Effect of clofazimine and dapsone on rifampicin (Lositril) pharmacokinetics in multibacillary and paucibacillary leprosy cases

Abstract

Clofazimine reduced rifampicin absortion significantly resulting in delayed time to reach peak serum concentration and increased t 1/2 , but no significant change was seen in area under curve, and maximum concentration because the elimination rate constant was reduced significantly by clofazimine when used withoug dapsone in addition to insignificant increase in metabolic clearance rate. In view of this, the following questions were raised: (a) Whether it is appropriate to give clofazimine daily when it is known to have a long half life. (b) Whether it would be rational to combine the monthly supervised dose of clofazimine (300 mg) with rifampicin (600 mg) in the light of the present findings. In view of this, whether it would be appropriate to increase the monthly dose of rifampicin to compensate for the 'clofazimine effect'.