REDUCTION OF SALT INTAKE DURING CONVERTING-ENZYME-INHIBITOR TREATMENTCOMPARED WITH ADDITION OF A THIAZIDE

A moderate reduction in salt intake lowers blood pressure in individua ls with hypertension and improves blood pressure control in those taki ng a converting enzyme inhibitor. However: it is unclear how effective reduction of salt intake is compared with addition of other drugs, in particular, thiazide diuretics. We directly compared the separate eff ects on blood pressure of reducing sodium intake or adding a thiazide diuretic in the presence of a converting enzyme inhibitor in a double- blind? randomized, crossover study. We studied 11 subjects with essent ial hypertension who had been taking 25 mg captopril twice daily for a t least 1 month. In the double-blind study, after 1 month of captopril alone: supine blood pressure was 151+/-5/95+/-4 (SEM) mm Hg. With the addition of 25 mg hydrochlorothiazide once daily for 1 month, blood p ressure fell to 137+/-5/87+/-3 mm Hg. When a moderate reduction in sal t intake (from 206+/-26 to 109+/-20 mmol urinary sodium/24 h) was adde d to captopril for 1 month, blood pressure was reduced by a similar am ount (to 137+/-4/90+/-3 mm Hg). Plasma potassium fell during the diure tic treatment (3.9+/-0.1 to 3.7+/-0.1 mmol/L, P<.05) but increased non significantly during salt reduction (3.9+/-0.1 to 4.1+/-0.2 mmol/L). T hese results clearly demonstrate that moderate salt reduction, which c an be easily achieved, is as effective as a thiazide diuretic in lower ing blood pressure in the presence of a converting enzyme inhibitor an d has the particular advantage that plasma potassium does not decrease , We recommend that all patients on a converting enzyme inhibitor be a dvised to reduce their dietary salt intake. This would lead to improve d blood pressure control and avoids the need for thiazide treatment in many patients.