The effect of cimetidine co-administration on the renal elimination of sulfadiazine, has been investigated in eight healthy male volunteers. Single dose of 400 mg cimetidine coadministration, increases significantly the renal clearance of sulfadiazine from 12.01 plus/minus SEM 1.82 ml/minutes to 16.41 plus/minus SEM 1.93 ml/minutes (p less than 0.05). The increase in sulfadiazine clearance corr…