AN INVESTIGATION AND COMPARISON OF TWO DRUG INTERACTIONS: CIMETIDINE - DOXEPIN RANITIDINE - DOXEPIN
The Hz-receptor antagonist, cimetidine, profoundly inhibits gastric acid secretion and is effectively and widely used in the management of peptic ulcer disease and other hypersecretory states of the gastrointestinal tract (Brogden et al., 1978). Ranitidine hydrochloride, a new 142-receptor antagonist has been developed in an attempt to improve upon the deficiencies observed with cimetidine. Ranitidine appears to have a greater potency, less systemic toxicity and fewer drug interactions than cimetidine (Berner et al., 1982). Recently, cimetidine has been shown to interfere with the metabolism of a number of drugs, including tricyclic antidepressants. Three isolated case reports, two involving cimetidine and imipramine (Miller and Macklin, 1983; Shapiro, 1984) and the other cimetidine and nortriptyline (Miller et aI., 1983) document elevated plasma levels of the tricyclic antidepressants with concurrent cimetidine therapy. In addition the same interactions between cimetidine and imipramine (Abernethy, 1983) or nortriptyline (Henauer and Hollister, 1984) have also been observed in two separate investigations each studying six healthy subjects. In these reports, pretreatment with cimetidine elevated the plasma levels and prolonged the half-lives of imipramine and nortriptyline.
Master of Science (M.Sc.)
Pharmacy and Nutrition