The relationship of sodium balance and concomitant diuretic therapy to blood pressure response with calcium channel entry blockers.

Marked heterogeneity exists in the response of blood pressure to specific antihypertensive agents. In general, a single therapeutic agent can be expected to provide an adequate blood pressure response in 40% to 60% of hypertensive patients. The addition of a second agent usually extends the response rate to over 85%. The addition of a diuretic to nondiuretic regimens often produces an additive blood pressure-lowering effect. However, calcium channel entry blockers (CCBs) may be an exception, as diuretics do not appear to improve these agents' efficacy. CCBs have a dual mechanism for blood pressure reduction. In addition to their vasodilatory actions, they also promote diuresis and natriuresis. These features account for the striking efficacy of these agents when used as monotherapy in hypertensive patients. Studies have shown that dietary sodium restriction does not appear to improve the efficacy of CCBs, nor is a high-salt diet predictive of a better therapeutic outcome. Recent studies also indicate that the addition of a diuretic to a CCB does not produce a significant or consistent additive antihypertensive effect. Because CCBs do not produce the typical responses of the renin-angiotensin-aldosterone (RAA) system to sodium/volume depletion, their diuretic and natriuretic effects do not result in the same adverse metabolic consequences as experienced with traditional diuretic therapy.