In a controlled trial in Hong Kong, 575 Chinese patients with pulmonary tuberculosis whose treatment with first-line regimens had failed were allocated at random to the following retreatment regimens of chemotherapy.
(1) Rifampicin plus ethambutol daily (ER7).
(2) Rifampicin plus ethambutol twice a week (ER2).
(3) Rifampicin plus ethambutol once a week (ER1).
(4) Rifampicin plus ethambutol daily for 2 months and then once a week (ER7ER1).
(5) Ethionamide plus pyrazinamide plus cycloserine daily for 6 months and then ethionamide plus pyrazinamide daily (EtZC), as a control regimen.
Answers to a questionnaire on allergic disease, the results of prick tests with standard allergens, ABO blood grouping, size of tuberculin response during chemotherapy, and a rifampicin patch test showed no associations with the occurrence of adverse reactions to daily or intermittent rifampicin.
Mantoux testing during chemotherapy provided no evidence of an immuno-suppressive effect of rifampicin.
Mean platelet counts at 12 months were significantly lower than those at 3 months on the two once-weekly regimens (ER1, ER7ER1) and on the control regimen (EtZC), although still within normal limits. At 3 months, but not at 12 months, mean platelet counts on the two once-weekly regimens were significantly lower 6 hr after a dose of the regimen than they were before the dose.