Intraerythrocyte sodium content and transmembrane sodium flux in hypertensive patients treated with diuretics or β‐adrenoceptorblockers

: Forty-seven male patients with essential hypertension were randomized to treatment with either a s-adrenoceptorblocker (metoprolol), (n = 24), or a diuretic (hydrochlorothiazide), (n = 23). If their diastolic blood pressure was not lowered below 95 mm Hg by the maximum dose of either drug, hydralazine (15 patients) and in a few cases (6 patients) spironolactone was given. After five years of treatment all the patients were examined with respect to intraerythrocyte sodium (IeNa) and potassium (leK). sodium influx and sodium efflux. Patients treated with the diuretic (D) tended to have a higher leNa (9.8±0.4 mmol/l red cells) and sodium influx (0.044±0.002 mmol Na/1 X min) compared with those taking the s-adrenoceptoblocker (B) (8.9±0.3 mmol/l and 0.041±0.002 mmol Na/l X min). but neither of these differences was statistically significant. Sodium efflux, however, was significantly increased in D (0.073+0.003 mmol Na/l X min vs 0.061 ± 0.003 mmol/l X min). No difference in leK was noted between the two groups. Six patients taking spironolactone had a low leNa (7.3±0.4 mmol/l), sodium influx (0.039±0.001 mmol Na/l X min) and sodium efflux (0.050±0.006 mmol Na/l X min).