Investigations of allergic status and blood counts in Chinese patients receiving daily or intermittent rifampicin in Hong Kong.

In a controlled trial in Hong Bong, 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 immunosuppressive 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.