Home›Isoniazid

Isoniazid

Also known as: Isoniazid

Antimycobacterial

Route: Oral

78 interactions on record⛔ Black Box Warning

Isoniazid has 78 known drug interactions based on U.S. FDA drug labeling data. Of these, 1 are contraindicated combinations that should be avoided entirely. 8 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Bacillus Calmette-Guerin, Acetaminophen, Carbamazepine. Patients taking Isoniazid should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.

Total: 78
Contraindicated: 1
Major: 8
Moderate: 68

Contraindicated (1)

Isoniazid + Bacillus Calmette-Guerin— Antituberculosis drugs should not be used to prevent or treat local irritative toxicities of TICE BCG, as these are not …

Major (8)

Isoniazid + Acetaminophen— Isoniazid induces P-450IIE1 enzyme, increasing conversion of acetaminophen to toxic metabolites and potentiating hepatot…
Isoniazid + Carbamazepine— Isoniazid slows metabolism and increases serum levels of carbamazepine, requiring monitoring for toxicity signs and dosa…
Isoniazid + Insulin Glargine— May decrease blood glucose lowering effect of LANTUS. Dosage increases and increased glucose monitoring may be required.
Isoniazid + Itraconazole— Potent CYP3A4 enzyme inducer that may decrease itraconazole bioavailability and efficacy. Avoid use 2 weeks before and d…
Isoniazid + Ketoconazole— Ketoconazole AUC is decreased by up to 88% when combined with isoniazid and rifampin after 5 months of concurrent therap…
Isoniazid + Phenytoin— Isoniazid may increase serum levels of phenytoin, requiring dosage adjustment to avoid phenytoin intoxication.
Isoniazid + Rifampin— Concomitant use increases potential for hepatotoxicity. Patients should be monitored closely.
Isoniazid + Theophylline— Concurrent isoniazid and theophylline administration may cause elevated plasma theophylline levels. Close monitoring and…

Moderate (68)

