[Pyrazinamide versus ethambutol in short-term therapy of lung tuberculosis. A randomized study]

Recent experience suggests that the duration of chemotherapy of tuberculosis can be shortened to 6-9 months, without an increase in the relapse rate, if the treatment if started with 3 or 4 drugs including isoniazid (INH), rifampicin (RMP) and pyrazinamide (PZA). In a controlled study of culture-positive advanced pulmonary tuberculosis we have compared treatment regimens with PZA in a dosage of less than 2 g and with ethambutol (EMB). 113 patients were given, in random order for 2-3 months, either PZA (25 mg/kg body weight) or EMB (25 mg/kg) together with RMP (450 or 600 mg) and INH (5 mg/kg). The last two drugs were given for a total of 9 months. Patients treated with PZA showed a (not significantly) earlier conversion to negative cultures after an average of 7 weeks. After 18 months follow-up there have been no relapses on these regimens. 2 patients, both treated with EMB, did not respond to therapy. Drug-induced hepatitis was seen in 5 patients with PZA and in 2 patients with EMB. The hepatitis was always observed during the first month of therapy and was fully reversible. Three of the 4 patients with clinically apparent hepatitis were over 70 years of age. Three patients with elevated uric acid levels had arthralgia which led in one of them to termination of therapy. The preliminary results of our study show that the treatment regimen with PZA does not lead to a higher rate of side effects if used with particular moderation in older patients.