Influence of once-monthly rifampicin and daily clofazimine on the pharmacokinetics of dapsone in leprosy patients in Nigeria.

In leprosy patients in Nigeria the influence of daily clofazimine and of once-monthly rifampicin on the pharmacokinetics of dapsone has been investigated. Three days after rifampicin the elimination half-life of dapsone was reduced from 40.4 to 25.3 h (n = 23). Correspondingly, the plasma dapsone 24 h after the last dose had fallen significantly from 2.63 to 2.02 mg/l. Clofazimine did not cause change in the pharmacokinetics of dapsone. It was concluded that, although rifampicin had a considerable influence on the pharmacokinetics of dapsone, there is no reason to adjust the dose of dapsone during multidrug therapy of leprosy.