Isoniazid interactions

Isoniazid Isoniazid is incompatible with sugars. Isoniazid overdose may be severe to fatal, and treatment is symptomatic and supportive, including stomach wash for control of convulsions and treating metabolic acidosis. Administration of pyridoxine and hemodialysis may be needed. Isoniazid interacts with carba-mazepine, phenytoin, diazepam, triazolam, chlorzoxazone, theophylline, ethosux-imide, enflurane, cycloserine, and warfarin. 

The absorption of antitubercular drugs may be reduced in patients with AIDS and an increase in rifampicin levels may be due to increased absorption in the presence of fluconazole. In contrast, it is suggested that ketoconazole impairs the absorption of rifampicin from the gut. Just how isoniazid interacts is uncertain. 

Witmer DR, Ritschel WA Phenytoin-isoniazid interaction a kinetic a proach to management DrugInteU Clin Pham (1984) 18,483-6. 

Carrion C, E inosa E, Herrero A, Garda B. Possible vincristine-isoniazid interaction. Am Pharmacodier (1995) 29, 201. 

Phenytoin interacts widi many different drugp. For example isoniazid, chloramphenicol, sulfonamides, benzodiazepines, succinimides, and cimetidine all increase phenytoin blood levels. The barbiturates, rifampin, theophylline, and warfarin decrease phenytoin blood levels. When administering the hydantoins with meperidine, die analgesic effect of meperidine is decreased. 

Antacids also have clinically significant drug interactions with tetracycline, ferrous sulfate, isoniazid, quinidine, sul-fonylureas, and quinolone antibiotics. Antacid-drug interactions are influenced by antacid composition, dose, dosage schedule, and formulation. 

Drugs that may interact with disulfiram include alcohol, benzodiazepines, caffeine, chlorzoxazone, cocaine, hydantoins, isoniazid, metronidazole, theophylline, tricyclic antidepressants, and warfarin. 

Drugs that may interact with isoniazid include acetaminophen, carbamazepine, chlorzoxazone, disulfiram, enflurane, hydantoins, ketoconazole, rifampin, and theophylline. 

Drugs that may interact with cycloserine include alcohol, ethionamide, and isoniazid. 

Drugs that may interact with zalcitabine include antacids, chloramphenicol, cisplatin, dapsone, didanosine, disulfiram, ethionamide, glutethimide, gold, hydralazine, iodoquinol, isoniazid, metronidazole, nitrofurantoin, phenytoin, ribavirin, vincristine, cimetidine, metoclopramide, amphotericin, aminoglycosides, foscarnet, antiretroviral nucleoside analogs, pentamidine, and probenecid. 

Pyridoxine [Vitamin B ] [Vitamin B Supplement] U e Rx prevention of vit B6 deficiency Action Vit supl Dose Adults. Deficiency 10-20 mg/d PO Drug-induced neuritis 100-200 mg/d 25-100 mg/d prophylaxis Peds. 5-25 mg/d x 3 wk Caution [A (C if doses exceed RDA), +] Contra Component aUCTgy Disp Tabs 25, 50, 100 mg inj 100 mg/mL SE Allergic Rxns, HA, N Interactions -1- Effects OF levodopa, phenobarbital, phenytoin EMS Can be used as an antidote for isoniazid poisoning OD May cause sensory nerve damage (numbness, tingling, reduced sensation) and coordination problems Sxs are usually revised aft stopping pyridoxine symptomatic and supportive... 

Isoniazid inhibits cytochrome P450 enzyme function and thus can interact with drugs that are subject to cytochrome P450 mediated metabolism like warfarin and the antiepileptic agents phenytoin and car-bamazepine. 

Isoniazid (child 10 mg/kg up to) 300 mg orally, for 6 months 15 mg/kg orally, for 6 months 15 mg/kg orally, for 6 months Hepatic enzyme elevation Hepatitis Peripheral neuropathy CNS (mild) Drug interactions Hepatitis risk increases with age and alcohol consumption. Pyridoxine can prevent peripheral neuropathy... 

Plasma phenytoin concentrations are increased in the presence of chloramphenicol, disulfiram, and isoniazid, since the latter drugs inhibit the hepatic metabolism of phenytoin. A reduction in phenytoin dose can alleviate the consequences of these drug-drug interactions. 

Drug interactions InsuUn requirements may be increased by medications with hyperglycemic activity such as corticosteroids, isoniazid, certain lipid-lowering drugs (e.g., niacin), estrogens, oral contraceptives, phenothiazines, and thyroid... 

Wright JM, Stokes EF, Sweeney VP. Isoniazid-induced carbamazepine toxicity and vice versa a double drug interaction. N EnglJ Med 1982 307 1325-1327. 

Drug interactions NSAIDs Salicylates Sulfonamides Chloramphenicol Probenecid Coumarins MAO inhibitors Beta-blockers Thiazides and other diuretics Corticosteroids Phenothiazines Thyroid products Estrogens Oral contraceptives Phenytoin Nicotinic acid Sympathomimetic Calcium channel blockers Isoniazid Miconazole... 

A clinically important example of microsomal enzyme inhibition is the interaction between the drugs isoniazid and diphenylhy dan loin. Termination of the pharmacological activity of diphenylhydantoin depends on microsomal metabolism (figure 7.54). This may be inhibited... 

The role of acetylhydrazine in isoniazid hepatotoxicity is complex, as the production of the toxic intermediate involves several steps. Further study has indicated that acetylhydrazine is detoxified by further acetylation to diacetlhydrazine (Fig. 7.24) and that isoniazid may interact with acetylhydrazine metabolism. It is therefore clear that the relative rates of production, detoxication, and activation of acetylhydrazine are very important determinants of the hepatotoxicity of isoniazid. 

Thus, the hepatotoxicity of iproniazid and isoniazid may involve the alkylation or acylation of tissue proteins and other macromolecules in the liver. How these covalent interactions lead to the observed hepatocellular necrosis is at present not understood. 

Another cause of toxicity with diphenylhydantoin can be the result of interactions with other drugs such as isoniazid. This drug is a noncompetitive inhibitor of the aromatic hydroxylation of diphenylhydantoin. Consequently, the elimination of diphenylhydantoin is impaired in the presence of isoniazid, and the plasma level is greater than anticipated for a normal therapeutic dose. Furthermore, it was found that there was a significant correlation... 

In other words, it takes about the same length of time to kill an animal with sleep deprivation as it does to cure a person with those drugs that restore sleep to normal for the duration of their administration. Some of those alterations are variations on the theme of sleep deprivation. The total suppression of REM by isoniazid and other MAOIs is a particularly striking example. Successful treatment of depression may thus depend upon pushing the two sides of the reciprocal interaction system to such extreme limits that REM sleep is impossible. 

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