Formulary Monographs [ISONIAZID, 081604]
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ISONIAZID
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ANTITUBERCULOSIS AGENTS
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Tuberculosis, in combination with other drugs
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Peripheral neuritis (treat with 50-100mg pyridoxine daily). Hepatitis (like viral hepatitis) convulsions, optic neuritis with atrophy . Monitor SGOT, SGPT, (if symptomatic) Albumin phosphatase. Avoid concurrent use with antacids, wait at least one hour. Foods such as cheese or tuna may cause headache, pounding heartbeat, dizziness, sweating, chills or diarrhoea. If you have these symptoms call your doctor.c.f. prescribing in liver and renal disease p. 14, 31.
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Adult: 300mg (5mg/kg/day ) daily in a single dose. May also be given as 900mg (15mg/kg) twice weekly as a single dose. Pediatric:
10mg/kg daily. Take on empty stomach. May be taken with food to avoid upset stomach. |
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Category: C Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
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Distributed into milk but safe for nursing infants
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The treatment of tuberclosis can be divided into two phases, an initial phase where three drugs are used and a second or continious phase, where two drugs are used. The recommended regime is an initial phase of Isonaizid , Rifampicin and other Streptomycin or Ethambutol for two omnths and the continuation phase of Isonaizid and Rifampicin for seven months, i.e. a total treatent time of nine months. Isoniazid is still con-sidered to be the primary drug for chemotherapy of tuber-culosis.
Cautions/Side Effects Patients on long term Isoniazid should be given Pyridoxine Hydrochloride prophylactically. Rifampicin is a potent inducer of liver enzymes and may provide important interactions with other drugs. (see p. 42). |