Cimetidine's effect on steady-state serum nortriptyline concentrations.

A cimetidine-nortriptyline interaction in a 52-year-old black male is reported. After concomitant administration of cimetidine and nortriptyline for two weeks, steady-state nortriptyline concentrations fell 42 percent when cimetidine was discontinued. Later, during rechallenge with cimetidine, serum nortriptyline concentrations increased significantly, but subsequently fell again when cimetidine was discontinued. The possible clinical consequences of this interaction are discussed.