Nifedipine and hypertension: roles of vasodilation and sodium balance.

Nifedipine reduces blood pressure predominantly by reducing systemic vascular resistance due to a direct vasodilating action on the arterioles. This peripheral vasodilation appears greater the more severe the hypertension. Nifedipine also causes a long-term loss of sodium, which may be an additive mechanism for the blood pressure fall. In patients who are not controlled on nifedipine alone, studies have demonstrated an additive effect of beta blockers and converting-enzyme inhibitors on blood pressure. There is controversy about whether diuretics have an additive effect on blood pressure in patients already on nifedipine.