Review of salt restriction and the response to antihypertensive drugs. Satellite symposium on calcium antagonists.

We evaluated the response to salt restriction in hypertensive patients receiving drugs. By restricting their salt intake to less than 80 mmol of sodium per day for 3 months, 50% of patients reaching goal compliance were able to discontinue diuretics. The literature also reveals responses to a low salt diet. Salt restriction augmented the hypotensive effect of chlorthalidone in two investigations, but not in another, and the hypotensive effect of beta-blockers in three trials. Sodium intake of 10 mmol/day caused a much greater decrease in blood pressure in response to a single dose of captopril than did a sodium diet of 200 mmol/day. In patients receiving various fixed regimens for 2 months, salt restriction decreased blood pressure in all but those receiving calcium blockers. A single dose of nifedipine lowered blood pressure more in patients receiving 350 mmol of sodium per day than in the same patients given 150 or 10 mmol/day. Verapamil for 3 days was more effective in patients receiving 212 mmol of sodium per day than in the same subjects receiving 9 mmol/day. Nitrendipine caused a greater decrease in diastolic blood pressure in patients who did not reduce salt intake compared to those who did. Salt restriction appears useful in salt-sensitive patients who receive beta-blockers, diuretics, converting enzyme inhibitors, or centrally acting drugs. Calcium channel entry blockers may not require salt restriction to maximize their effect.