Treating hypertension. The place of beta blockade

The effects of a beta 1-blocking agent, atenolol, on blood pressure, plasma renin activity and prostaglandin F2 alpha excretion in patients with essential hypertension

The antihypertensive action of beta-blocking agents has been suggested to be associated with the decrease in plasma renin activity (PRA) and can be antagonized by indomethacin, a prostaglandin (PG) synthesis inhibitor. We studied the acute and long-term effects of a beta 1-blocking agent, atenolol (50 mg b.i.d.), on blood pressure (BP), PRA and urinary PGF2 alpha excretion in 12 male patients (40 years old) with essential hypertension. BP was measured by means of a brachial cuff. PRA and PGF2 alpha were estimated radioimmunologically. One day after the initiation of atenolol treatment, BP fell significantly, the supine values from 159/114 to 143/104 mmHg and the erect from 158/118 to 140/106 mmHg. In six weeks BP decreased further to 135/94 and 134/96 mmHg, respectively. After the cessation of atenolol for three weeks BP rose to the pre-atenolol level. When the dose was readjusted (25-150 mg daily for 26 weeks), diastolic BP remained at 100 mmHg or higher in only two patients. During the atenolol treatment PRA declined to one-third of the pre-atenolol level in one day and to one-half in six weeks. The urinary excretion of PGF2 alpha was not affected by atenolol. Our results suggest that 1) the antihypertensive action of atenolol and the reduction of PRA are substantial already in one day, and 2) the decrease in BP or PRA is not associated with PGF2 alpha production.

Long-term treatment of essential hypertension with Nadolol and Hydrochlorothiazide: a two-year follow-up

After 3 weeks of placebo administration, thirty-two mildly or moderately hypertensive patients were treated with hydrochlorothiazide (HCZ) for 3 weeks, then with HCZ plus nadolol, a new beta-adrenergic blocker, for 2 years. The dose of HCZ was 50 mg once daily for all except two patients, who received 50 mg twice a day. The dose of nadolol ranged from 40 mg to 240 mg, once daily. The average supine blood pressure decreased from 182/110 mm Hg at the end of the placebo period to 170/104 mm Hg at the end of treatment with HCZ alone. Nadolol was added to the regimen, and the average supine blood pressure decreased further to 132/88 mm Hg at the end of 3 months of combined therapy. It remained essentially unchanged for the duration of the 2-year study, and no increases in the dosage of either drug were needed. Side-effects were mild, and none required a change in dosage. A once-daily dose of nadolol combined with HCZ appears to be safe and effective therapy for the long-term treatment of mild or moderate essential hypertension.

Comparison of labetalol and propranolol in hypertension

1 Labetalol has been compared with propranolol in a double-blind, double-dummy study of 24 patients with mild or moderate essential hypertension. 2 Two patients were unable to tolerate propranolol and five labetalol, because of symptom side effects; this difference was not significant (P greater than 0.1). 3 On a self-administered questionnaire, labetalol was associated with a greater number of side effects per patient than propranolol, but no individual side effect was significantly more common with either drug. 4 There was no difference in the number of spontaneously reported side effects between the two drugs. 5 Both drugs impaired pulmonary function, but propranolol caused a greater reduction than labetalol after 8 weeks of treatment. 6 We conclude that labetalol and propranolol are similarly effective and acceptable to the patient.

Antihypertensive efficacy of propranolol given twice daily

The therapeutic efficacy of propranolol in four and two daily doses was compared in 63 treated hypertensive patients in a multicentre trial. After 3 months of a stable diastolic blood pressure while receiving propranolol four times a day the patients were switched to a twice-a-day regimen, the drug being given at 8 am and 8 pm, with the same total daily dose, for 3 more months. Blood pressures and heart rates were measured at 8 am, 12 noon, 4 pm and 8 pm at 4-week intervals. There were no significant changes in mean blood pressure after the change to the twice-a-day regimen, although some patients reported new side effects. Compliance appeared to be unaffected.