EFFECTS OF HYDROCHLOROTHIAZIDE, DILTIAZEM AND ENALAPRIL ON MONONUCLEAR CELL SODIUM AND MAGNESIUM LEVELS IN SYSTEMIC HYPERTENSION

Sixteen patients (mean age 68 years) with mild to moderate hypertension were treated with either diltiazem or hydrochlorothiazide for 6 weeks, followed by enalapril for a further 6 weeks. A second group of 40 patients (mean age 71 years) was treated with either hydrochlorothiazide or enalapril for 12 weeks; nonresponders received both drugs for 8 weeks. Treatment with hydrochlorothiazide or enalapril resulted in a lowering of systolic and diastolic blood pressures, but diastolic pressure was lower in patients treated with enalapril (89 +/- 2 and 82 +/- 2 mm Hg, respectively; p < 0.05). Treatment with diltiazem resulted in a decrease in diastolic pressure only. Treatment with hydrochlorothiazide resulted in a 17% decrease in serum potassium (p < 0.05), which returned to normal when enalapril was substituted. Hydrochlorothiazide also produced a 23% decrease in mononuclear cell sodium content at 4 weeks (p < 0.01), with a further 15% decrease at 12 weeks (p < 0.05). Mononuclear cell potassium and magnesium also decreased at 12 weeks by 18 and 16%, respectively (p < 0.05). All these effects were reversed when enalapril was substituted. A similar pattern of events was seen with diltiazem, which was again reversed with enalapril. Finally, there was no relation between changes in mononuclear cell sodium or other cation content and changes in blood pressure.