Aim: To compare the efficacy of indapamide (1.25 mg daily) and low-salt diet (<100 mmol/day) separately and in combination in essential hypertensive patients with inadequate BP response to perindopril.
Design and methods: Randomized double-blind, double-dummy, crossover design. The randomized treatments were indapamide 1.25 mg daily, sodium chloride 80 mmol daily, the combination of indapamide and sodium chloride and placebo. All patients received perindopril 4 mg daily and maintained a low-sodium diet.
Results: 19 patients entered and 17 completed the study. Prior to randomization, average clinic sitting blood pressure was 162/101 mm Hg and average 24-h urine sodium excretion was 157 mmol/day. Compared to the phase in which patients received perindopril with sodium repletion, clinic and ambulatory BPs were significantly reduced (p<0.01) in all the other phases. Indapamide had a greater effect on BP than dietary sodium restriction, and in combination their effects were additive. The effect of indapamide on ambulatory BP persisted throughout 24 h, but the effect of the low-salt diet was predominantly observed during waking hours.
Conclusions: In hypertensives with BP resistant to the angiotensin converting enzyme (ACE) inhibitor perindopril, the diuretic indapamide had greater additional efficacy and longer duration of action than dietary sodium restriction. In combination they had additive effects on BP.