Isoniazid + Acarbose— Isoniazid produces hyperglycemia and may lead to loss of blood glucose control in patients receiving Acarbose. Close obs…
Isoniazid + Acetaminophen, Caffeine, Dihydrocodeine Bitartrate— Increases potential for acetaminophen hepatotoxicity.
Isoniazid + Alogliptin And Metformin Hydrochloride— May produce hyperglycemia and lead to loss of glycemic control.
Isoniazid + Alprazolam— Possible drug interaction with alprazolam based on clinical studies in other benzodiazepines. Caution recommended during…
Isoniazid + Ascorbic Acid, Vitamin A Palmitate, Cholecalciferol, Thiamine Hydrochloride, Riboflavin-5 Phosphate Sodium, Pyridoxine Hydrochloride, Niacinamide, Dexpanthenol, Alpha-Tocopherol Acetate, Vitamin K1, Folic Acid, Biotin, Cyanocobalamin— Concomitant administration may increase pyridoxine requirements.
Isoniazid + Betamethasone Sodium Phosphate, Betamethasone Acetate, Lidocaine, Iodixanol, Povidine Iodine— Serum concentrations of isoniazid may be decreased by corticosteroids.
Isoniazid + Carbidopa— May reduce the therapeutic effects of levodopa; patients should be carefully observed for loss of therapeutic response.
Isoniazid + Carbidopa And Levodopa— May reduce the therapeutic effects of levodopa; patients should be carefully observed for loss of therapeutic response.
Isoniazid + Carbidopa Tablets— May reduce therapeutic effects of levodopa; patients should be carefully observed for loss of therapeutic response.
Isoniazid + Carbidopa, Levodopa And Entacapone— May reduce therapeutic effects of levodopa; dose increase may be necessary.
Isoniazid + Dapagliflozin And Metformin Hydrochloride— Produces hyperglycemia and may lead to loss of glycemic control when used with XIGDUO XR.
Isoniazid + Depo-Medrol, Lidocaine, Isopropyl Alcohol— Serum concentrations of isoniazid may be decreased by corticosteroids.
Isoniazid + Dexamethasone— Serum concentrations of isoniazid may be decreased by dexamethasone.
Isoniazid + Dexamethasone 1.5 Mg— Serum concentrations of isoniazid may be decreased when used with dexamethasone.
Isoniazid + Dexamethasone Intensol— Serum concentrations of isoniazid may be decreased by dexamethasone.
Isoniazid + Disulfiram— Patients should be observed for unsteady gait or marked changes in mental status. Disulfiram should be discontinued if s…
Isoniazid + Empagliflozin, Metformin Hydrochloride— May produce hyperglycemia and lead to loss of glycemic control; monitor closely.
Isoniazid + Ertugliflozin And Metformin Hydrochloride— May produce hyperglycemia and lead to loss of glycemic control; close monitoring recommended.
Isoniazid + Estazolam— Significant CYP3A inhibitor; estazolam should be used with caution and appropriate dosage reduction may be needed.
Isoniazid + Folic Acid— Isoniazid reduces folate utilization through metabolic disruption.
Isoniazid + Foscarbidopa/Foslevodopa— May reduce the effectiveness of foslevodopa. Monitor patients for worsening Parkinson's symptoms.
Isoniazid + Fosphenytoin Sodium— May increase phenytoin serum levels; monitoring of phenytoin levels recommended.
Isoniazid + Glibenclamide— Isoniazid may produce hyperglycemia and lead to loss of control of glyburide. Patients should be closely observed for lo…
Isoniazid + Glimepiride— May reduce glucose-lowering effect of glimepiride, leading to worsening glycemic control.
Isoniazid + Glipizide— Isoniazid may produce hyperglycemia and lead to loss of glycemic control. Patient should be observed closely for loss of…
Isoniazid + Glipizide And Metformin Hydrochloride— Isoniazid may produce hyperglycemia and lead to loss of blood glucose control. Patient should be closely observed for lo…
Isoniazid + Glyburide And Metformin Hydrochloride— Isoniazid tends to produce hyperglycemia and may lead to loss of blood glucose control. Close observation required.
Isoniazid + Hydrocortisone Acetate— Serum concentrations of isoniazid may be decreased by corticosteroids.
Isoniazid + Hydrocortisone Sodium Succinate— Serum concentrations of isoniazid may be decreased when used with corticosteroids.
Isoniazid + Insulin Aspart Injection— May decrease the blood glucose lowering effect. Dose adjustment and increased glucose monitoring required.
Isoniazid + Insulin Aspart-Szjj— May decrease blood glucose lowering effect. Dose adjustment and increased glucose monitoring may be required.
Isoniazid + Insulin Degludec— May decrease blood glucose lowering effect. Dosage increases and increased glucose monitoring may be required.
Isoniazid + Insulin Degludec And Liraglutide— May decrease blood glucose-lowering effect; dosage increases and increased glucose monitoring may be required.
Isoniazid + Insulin Detemir— May decrease blood glucose lowering effect of insulin detemir. Dosage increases and increased glucose monitoring may be …
