Effect of potassium supplementation in hypertensive patients with diuretic-induced hypokalaemia: changes in bloodpressure and red cell sodium content - abstract

ABSTRACT

Hypokalaemia is a frequent accompaniment of chronic diuretic therapy of hypertension. It is associated with an increased risk of cardiac arrhythmias as well as several biochemical abnormalities. Potassium supplementation produces a rise in serum potassium level and a fall in the mean blood pressure. The mechanisms underlying the changes in blood pressure with changes in body potassium status are ill understood but might involve changes in cell electrolytes. We therefore measured red cell sodium and potassium content in hypertensive patients during diuretic-induced hypokalaemia and after potassium supplementation. Eleven patients were treated with bendrofluazide (10 mg daily) for a monthe before measurements of serum and urine potassium, blood glucose level, uric acid and red cell sodium and potassium concentrations were made. Potassium chloride (60 mmol/day) was added for another month and the same measurements repeated. Red cell electrolyte content was measured by flame photometry after isolating the cells by density centrifugation. Mean blood pressure fell (103 ñ 3 to 95 ñ 3mm hg, p<0.005) with the change in serum potassium level from 3.1 ñ 0.1 to 4.1 ñ 0.3 meq/l(p<0.05). Red cell sodium content fell from 13.8 ñ 1.4 to 10.8 ñ 1.3 mmol Na/l RBC while potassium content was unchanged 90.7 ñ 8.6 vs 81.1 ñ 7.2 (p>0.10). Insignificant reductions in blood glucose and uric acid levels occurred. The fall in cell sodium concentration could contribute to the fall in blood pressure if similar changes occurred in vascular smooth muscle cells. Potassium supplementation enhance blood pressure control in hypokalaemic hypertensives (AU)