Contraindications
Hypersensitivity. Patient w/ jaundice. Concomitant use w/ saquinavir/ritonavir combination.
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Special Precautions
History of DM, psychosis, peripheral neuropathy. Patient w/ HIV infection, porphyria, malnutrition, slow acetylator status, epilepsy and alcohol dependence. Hepatic and severe renal impairment. Elderly. Pregnancy and lactation. Patient Counselling May impair ability to drive or operate machinery. May produce a reddish colouration of the urine, sweat, sputum, and tears. May permanently stain soft contact lenses. Patient should change from oral contraceptives to non-hormonal methods of birth control. Monitoring Parameters Monitor hepatic enzymes and function; bilirubin, serum creatinine, CBC and platelet count.
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Adverse Reactions
GI symptoms (e.g. anorexia, nausea, vomiting, constipation, diarrhoea), alterations in liver function, peripheral neuritis, optic neuritis, headache, drowsiness, convulsions, vertigo, blood disorders (e.g. leucopenia, haemolytic anaemia, aplastic anaemia, eosinophilia), dry mouth, itching w/ or w/o rash, flushing, urticaria, rash, purpura, pancreatitis, oedema, interstitial pneumonitis, hyperreflexia, hyperglycaemia, adrenal insufficiency, gynaecomastia, menstrual disturbances, difficulty in micturition, muscular weakness, myopathy, SLE-like syndrome, pellagra, exfoliative dermatitis, pemphigus, toxic epidermal necrolysis, pemphigoid reactions, orange-red discolouration of urine, saliva and other body secretions; hearing loss and tinnitus, influenza-like symptoms, resp symptoms, collapse and shock, thrombocytopenic purpura, disseminated intravascular coagulation, acute renal failure. Rarely, psychoses, pemphigoid reaction, erythema multiforme, Lyells syndrome and vasculitis.
Potentially Fatal: Severe/fatal hepatitis (e.g. jaundice). |
Drug Interactions
May reduce effectivity of hormonal contraceptives. Reduced absorption w/ antacids. May decrease plasma concentrations of antivirals (e.g. atazanavir, darunavir, fosamprenavir), atovaquone w/ rifampicin. Rifampicin may reduce serum levels of anticonvulsants (e.g. phenytoin), antiarrhythmics (e.g. disopyramide), oral anticoagulants, antifungals (e.g. ketoconazole), barbiturates, β-blockers, Ca channel blockers (e.g. diltiazem), chloramphenicol, clarithromycin, corticosteroids, ciclosporin, cardiac glycosides, clofibrate, dapsone, diazepam, doxycycline, fluoroquinolones (e.g. ciprofloxacin), haloperidol, oral hypoglycemic agents (sulfonylureas), levothyroxine, methadone, narcotic analgesics, progestins, quinine, tacrolimus, theophylline, TCAs (e.g. amitriptyline, nortriptyline) and zidovudine. Increased risk of hepatotoxicity w/ halothane. Isoniazid may inhibit the metabolism of anticonvulsants (e.g. carbamazepine, phenytoin), benzodiazepines (e.g. diazepam), haloperidol, ketoconazole, theophylline, and warfarin. May enhance the CNS effects of meperidine, cycloserine, and disulfiram w/ isoniazid. Loss of glucose control in patients on oral hypoglycaemics w/ isoniazid.
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CIMS Class
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ATC Classification
J04AC01 - isoniazid ; Belongs to the class of hydrazides. Used in the systemic treatment of tuberculosis.
J04AB02 - rifampicin ; Belongs to the class of antibiotics. Used in the systemic treatment of tuberculosis. |