POTENTIATES THE EFFECT OF WARFARIN, PHENYTOIN, DIGOXIN, PROCAINAMIDE. IT REDUCES RENAL EXCRETION OF ZIDOVUDINE, LAMIVUDINE. DAPSONE AND TRIMETHOPRIM INCREASES EACH OTHERS SERUM CONCENTRATION WHEREAS RIFAMPICIN REDUCES ITS CONCENTRATION INCREASED RISK OF RENAL TOXICITY WITH CYCLOSPORIN.