Ranitidine does not affect chlormethiazole or indocyanine green disposition.

Cimetidine has been shown to inhibit hepatic mixed-function oxidase activity and to lower hepatic blood flow. It is not known whether these effects are related to its H2-receptor antagonism or to its intrinsic structure. Ranitidine is a more potent H2-receptor antagonist and differs structurally from cimetidine. In our study, ranitidine, 150 mg twice daily, had no effect on oral or systemic clearance of chlormethiazole, a sedative with a high clearance, and no effect on indocyanine green elimination.