Ethnics differences in the reactions to drugs and xenobiotics. Antihypertensive agents

Ethnic differences in responsiveness to certain antihypertensive agents have been demonstrated between blacks and whites. Whites exhibit a greater average fall in blood pressure following beta adrenergic blocking drugs and converting enzyme inhibitors than do blacks. On the other hand, the blood pressure of blacks is more responsive to diuretics. While the causes for these ethnic differences are unknown several explanations have been offered. The plasma renin activity of whites tends to be higher than that of blacks. More whites have high or normal plasma renin activity as opposed to blacks who have mostly low renin hypertension. ACE inhibitors and beta blockers may be more effective in whites because these drugs reduce the activity of the renin-angiotensin system. Blacks, on the other hand, are more responsive to diuretics possibly because they have more of a volume dependent hypertension and tend to retain sodium longer than whites.