avoid or Use Alternate Drug. Strong CYP2C8 inhibitors may increase dabrafenib levels.

• dalteparin

  Serious - Use Alternative (2)sulfisoxazole increases effects of dalteparin by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of dalteparin by plasma protein binding competition. Avoid or Use Alternate Drug.

• dapsone topical

  Monitor Closely (1)sulfisoxazole increases toxicity of dapsone topical by decreasing metabolism. Modify Therapy/Monitor Closely. May induce methemoglobinemia .

• diflunisal

  Minor (1)diflunisal increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• digoxin

  Monitor Closely (1)sulfisoxazole will increase the level or effect of digoxin by altering intestinal flora. Applies only to oral form of both agents. Use Caution/Monitor.

• drospirenone

  Minor (1)drospirenone increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  Monitor Closely (1)elvitegravir/cobicistat/emtricitabine/tenofovir DF decreases levels of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Elvitegravir is a moderate CYP2C9 inducer.

• enoxaparin

  Serious - Use Alternative (2)sulfisoxazole increases effects of enoxaparin by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of enoxaparin by plasma protein binding competition. Avoid or Use Alternate Drug.

• estradiol

  Monitor Closely (1)sulfisoxazole will decrease the level or effect of estradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• estrogens conjugated synthetic

  Monitor Closely (1)sulfisoxazole will decrease the level or effect of estrogens conjugated synthetic by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• estropipate

  Monitor Closely (1)sulfisoxazole will decrease the level or effect of estropipate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• ethacrynic acid

  Minor (1)ethacrynic acid increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• ethinylestradiol

  Monitor Closely (1)sulfisoxazole will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• ethotoin

  Minor (1)sulfisoxazole increases levels of ethotoin by decreasing metabolism. Minor/Significance Unknown.

• fondaparinux

  Serious - Use Alternative (2)sulfisoxazole increases effects of fondaparinux by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of fondaparinux by plasma protein binding competition. Avoid or Use Alternate Drug.

• fosphenytoin

  Minor (1)sulfisoxazole increases levels of fosphenytoin by decreasing metabolism. Minor/Significance Unknown.

• furosemide

  Minor (1)furosemide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• glimepiride

  Monitor Closely (1)sulfisoxazole increases levels of glimepiride by plasma protein binding competition. Use Caution/Monitor.

• glipizide

  Monitor Closely (1)sulfisoxazole increases levels of glipizide by plasma protein binding competition. Use Caution/Monitor.

• glyburide

  Monitor Closely (1)sulfisoxazole increases levels of glyburide by plasma protein binding competition. Use Caution/Monitor.

• heparin

  Serious - Use Alternative (2)sulfisoxazole increases effects of heparin by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of heparin by plasma protein binding competition. Avoid or Use Alternate Drug.

• hydrochlorothiazide

  Minor (1)hydrochlorothiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• indapamide

  Minor (1)indapamide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• indomethacin

  Minor (1)indomethacin increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin aspart

  Monitor Closely (1)sulfisoxazole increases effects of insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin aspart protamine/insulin aspart

  Monitor Closely (1)sulfisoxazole increases effects of insulin aspart protamine/insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin degludec

  Monitor Closely (2)sulfisoxazole increases effects of insulin degludec by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.
  
  sulfisoxazole, insulin degludec. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.

• insulin degludec/insulin aspart

  Monitor Closely (1)sulfisoxazole, insulin degludec/insulin aspart. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.

• insulin detemir

  Monitor Closely (1)sulfisoxazole increases effects of insulin detemir by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin glargine

  Monitor Closely (1)sulfisoxazole increases effects of insulin glargine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin glulisine

  Monitor Closely (1)sulfisoxazole increases effects of insulin glulisine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin inhaled

  Monitor Closely (2)sulfisoxazole increases effects of insulin inhaled by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.
  
  sulfisoxazole, insulin inhaled. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.

• insulin isophane human/insulin regular human

  Monitor Closely (1)sulfisoxazole increases effects of insulin isophane human/insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin lispro

  Monitor Closely (1)sulfisoxazole increases effects of insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin lispro protamine/insulin lispro

  Monitor Closely (1)sulfisoxazole increases effects of insulin lispro protamine/insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin NPH

  Monitor Closely (1)sulfisoxazole increases effects of insulin NPH by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• insulin regular human

  Monitor Closely (1)sulfisoxazole increases effects of insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and sulfonamide antibiotics may require insulin dosage adjustment and increased glucose monitoring.

• isocarboxazid

  Minor (1)isocarboxazid increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• ivosidenib

  Serious - Use Alternative (1)ivosidenib will decrease the level or effect of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2C9 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  Monitor Closely (1)sulfisoxazole will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.

• linezolid

  Minor (1)linezolid increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• lumacaftor/ivacaftor

  Monitor Closely (1)lumacaftor/ivacaftor, sulfisoxazole. affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2C9 substrates. .

