Histamine H2-receptor antagonists and high-density lipoproteins.

Epidemiologic evidence has shown that elevated levels of high-density lipoproteins (HDL) protect against the development of coronary heart disease (CHD). These observations have prompted the evaluation of various factors thought to affect HDL and its subspecies, HDL2 and HDL3. Numerous behavioral and physiologic factors have been shown to elevate HDL levels. These are currently being researched as potential tools in preventing CHD. Several pharmacologic agents are known to alter HDL levels. Studies show that patients with peptic ulcer disease treated with the H2-receptor antagonist cimetidine show significant elevations in their HDL, HDL2, and HDL3 profiles. In contrast, ranitidine has no effect, or may even decrease HDL levels. These divergent effects may be related to differences in pharmacologic activity unrelated to H2-receptor blockade. It should be noted that many of the variables affecting HDL levels were not controlled in these studies, and definite conclusions should not be extrapolated to the general population at risk for CHD. Currently, well-controlled trials to study the effect of cimetidine on HDL levels are in progress.