[Hemodynamic changes under metoprolol compared to propranolol in hypertensive patients]

The effect of the new beta-receptor-blocking drug metoprolol on hemodynamics and plasma renin activity was studied at rest and during exercise. 5 patients with essential hypertension were investigated before, 4 weeks after and 8 weeks after oral treatment (3 X 50 mg day). The results were compared to data of 5 patients under propranolol matched according to age, arterial blood pressure, and renin concentration. Metoprolol leads to a significant fall in renin and heart rate, whereas cardiac index is depressed only during exercise. Peripheral resistance remains unchanged and left ventricular filling pressure rises slightly. This results in a slight fall in arterial blood pressure. In comparison with propranolol the hemodynamic and renin patterns under metoprolol are similar, the only difference being the slighter fall in blood pressure due to a less depressed cardiac index.

An eighteen months' study of the clinical response to metoprolol, a selective beta1-receptor blocking agent, in patients with angina pectoris

Following an initial dose response study, metoprolol, a selective beta1-receptor blocking agent, was compared with equipotent dosages of propanolol in a double blind cross-over study, including exercise tolerance tests, on fourteen patients with angina pectoris. Long term therapy with metoprolol then followed until the seventy-second week. Patients performed 8% more total work on metoprolol with 15% more work recorded up to the onset of S-T depression, in comparison with propranolol. In the long term, ther was no significant difference in work performed when the daily dosage of metoprolol was changed from a q.i.d. to a b.d. regime. Metoprolol was shown to be an effective anti-anginal compound with good tolerance and safety, with gradual improvement in underlying myocardial ischaemia during long term treatment.

Comparison of metoprolol as hydrochlorothiazide and antihypertensive agents

A crossover comparison of metoprolol and hydrochlorothiazide has been performed in 20 patients with mild hypertension. Both drugs caused almost identical statistically significant reduction in blood pressure of about 20 mm Hg systolic and 15 mm Hg diastolic. The side effects during active therapy were few and mild, but 5 patients experienced subjective symptoms during the first few days following abrupt withdrawal of metoprolol, namely general malaise, palpitations, headache, sweating and tremor. The symptoms were more pronounced in the standing position and disappeared at once on resumption of beta-blocker therapy, or gradually over 5 - 7 days when placebo tablets were given. In 11 of the 20 patients hydrochlorothiazide produced subnormal serum potassium levels and potassium supplements were given. The serum uric acid level was also significantly increased during hydrochlorothiazide treatment.

Assessment of metoprolol, a cardioselective beta-blocking agent, during chronic therapy in patients with angina pectoris

Ten patients with typical angina pectoris and without hypertension, congestive heart failure or other disease were treated with alternating four-week courses of metoprolol (alpha beta1 cardioselective beta-blocking agent), propranolol and placebo. Midway through each four-week period, drug dosage was doubled; thus, regimes were metoprolol, 150 and 300 mg/day, propranolol, 120 and 240 mg per day and placebo, 3 and 6 tablets per day. Serum concentrations of metoprolol increased with increasing dosage in a proportion very similar to that seen with propranolol. Statistically significant reductions in angina frequency/nitroglycerin consumption, and statistically significant increases in total work performed on a bicycle ergometer, were found with both active compounds when compared with placebo. No significant differences were noted between the two active compounds. Though most patients showed greatest improvement on the higher of the two drug dosages, three patients with metoprolol and two with propranolol responded best on the lower dose regime. Both compounds reduced heart rate at rest and during exercise. Neither reduced arterial pressure at rest, but both reduced arterial pressure during exercise. It is concluded that metoprolol is as effective as propranolol in the reduction of angina attacks and improvement in exercise tolerance during chronic therapy in patients with uncomplicated angina pectoris. It is now appropriate to study the effects of metoprolol in patients with coronary artery disease in whom the harmful effects of non-selective beta-blockade heretofore have precluded optimal therapy with beta-blocking drugs.

Comparative study of metoprolol and alpha-methyldopa in untreated essential hypertension

The hypotensive actions of metoprolol and alpha-methyldopa have been compared in 37 men with previously untreated essential hypertension; 36 belonged to stage 1 and 1 to stage 2 of the WHO classification. After four weeks of placebo treatment the patients were randomly allocated to treatment with either of the two drugs. Treatment was started with metoprolol 75 mg daily or alpha-methyldopa 375 mg and was doubled after eight weeks. Satisfactory blood pressure control was defined as systolic blood pressure below 160 mm Hg and diastolic below 95 mm Hg. The patients were examined every four weeks and in those with unsatisfactory control the dose was gradually increased up to a maximum daily dose of metoprolol 450 mg or alpha-methyldopa 2250 mg. The trial lasted for 24 weeks after randomization. Five patients dropped out of the study. After six months, satisfactory blood pressure control was recorded in 16 out of 17 patients and 14 out of 15 patients treated with metoprolol and alpha-methyldopa, respectively. The average reduction in blood pressure produced by the two drugs was comparable. One patient in the alpha-methyldopa group developed drug exanthema and two patients a positive Coombs' test. Other side effects were few and did not differ between the two compounds.