• mesalamine

  Minor (1)mesalamine increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• mestranol

  Monitor Closely (1)sulfisoxazole will decrease the level or effect of mestranol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

• methenamine

  Serious - Use Alternative (1)methenamine, sulfisoxazole. Other (see comment). Contraindicated. Comment: This combination may form an insoluble precipitate in the urine, decreasing the effects of both agents.

• methohexital

  Minor (1)sulfisoxazole increases levels of methohexital by plasma protein binding competition. Minor/Significance Unknown.

• methotrexate

  Serious - Use Alternative (1)sulfisoxazole increases toxicity of methotrexate by plasma protein binding competition. Avoid or Use Alternate Drug.

• methoxsalen

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

• methyclothiazide

  Minor (1)methyclothiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• methyl aminolevulinate

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

• metolazone

  Minor (1)metolazone increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• microbiota oral

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

• mineral oil

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

• nateglinide

  Monitor Closely (1)sulfisoxazole increases levels of nateglinide by plasma protein binding competition. Use Caution/Monitor.

• niacin

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

• nitisinone

  Monitor Closely (1)nitisinone will increase the level or effect of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Nitisinone inhibits CYP2C9. Caution if CYP2C9 substrate coadministered, particularly those with a narrow therapeutic index.

• paclitaxel

  Monitor Closely (1)sulfisoxazole will increase the level or effect of paclitaxel by Other (see comment). Modify Therapy/Monitor Closely. Paclitaxel levels/toxicity may increase when coadministered with CYP2C8 inhibitors

• paclitaxel protein bound

  Monitor Closely (1)sulfisoxazole will increase the level or effect of paclitaxel protein bound by Other (see comment). Modify Therapy/Monitor Closely. Paclitaxel levels/toxicity may increase when coadministered with CYP2C8 inhibitors

• pantothenic acid

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

• pexidartinib

  Serious - Use Alternative (1)sulfisoxazole and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.

• phenelzine

  Minor (1)phenelzine increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• phenindione

  Serious - Use Alternative (2)sulfisoxazole increases effects of phenindione by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of phenindione by plasma protein binding competition. Avoid or Use Alternate Drug.

• phenytoin

  Minor (1)sulfisoxazole increases levels of phenytoin by decreasing metabolism. Minor/Significance Unknown.

• pretomanid

  Serious - Use Alternative (1)sulfisoxazole, 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.

• primaquine

  Minor (1)primaquine, sulfisoxazole. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hemolysis in G6PD deficient pts.

• probenecid

  Minor (1)probenecid increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• promazine

  Monitor Closely (1)promazine increases toxicity of sulfisoxazole by unspecified interaction mechanism. Use Caution/Monitor. Enhanced myelosuppression.

• protamine

  Serious - Use Alternative (2)sulfisoxazole increases effects of protamine by decreasing metabolism. Avoid or Use Alternate Drug.
  
  sulfisoxazole increases effects of protamine by plasma protein binding competition. Avoid or Use Alternate Drug.

• pyridoxine

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

• pyridoxine (Antidote)

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

• pyrimethamine

  Minor (1)sulfisoxazole, pyrimethamine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased bone marrow toxicity.

• repaglinide

  Monitor Closely (1)sulfisoxazole increases levels of repaglinide by plasma protein binding competition. Use Caution/Monitor.

• rucaparib

  Monitor Closely (1)rucaparib will increase the level or effect of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP2C9 substrates, if clinically indicated.

• salicylates (non-asa)

  Minor (1)salicylates (non-asa) increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• salsalate

  Minor (1)salsalate increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• selegiline transdermal

  Minor (1)selegiline transdermal increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• sparsentan

  Monitor Closely (1)sparsentan will decrease the level or effect of sulfisoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Sparsentan (a CYP2C9 inducer) decreases exposure of CYP2C9 substrates and reduces efficacy related to these substrates.

• spironolactone

  Minor (1)spironolactone increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• sulfasalazine

  Minor (1)sulfasalazine increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• tetracaine

  Monitor Closely (1)tetracaine, sulfisoxazole. Other (see comment). Use Caution/Monitor. Comment: Monitor for signs of methemoglobinemia when methemoglobin-inducing drugs are coadministered.

• thiamine

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

• tolazamide

  Monitor Closely (1)sulfisoxazole increases levels of tolazamide by plasma protein binding competition. Use Caution/Monitor.

• tolbutamide

  Monitor Closely (1)sulfisoxazole increases levels of tolbutamide by plasma protein binding competition. Use Caution/Monitor.

• torsemide

  Minor (1)torsemide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• tranylcypromine

  Minor (1)tranylcypromine increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• tretinoin

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

• tretinoin topical

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

• triamterene

  Minor (1)triamterene increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• typhoid vaccine live

  Serious - Use Alternative (1)sulfisoxazole decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.

• valoctocogene roxaparvovec

  Monitor Closely (1)sulfisoxazole 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.

• verteporfin

  Minor (1)sulfisoxazole, verteporfin. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased phototoxicity.

• voclosporin

  Monitor Closely (1)voclosporin, sulfisoxazole. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.

• willow bark

  Minor (1)willow bark increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.