Acetylation of dapsone (DDS) and sulfamethazine (SMZ), and plasma clearance of DDS were studied in Malaysian Chinese with lepromatous leprosy including 40 DDS-resistant and 44 non-resistant patients. Neither a patient's acetylation characteristics (DDS or SMZ), nor his plasma clearance rate, appeared to have predisposed him to the development of DDS resistance. A potentially important drug interaction between rifampin and DDS was discovered. After ingestion of rifampin for a minimum of 2 weeks, the plasma clearance of DDS was increased and the relative amount of the acetylated DDS was decreased. The implications of these results for the treatment of lepromatous leprosy are discussed.
Dr. Gelber was supported by the University of California International Center for Medical Research (UC ICMR) through research grant AI 10051 to the Department of International Health, School of Medicine, University of California, San Francisco from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, U. S. Public Health Service. Dr. Gelber also acknowledges the support of the Institute for Medical Research, Malaysia. The Leprosy Research Unit, Sungei Buloh, Malaysia, is jointly administered by the (British) Medical Research Council and the Malaysian Ministry of Health.