Amiloride compared with nitrendipine in treatment of essential hypertension.

The antihypertensive effect of amiloride was compared to that of the calcium antagonist nitrendipine in 12 patients (8 males), aged 34-62 years, with essential hypertension WHO grade I-II (mean supine blood pressure 158/103, standing 155/106 mmHg) in a double-blind placebo-controlled cross-over study design. Amiloride was given 5 mg once daily for one month followed by 20 mg twice daily for another month. Amiloride 5 mg once daily significantly reduced supine and standing DBP but not SBP (supine 151/94, standing 149/97 mmHg), whereas 10 mg once daily decreased SBP as well as DBP (supine 145/98, standing 145/101 mmHg). Nitrendipine 20 mg once daily significantly reduced supine and standing SBP and standing DBP (supine 150/97, standing 148/98 mmHg), but on 20 mg twice daily only supine SBP was significantly reduced (supine 150/99, standing 151/106 mmHg). Heart rate was transiently increased by nitrendipine 20 mg once daily and unchanged following amiloride. Plasma noradrenaline was unaltered following amiloride 10 mg once daily as well as nitrendipine 20 mg twice daily, whereas plasma renin activity and aldosterone were elevated following amiloride. Serum electrolytes, blood glucose, plasma lipids and body weight were not altered by any of the drugs. Amiloride 5-10 mg daily has a mild to moderate BP lowering effect in patients with essential hypertension. The BP reduction following nitrendipine 20 mg once daily was comparable to that of amiloride 5 mg daily. Nitrendipine 20 mg twice daily gave no additional BP decrease.