Isoniazid + Insulin Glargine And Lixisenatide— May decrease the blood glucose lowering effect. Dose increases and increased glucose monitoring may be required.
Isoniazid + Insulin Glargine-Aglr— May decrease blood glucose lowering effect. Dosage increases and increased glucose monitoring may be required.
Isoniazid + Insulin Glargine-Yfgn— May decrease blood glucose lowering effect. Dosage increases and increased glucose monitoring may be required.
Isoniazid + Insulin Glulisine— May decrease blood glucose lowering effect. Dose adjustment and increased glucose monitoring may be required.
Isoniazid + Insulin Human— May decrease blood glucose lowering effect; dose adjustment and increased glucose monitoring may be required.
Isoniazid + Insulin Icodec-Abae— May decrease blood glucose lowering effect of Awiqli. Dose increases and increased glucose monitoring may be required.
Isoniazid + Insulin Lispro— May decrease blood glucose lowering effect; dose adjustment and increased glucose monitoring required.
Isoniazid + Insulin Lispro-Aabc— May decrease blood glucose lowering effect. Dose increases and increased glucose monitoring may be required.
Isoniazid + Kenalog— Serum concentrations of isoniazid may be decreased by corticosteroids.
Isoniazid + Levodopa— Isoniazid may reduce the effectiveness of levodopa. Monitor patients for worsening Parkinson's symptoms.
Isoniazid + Linagliptin And Metformin Hydrochloride— Isoniazid may produce hyperglycemia and lead to loss of glycemic control. Close monitoring of glycemic control is recomm…
Isoniazid + Marcaine, Lidocaine, Kenalog, Povidone Iodine— Serum concentrations of isoniazid may be decreased by corticosteroids.
Isoniazid + Metformin— Produces hyperglycemia and may lead to loss of glycemic control when used with metformin.
Isoniazid + Metformin Er 500 Mg— May produce hyperglycemia and lead to loss of glycemic control. Monitor patient closely for loss of blood glucose contro…
Isoniazid + Metformin Hydrochloride— Drugs that produce hyperglycemia and may lead to loss of glycemic control; monitor blood glucose.
Isoniazid + Metformin Hydrochloride Extended-Release Tablets— May produce hyperglycemia and lead to loss of glycemic control during metformin therapy; monitor blood glucose.
Isoniazid + Metformin Hydrochloride Tablet— May produce hyperglycemia and lead to loss of glycemic control when used with metformin.
Isoniazid + Methylprednisolone— Serum concentrations of isoniazid may be decreased when used with corticosteroids.
Isoniazid + Methylprednisolone Acetate— Serum concentrations of isoniazid may be decreased when used with corticosteroids.
Isoniazid + Methylprednisolone Acetate, Lidocaine Hydrochloride, Povidine Iodine, Isopropyl Alcohol— Serum concentrations of isoniazid may be decreased when used concomitantly with corticosteroids.
Isoniazid + Methylprednisolone Sodium Succinate— Serum concentrations of isoniazid may be decreased when used with corticosteroids.
Isoniazid + Multiple Vitamins Injection— Concomitant administration may increase pyridoxine requirements.
Isoniazid + Nimodipine— Moderate CYP3A4 inhibitor that may increase nimodipine plasma concentration and blood pressure lowering effect. Blood pr…
Isoniazid + Phenytoin Sodium— May increase phenytoin serum levels; monitoring of phenytoin levels recommended.
Isoniazid + Prednisolone Sodium Phosphate— Serum concentrations of isoniazid may be decreased by corticosteroid co-administration.
Isoniazid + Prednisone— Serum concentrations of isoniazid may be decreased by concurrent corticosteroid use.
Isoniazid + Propranolol Hydrochloride— CYP1A2 substrate/inhibitor that may increase blood levels and/or toxicity of propranolol.
Isoniazid + Repaglinide— May decrease blood glucose lowering effect of repaglinide. Dose increases and increased glucose monitoring may be requir…
Isoniazid + Safinamide Mesylate— Has monoamine oxidase inhibiting activity; monitor for hypertension and reaction to dietary tyramine.
Isoniazid + Sitagliptin And Metformin Hydrochloride— May produce hyperglycemia and lead to loss of glycemic control. Monitor blood glucose closely during concomitant use.
Isoniazid + Triamcinolone Acetonide— Serum concentrations of isoniazid may be decreased by corticosteroids.
Isoniazid + Triamcinolone Acetonide Extended-Release Injectable Suspension— Serum concentrations of isoniazid may be decreased with concurrent corticosteroid use.
Isoniazid + Triazolam— Coadministration increased maximum plasma concentration by 20%, decreased clearance by 42%, and increased half-life by 3…
Isoniazid + Valproate— Isoniazid may increase plasma levels of valproate. Plasma valproate concentration should be monitored and dosage adjustm…

