Long‐term treatment of hypertension with labetalol.

Self Cite

1 The anti‐hypertensive effects of labetalol have been compared and contrasted with other groups of anti‐hypertensive drugs in this review of the published literature. 2 The data show that the pharmacological and haemodynamic profile of labetalol in man is distinctly different from that of other specific anti‐hypertensive agents; namely the properties of competitive alpha‐and beta‐adrenoceptor blockade leading to haemodynamic effects of reduced blood pressure and peripheral vascular resistance with little accompanying changes in resting heart rate or cardiac output. 3 The anti‐hypertensive effects of labetalol are dose related. In fixed dose comparative studies equivalent anti‐ hypertensive effects to those of labetalol have been shown for individual drugs of the beta‐adrenoceptor‐blocking and diuretic groups. In dose titration studies, equivalent anti‐hypertensive effects at given doses of labetalol have been demonstrated for drugs of the following types: beta‐adrenoceptor blockers, beta‐blockers plus diuretics, methyldopa, adrenergic neurone blockers and the combination of beta‐blockers plus a peripheral vasodilator. 4 Comparing side‐effect liabilities, it is clear that quantitatively labetalol produces no greater burden of side‐effects than drugs of the beta‐adrenoceptor‐ blocking group. Qualitative differences, however, do exist; in particular, symptomatic postural hypotension is dose related and is more likely to occur when excessive doses (greater than 2 g daily) are used.

“…Labetalol has been used in combination with diuretics since the earliest clinical studies (Prichard & Boakes, 1976;Bolli et al, 1976).…”

Section: Labetalol and Diureticsmentioning

confidence: 99%

Comparison of labetalol with other anti‐hypertensive drugs.

Prichard¹,

Richards²

1982

Self Cite

“…It was anticipated that this mechanism of action would cause excessive falls of blood pressure on standing or exercise by comparison with lying determinations, as seen with adrenergic-neurone blocking drugs (Prichard, Johnston, Hill & Rosenheim, 1968) or combined administration of potent a-and #-blocking adrenoceptor drugs such as phenoxybenzamine and propranolol (Beilin & Juel-Jensen, 1972). However, Prichard & Boakes (1976) reported that postural exacerbation of blood pressure reduction occurred only with doses of labetalol in excess of 1.8 g daily. By contrast other early reports (Pugsley, Armstrong, Nassim & Berlin, 1976;Bolli, Waal-Manning, Wood & Simpson, 1976) suggested that in patients previously treated with diuretics, smaller doses of labetalol showed increased anti-hypertensive effects on standing or after exercise.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, a study was designed to determine the effects of combination treatment with labetalol and a diuretic, and to compare them with those of each individual drug. As postural exacerbation of blood pressure was reported by Prichard & Boakes (1976) to be dose related, two dose levels of labetalol were studied.…”

Section: Introductionmentioning

confidence: 99%

A comparison of the effects of labetalol, bendrofluazide and their combination in hypertension.

Dawson¹,

Bf²,

Smith³

et al. 1979

1 Bendrofluazide (10 mg/day) or labetalol (300 mg and 600 mg/day) produced significant reductions in lying, standing, and post-exercise blood pressure in ten hypertensives. 2 Active treatments were approximately equivalent in anti-hypertensive effect. However, comparing lying and standing determinations, labetalol (600 mg/day) produced significantly greater additional postural falls in systdlic blood pressure than during placebo or bendrofluazide treatment. 3 Systolic blood pressure rose after exercise during placebo or bendrofluazide treatment. However, on labetalol, mean changes in systolic blood pressure after exercise were negative and significantly different from those seen on placebo. 4 Greater reductions in lying and post-exercise systolic blood pressure were produced by combination treatment than by either individual drug. Additional postural and exercise-related falls in systolic blood pressure tended to be smaller with combination treatment than during treatment with labetalol alone. 5 Labetalol significantly reduced lying, standing, or post-exercise heart rate by comparison with placebo or bendrofluazide. 6 Labetalol moderately reduced plasma renin activity, whereas bendrofluazide caused marked elevation. The effect of bendrofluazide predominated during combination treatment.

“…In animal and human studies this drug has been found to decrease systemic vascular resistance and, thus, arterial blood pressure, only moderately slowing down heart rate (Brittain & Levy, 1976; Richards, 1976;Koch, 1977;Mehta & Cohn, 1977). Labetalol has been successfully used in the treatment of hypertension (Mehta & Cohn, 1977;Frick & Porsti, 1976;Prichard & Boakes, 1976); however, for the reasons mentioned above, it is conceivable that this drug could be beneficial also in coronary artery disease, independent of its anti-hypertensive action.…”

Section: Introductionmentioning

confidence: 99%

Effects of combined alpha‐ and beta‐blockade by labetalol in patients with coronary artery disease.

Condorelli¹,

Brevetti²,

Chiariello³

et al. 1982

1 The effect of labetalol 100 mg orally twice daily on exercise tolerance has been compared with placebo in 19 normotensive subjects with angiographic evidence of coronary artery disease. 2 Labetalol, at the same work load as during placebo exercise, significantly reduced systolic and diastolic blood pressures, as well as heart rate and rate-pressure product. 3 Similarly, ST segment depression was reduced by labetalol from 2.0 ± 0.4 to 1.36 ± 0.6 mm (P<0.001), thus enabling an increase in exercise tolerance from a control value of 83.7 ± 18 to 95.3 ± 19 W (P<0.005). 4 In seven other patients, also with coronary artery disease, the haemodynamic effects of a single 0.6 mg/kg intravenous dose of the drug was evaluated during exercise. 5 Compared with conditions during control exercise, labetalol induced a significant reduction in rate-pressure product from 17228 ± 2375 to 13445 ± 2404 mmHg/min (P<0.005) and in peripheral vascular resistance from 612.0 ± 61.2 to 512.7 ± 36.2 dyn cm-5 m-2 (P<0.0025). These events were not accompanied by any change in cardiac index and in dP/dT left ventricular end-diastolic pressure (LVEDP) ratio. 6 These data suggest that labetalol may induce reduction in myocardial oxygen consumption, thereby increasing exercise tolerance in patients with coronary artery disease, without impairment of left ventricular performance.