Potassium supplementation in the treatment of idiopathic postural hypotension

We studied the effects of potassium supplementation (60 mmol/day) and matching placebo on the postural blood-pressure fall in ten elderly patients with symptomatic idiopathic postural hypotension in a double-blind, randomized cross-over trial. There was a significant decrease in the orthostatic fall in systolic blood pressure (SBP 33 +/- 5 mmHg to 16 +/- 9 mmHg, p less than 0.01) and in supine SBP (162 +/- 7 to 150 +/- 7 mmHg, p less than 0.01) between placebo and potassium phases. Supine diastolic and erect blood pressures were unchanged, though pulse rate showed a greater orthostatic increase (7 +/- 3 beats/min to 14 +/- 2 beats/min, p less than 0.05) following potassium therapy. No significant changes were seen in intracellular electrolytes, plasma renin activity, aldosterone levels or body weight. Seven patients reported symptomatic improvement with potassium, but none during the placebo phase. Potassium therapy was well tolerated and may be a successful and safe method of treating idiopathic postural hypotension.