Isoniazid + Bacillus Calmette-Guerin⛔Contraindicated

Antituberculosis drugs should not be used to prevent or treat local irritative toxicities of TICE BCG, as these are not due to mycobacterial infection.

Isoniazid + Acetaminophen⚠️Major

Isoniazid induces P-450IIE1 enzyme, increasing conversion of acetaminophen to toxic metabolites and potentiating hepatotoxicity. Severe acetaminophen toxicity has been reported.

Isoniazid + Carbamazepine⚠️Major

Isoniazid slows metabolism and increases serum levels of carbamazepine, requiring monitoring for toxicity signs and dosage adjustment.

Isoniazid + Insulin Glargine⚠️Major

May decrease blood glucose lowering effect of LANTUS. Dosage increases and increased glucose monitoring may be required.

Isoniazid + Itraconazole⚠️Major

Potent CYP3A4 enzyme inducer that may decrease itraconazole bioavailability and efficacy. Avoid use 2 weeks before and during itraconazole treatment.

Isoniazid + Ketoconazole⚠️Major

Ketoconazole AUC is decreased by up to 88% when combined with isoniazid and rifampin after 5 months of concurrent therapy.

Isoniazid + Phenytoin⚠️Major

Isoniazid may increase serum levels of phenytoin, requiring dosage adjustment to avoid phenytoin intoxication.

Isoniazid + Rifampin⚠️Major

Concomitant use increases potential for hepatotoxicity. Patients should be monitored closely.

Isoniazid + Theophylline⚠️Major

Concurrent isoniazid and theophylline administration may cause elevated plasma theophylline levels. Close monitoring and dosage adjustment recommended due to theophylline's narrow therapeutic range.

Isoniazid + Acarbose🟡Moderate

Isoniazid produces hyperglycemia and may lead to loss of blood glucose control in patients receiving Acarbose. Close observation for loss of glucose control is recommended.

Isoniazid + Acetaminophen, Caffeine, Dihydrocodeine Bitartrate🟡Moderate

Increases potential for acetaminophen hepatotoxicity.

Isoniazid + Alogliptin And Metformin Hydrochloride🟡Moderate

May produce hyperglycemia and lead to loss of glycemic control.

Isoniazid + Alprazolam🟡Moderate

Possible drug interaction with alprazolam based on clinical studies in other benzodiazepines. Caution recommended during coadministration.

Isoniazid + Ascorbic Acid, Vitamin A Palmitate, Cholecalciferol, Thiamine Hydrochloride, Riboflavin-5 Phosphate Sodium, Pyridoxine Hydrochloride, Niacinamide, Dexpanthenol, Alpha-Tocopherol Acetate, Vitamin K1, Folic Acid, Biotin, Cyanocobalamin🟡Moderate

Concomitant administration may increase pyridoxine requirements.

Isoniazid + Betamethasone Sodium Phosphate, Betamethasone Acetate, Lidocaine, Iodixanol, Povidine Iodine🟡Moderate

Serum concentrations of isoniazid may be decreased by corticosteroids.

Isoniazid + Carbidopa🟡Moderate

May reduce the therapeutic effects of levodopa; patients should be carefully observed for loss of therapeutic response.

Isoniazid + Carbidopa And Levodopa🟡Moderate

May reduce the therapeutic effects of levodopa; patients should be carefully observed for loss of therapeutic response.

Isoniazid + Carbidopa Tablets🟡Moderate

May reduce therapeutic effects of levodopa; patients should be carefully observed for loss of therapeutic response.

Isoniazid + Carbidopa, Levodopa And Entacapone🟡Moderate

May reduce therapeutic effects of levodopa; dose increase may be necessary.

Isoniazid + Dapagliflozin And Metformin Hydrochloride🟡Moderate

Produces hyperglycemia and may lead to loss of glycemic control when used with XIGDUO XR.

Isoniazid + Depo-Medrol, Lidocaine, Isopropyl Alcohol🟡Moderate

Serum concentrations of isoniazid may be decreased by corticosteroids.

Isoniazid + Dexamethasone🟡Moderate

Serum concentrations of isoniazid may be decreased by dexamethasone.

Isoniazid + Dexamethasone 1.5 Mg🟡Moderate

Serum concentrations of isoniazid may be decreased when used with dexamethasone.

Isoniazid + Dexamethasone Intensol🟡Moderate

Serum concentrations of isoniazid may be decreased by dexamethasone.

Isoniazid + Disulfiram🟡Moderate

Patients should be observed for unsteady gait or marked changes in mental status. Disulfiram should be discontinued if such signs appear.

Isoniazid + Empagliflozin, Metformin Hydrochloride🟡Moderate

May produce hyperglycemia and lead to loss of glycemic control; monitor closely.

Isoniazid + Ertugliflozin And Metformin Hydrochloride🟡Moderate

May produce hyperglycemia and lead to loss of glycemic control; close monitoring recommended.

