The antihypertensive effect of verapamil at extremes of dietary sodium intake.

Restricting sodium intake is a primary recommendation for patients with hypertension, including those receiving drug treatment. Few studies, however, have examined the impact of different levels of sodium intake on the effectiveness of antihypertensive drugs. We administered two courses of verapamil to 13 patients with essential hypertension during a low-sodium (NaCl, 9 meq/d) and high-sodium (212 meq/d) diet. Overall, verapamil was an effective antihypertensive agent, but expressed its greatest potency in the lower-renin, sodium-sensitive subgroup. Moreover, the antihypertensive efficacy of verapamil was not blunted by the high-sodium intake (change in systolic/diastolic blood pressure, 18.8/17.7 in sodium sensitive patients compared with -11.4/-8.7 in sodium insensitive patients; p less than 0.05). Thus, dietary sodium restriction may not be necessary or appropriate in the treatment of essential hypertension with verapamil; salt-induced cellular calcium uptake may be involved in the phenomenon of sodium sensitivity.