From the limited available evidence, spironolactone appears to lower blood pressure compared to placebo to a similar degree in patients with primary (essential) hypertension when doses of 100-500 mg/day are given. A dose of 25 mg/day did not statistically significantly reduce systolic or diastolic blood pressure, compared to placebo. Given the lack of a dose-response, coupled with a possible increased risk in adverse events with higher doses, doses of 25 to 100 mg/day are reasonable. There is no evidence of the effect of spironolactone on clinical outcomes in hypertensive patients.
Treatment of arterial hypertensive disease with diuretics. V. Spironolactone, an aldosterone antagonist.