Isoniazid + Estazolam🟡Moderate

Significant CYP3A inhibitor; estazolam should be used with caution and appropriate dosage reduction may be needed.

Isoniazid + Folic Acid🟡Moderate

Isoniazid reduces folate utilization through metabolic disruption.

Isoniazid + Foscarbidopa/Foslevodopa🟡Moderate

May reduce the effectiveness of foslevodopa. Monitor patients for worsening Parkinson's symptoms.

Isoniazid + Fosphenytoin Sodium🟡Moderate

May increase phenytoin serum levels; monitoring of phenytoin levels recommended.

Isoniazid + Glibenclamide🟡Moderate

Isoniazid may produce hyperglycemia and lead to loss of control of glyburide. Patients should be closely observed for loss of control.

Isoniazid + Glimepiride🟡Moderate

May reduce glucose-lowering effect of glimepiride, leading to worsening glycemic control.

Isoniazid + Glipizide🟡Moderate

Isoniazid may produce hyperglycemia and lead to loss of glycemic control. Patient should be observed closely for loss of control when initiated or withdrawn.

Isoniazid + Glipizide And Metformin Hydrochloride🟡Moderate

Isoniazid may produce hyperglycemia and lead to loss of blood glucose control. Patient should be closely observed for loss of blood glucose control.

Isoniazid + Glyburide And Metformin Hydrochloride🟡Moderate

Isoniazid tends to produce hyperglycemia and may lead to loss of blood glucose control. Close observation required.

Isoniazid + Hydrocortisone Acetate🟡Moderate

Serum concentrations of isoniazid may be decreased by corticosteroids.

Isoniazid + Hydrocortisone Sodium Succinate🟡Moderate

Serum concentrations of isoniazid may be decreased when used with corticosteroids.

Isoniazid + Insulin Aspart Injection🟡Moderate

May decrease the blood glucose lowering effect. Dose adjustment and increased glucose monitoring required.

Isoniazid + Insulin Aspart-Szjj🟡Moderate

May decrease blood glucose lowering effect. Dose adjustment and increased glucose monitoring may be required.

Isoniazid + Insulin Degludec🟡Moderate

May decrease blood glucose lowering effect. Dosage increases and increased glucose monitoring may be required.

Isoniazid + Insulin Degludec And Liraglutide🟡Moderate

May decrease blood glucose-lowering effect; dosage increases and increased glucose monitoring may be required.

Isoniazid + Insulin Detemir🟡Moderate

May decrease blood glucose lowering effect of insulin detemir. Dosage increases and increased glucose monitoring may be required.

Isoniazid + Insulin Glargine And Lixisenatide🟡Moderate

May decrease the blood glucose lowering effect. Dose increases and increased glucose monitoring may be required.

Isoniazid + Insulin Glargine-Aglr🟡Moderate

May decrease blood glucose lowering effect. Dosage increases and increased glucose monitoring may be required.

Isoniazid + Insulin Glargine-Yfgn🟡Moderate

May decrease blood glucose lowering effect. Dosage increases and increased glucose monitoring may be required.

Isoniazid + Insulin Glulisine🟡Moderate

May decrease blood glucose lowering effect. Dose adjustment and increased glucose monitoring may be required.

Isoniazid + Insulin Human🟡Moderate

May decrease blood glucose lowering effect; dose adjustment and increased glucose monitoring may be required.

Isoniazid + Insulin Icodec-Abae🟡Moderate

May decrease blood glucose lowering effect of Awiqli. Dose increases and increased glucose monitoring may be required.

Isoniazid + Insulin Lispro🟡Moderate

May decrease blood glucose lowering effect; dose adjustment and increased glucose monitoring required.

Isoniazid + Insulin Lispro-Aabc🟡Moderate

May decrease blood glucose lowering effect. Dose increases and increased glucose monitoring may be required.

Isoniazid + Kenalog🟡Moderate

Serum concentrations of isoniazid may be decreased by corticosteroids.

Isoniazid + Levodopa🟡Moderate

Isoniazid may reduce the effectiveness of levodopa. Monitor patients for worsening Parkinson's symptoms.

Isoniazid + Linagliptin And Metformin Hydrochloride🟡Moderate

Isoniazid may produce hyperglycemia and lead to loss of glycemic control. Close monitoring of glycemic control is recommended.

