Beta blockade in essential hypertension: an analysis of response to oxprenolol.

Abstract

The data from 40 patients with essential hypertension treated with oxprenolol alone have been used to analyse the falls of blood pressure and heart rate. Blood pressure and heart rate did not fallfurther as the daily dose was increased above 160 mg. The range offall in mean pressure was from 0 to 40 mmHg and there was no clear separation into response groups. Pressure falls were unrelated to sex, age, initial heart rate, increase in heart rate on standing, the fall of heart rate with the drug, or the initial height of blood pressure. In the absence of predicting factors the use of oxprenolol, and, by deduction, other beta blocking agents, in hypertension remains empirical, but the simplification of the dose range allows the response to oxprenolol to be determined quickly.All beta blocking drugs which have been tested in hypertension have been shown to have a hypotensive effect. In two trials propranolol, practolol, oxprenolol, metoprolol, timolol, pindolol, alprenolol, and tolamolol were found to be effective hypotensive agents (Morgan et al., 1974;Davidson et al., 1976), and it appears to be the case that the possession of attributes such as cardioselectivity, intrinisic sympathomimetic activity, and membrane stabilising activity are irrelevant in this respect.Several important aspects of the use of beta blockade await clear definition. For instance, there is dispute about the dose range to be employed with the most used agents, propranolol and oxprenolol. Dose ranges for propranolol have been quoted from 10 to 4000 mg daily (Prichard and Gillam, 1969), whereas in a recent study no benefit from doubling the dose from 120 to 240 mg daily was found (Galloway et al., 1976 Patients and methodsForty patients with essential hypertension were studied. The mean systolic blood pressure was 175 SD ± 20 and diastolic 111 SD ± 9 mmHg. The trials in which they took part have previously been reported (Marshall and Barritt, 1973;Barritt et al., 1976). Seventeen were men, and 23 were women, and their age range was from 30 to 73 years. Renal disease was excluded by examining the abdomen, testing the urine for albumin, and measuring blood urea and electrolytes. Endocrine hypertension was excluded by clinical examination and measurement of urinary catecholamine excretion. The presence of obstructive airways disease, cardiac failure, or hypertensive complications requiring immediate treatment, were reasons for exclusion. All the patients were new hypertensives who had received no previous treatment, and received no other hypotensive agent during the period of study.After the initial assessment they attended a clinic specially set aside for the study. Every patient attended this clinic on 4 occasions at weekly intervals before starting treatment. Each patient was seen throughout by the same physician and the blood pressure was measured blindly using the London School of Hygiene and Tropical Medicine sphygmomanometer. Blood pressure was measured after 5 825

Evaluation of indoramin added to oxprenolol and bendrofluazide as a third agent in severe hypertension.

“…Our previous experience suggests that there is usually little to be gained by increasing the daily dose of either drug (Barritt & Marshall, 1977;Marshall et al, 1977). They required a third agent and indoramin was added.…”

Antihypertensive and hemodynamic effects of oxprenolol versus propranolol

“…14,22,39,61,62 Although not yet accepted in the United States, oxprenolol has also been reported to be an effective antihypertensive agent in numerous studies from this country'" and abroad." 4,25,28,36,50,53 In view of claims that oxprenolol appears to be as good as propranolol as an antihypertensive, 1 an antianginal,": 42 and possibly even an antiarrhythmic agent, 16,32,51 but with substantially less negative inotropic effects;": 24, 3t. 45 interest in oxprenolol is understandable.…”

Oxprenolol Hydrochloride: Pharmacology, Pharmacokinetics, Adverse Effects and Clinical Efficacy

“…Some studies looked at patient factors that may be predictors of response to the blood pressure lowering effect of o x p r e n 0 1 0 1 .~~~~~~~~ They found that patients who did not adequately respond to doses under 200 mg daily were not likely to have greater reductions in blood pressure as the dose was increased. The largest daily dose used was 1,260 mg in the series of Barrett et al 64 This group also found that there was no relationship between blood pressure effect and age, sex, initial heart rate, percentage increase in heart rate upon standing, percentage decrease in heart rate with beta-blockade or initial blood pressure, although pretreatment blood pressures greater than 200 mm Hg/l15 mg Hg were difficult to normalize with oxprenolol alone. As mentioned previously, reduction in PRA did not correlate with reduction of blood pressure.…”