Answer 83 - Anti-tuberculous chemotherapy
Concerning anti-tuberculous chemotherapy:
True a. pyrazinamide causes hyperuricaemia
True b. isoniazid causes a lupus-like syndrome
False c. twice weekly regimens should be continued for at least 12 months
False d. pyridoxine is only needed by slow acetylators
False e. rifampicin can only be given orally
All anti-tuberculous drugs may cause anorexia, nausea and vomiting.
Pyrazinamide is bactericidal and penetrates the meninges well. Its side effects include fever, liver failure and hyperuricaemia.
Isoniazid is generally safe. The most common side effect is peripheral neuropathy. This is more common in diabetes and alcoholics. Pyridoxine should always be given to such patients. Slow acetylator status increases risk of neuropathy and of lupus-like syndrome. Other side effects include psychosis, fever and hepatitis.
Rifampicin can be given orally or intravenously. Transient elevation of transaminases is common. Six toxicity syndromes have been described: influenzal, abdominal, respiratory, shock, renal and thrombocytopaenic.
Compliance is a major problem in the developing world. Expense, cultural beliefs, the need to travel to get the drugs, drug side effects and variable drug supply all contribute towards poor compliance.