Isoniazid + Marcaine, Lidocaine, Kenalog, Povidone Iodine🟡Moderate

Serum concentrations of isoniazid may be decreased by corticosteroids.

Isoniazid + Metformin🟡Moderate

Produces hyperglycemia and may lead to loss of glycemic control when used with metformin.

Isoniazid + Metformin Er 500 Mg🟡Moderate

May produce hyperglycemia and lead to loss of glycemic control. Monitor patient closely for loss of blood glucose control.

Isoniazid + Metformin Hydrochloride🟡Moderate

Drugs that produce hyperglycemia and may lead to loss of glycemic control; monitor blood glucose.

Isoniazid + Metformin Hydrochloride Extended-Release Tablets🟡Moderate

May produce hyperglycemia and lead to loss of glycemic control during metformin therapy; monitor blood glucose.

Isoniazid + Metformin Hydrochloride Tablet🟡Moderate

May produce hyperglycemia and lead to loss of glycemic control when used with metformin.

Isoniazid + Methylprednisolone🟡Moderate

Serum concentrations of isoniazid may be decreased when used with corticosteroids.

Isoniazid + Methylprednisolone Acetate🟡Moderate

Serum concentrations of isoniazid may be decreased when used with corticosteroids.

Isoniazid + Methylprednisolone Acetate, Lidocaine Hydrochloride, Povidine Iodine, Isopropyl Alcohol🟡Moderate

Serum concentrations of isoniazid may be decreased when used concomitantly with corticosteroids.

Isoniazid + Methylprednisolone Sodium Succinate🟡Moderate

Serum concentrations of isoniazid may be decreased when used with corticosteroids.

Isoniazid + Multiple Vitamins Injection🟡Moderate

Concomitant administration may increase pyridoxine requirements.

Isoniazid + Nimodipine🟡Moderate

Moderate CYP3A4 inhibitor that may increase nimodipine plasma concentration and blood pressure lowering effect. Blood pressure monitoring and dose reduction of nimodipine may be necessary.

Isoniazid + Phenytoin Sodium🟡Moderate

May increase phenytoin serum levels; monitoring of phenytoin levels recommended.

Isoniazid + Prednisolone Sodium Phosphate🟡Moderate

Serum concentrations of isoniazid may be decreased by corticosteroid co-administration.

Isoniazid + Prednisone🟡Moderate

Serum concentrations of isoniazid may be decreased by concurrent corticosteroid use.

Isoniazid + Propranolol Hydrochloride🟡Moderate

CYP1A2 substrate/inhibitor that may increase blood levels and/or toxicity of propranolol.

Isoniazid + Repaglinide🟡Moderate

May decrease blood glucose lowering effect of repaglinide. Dose increases and increased glucose monitoring may be required.

Isoniazid + Safinamide Mesylate🟡Moderate

Has monoamine oxidase inhibiting activity; monitor for hypertension and reaction to dietary tyramine.

Isoniazid + Sitagliptin And Metformin Hydrochloride🟡Moderate

May produce hyperglycemia and lead to loss of glycemic control. Monitor blood glucose closely during concomitant use.

Isoniazid + Triamcinolone Acetonide🟡Moderate

Serum concentrations of isoniazid may be decreased by corticosteroids.

Isoniazid + Triamcinolone Acetonide Extended-Release Injectable Suspension🟡Moderate

Serum concentrations of isoniazid may be decreased with concurrent corticosteroid use.

Isoniazid + Triazolam🟡Moderate

Coadministration increased maximum plasma concentration by 20%, decreased clearance by 42%, and increased half-life by 31%.

Isoniazid + Valproate🟡Moderate

Isoniazid may increase plasma levels of valproate. Plasma valproate concentration should be monitored and dosage adjustments made as needed.

Isoniazid + Desogestrel And Ethinyl Estradiol And Ethinyl Estradiolℹ️Unknown

Isoniazid is a CYP2C9 substrate that may interact with desogestrel metabolism. Clinical relevance of this interaction is unknown.

Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine, supplemented with a small number of well-established interactions from curated clinical references. For informational purposes only. Always consult your pharmacist or physician.