Comparison of intravenous dilevalol with placebo in moderate hypertension.

Dilevalol, an agent that combines nonselective beta-blocking and beta 2-mediated vasodilating properties, was compared with placebo in 16 subjects with moderate hypertension in a double-blind crossover study. Dilevalol or a placebo was administered intravenously in bolus injections of 25, 50, and 50 mg at 15-minute intervals. Fifteen minutes after a cumulative dose of 125 mg, the blood pressure was lowered by 11/9 mm Hg, compared with 2/1 mm Hg after placebo (p less than 0.

Labetalol compared with propranolol in the treatment of black hypertensive patients.

A double-blind parallel group study was conducted to examine the effects of oral labetalol, in doses from 100 to 800 mg BID, and propranolol, 40 to 320 mg, in patients with mild to moderate hypertension. The doses of labetalol (n = 74) and propranolol (n = 79) were titrated weekly to achieve a sitting diastolic blood pressure (DBP) of less than 90 mmHg or at least a 10-mmHg decrease from placebo baseline on two consecutive visits. A 2-month fixed-dose maintenance phase followed in which a diuretic could be added if the sitting DBP was greater than or equal to 100 mmHg on maximum doses of either drug.

Effect of single doses of labetalol, metoprolol, and placebo on ventilatory function in patients with bronchial asthma: interaction with isoproterenol.

The effects of labetalol, metoprolol, and placebo on pulmonary function and their interaction with isoproterenol were evaluated in 18 patients with reversible bronchial asthma [isoproterenol-induced increase in forced expiratory volume in 1 second (FEV1) of greater than or equal to 15%]. Two dose levels of each medication were studied (on consecutive days), with the lower doses of these drugs given randomly. When the lowest values during the 2-hour postdrug evaluation period were considered, FEV1 significantly increased (10.

Pharmacodynamics of intravenous labetalol and follow-up therapy with oral labetalol.

The effectiveness, safety, and pharmacodynamics of repeated doses of intravenous labetalol for rapid reduction of severe hypertension and of subsequent oral labetalol dosing were studied. Twelve patients with severe hypertension were admitted to the hospital after the withholding of antihypertensive therapy for 2 to 14 days. Thirty minutes after an injection of vehicle only, labetalol, 0.

The effects of treatments with labetalol and hydrochlorothiazide on ventilatory function of asthmatic hypertensive patients with demonstrated bronchosensitivity to propranolol.

Fifty-two asthmatic patients with mild to moderate hypertension were screened for bronchosensitivity to propranolol in a double-blind randomized fashion after a 2-week minimum placebo run-in period. Thirty-five patients qualified on the basis of a decrease in 1-second forced expiratory volume FEV1 by greater than or equal to 20% after 80 mg of propranolol with no more than a +/- 15% change after placebo. Of these patients, 18 were then randomly assigned to antihypertensive treatment with labetalol at doses that were increased at weekly intervals (100, 200, 400, 600 mg BID) and 17, with hydrochlorothiazide (HCTZ) (25 or 50 mg BID) as needed for control of hypertension.

Step II treatment with labetalol for essential hypertension.

Labetalol, a new alpha- and beta-adrenergic blocking agent, was administered to 57 patients with essential hypertension whose standing diastolic blood pressure was 105 to 120 mm Hg after three and four weeks of placebo therapy and greater than 90 mm Hg after three to four weeks of therapy with hydrochlorothiazide, 25 mg twice a day. Patients were then randomly assigned on a double-blind basis to receive either labetalol, 100 mg twice a day, or placebo combined with hydrochlorothiazide. Thereafter, the dose of labetalol was titrated weekly in both groups to a maximum of 400 mg twice a day to achieve a standing diastolic blood pressure of less than 90 mm Hg that was also decreased from the hydrochlorothiazide baseline by 10 mm Hg or more (therapeutic goal).

Monotherapy with labetalol in the treatment of mild hypertension: a double-blind study.

The antihypertensive effects of oral labetalol compared with placebo were evaluated in 74 mildly hypertensive patients (standing diastolic blood pressure 95 to 110 mm Hg) in a bicentric double-blind parallel group study. Following a four-week placebo phase, 36 patients were randomly assigned to receive labetalol and 38 to receive placebo. A five-week titration phase followed during which the dose of labetalol was increased weekly from 100 mg twice a day to 600 mg twice a day to achieve a standing diastolic blood pressure of less than 90 mm Hg and decreased 10 mm Hg or more from baseline.

Study of single and multiple dose pharmacokinetic/pharmacodynamic modeling of the antihypertensive effects of labetalol.

This was an open-label, two-phase crossover study of labetalol in 11 patients with mild to moderate hypertension. A two- to four-week outpatient placebo phase was followed by a three-day inpatient placebo period. Patients were then randomly assigned to receive either labetalol, 200 mg, as a single dose and three times a day for three days and, on the final day, another single dose or a similar sequence with 300 mg as the single dose and multiple twice a day treatment.

Pharmacological effects of urotensins. IV. Blood pressure-lowering effects of urotensin I in spontaneously hypertensive rats.

The blood pressure lowering effect of urotensin I, a vasodilatory peptide obtained from urophyses of a bony fish species (Catostomus commersoni) was studied by tail plethysmography in conscious normotensive and in spontaneously hypertensive rats. Urotensin I (10 mU/100 g body weight i.v.

Pharmacological effects of urotensins. III. Fate or Urotensin I in different vascular beds and in blood of the rat.

The rates of disappearance of urotensin I, a peptide with a prolonged vasodepressor action, was studied in perfused isolated organs of the rat and in rat blood in vitro. The rates ranged from 29.9+/-3.

Pharmacological effects of urotensins. II. Renal effects of urotensin I in the rat.

Urotensin I decreased urine flow, glomerular filtration rate and renal plasma flow in intact and hypophysectomized rats. The antidiuretic effect of urotensin I differed from the that caused by AVT in that (a) the urine conductivity was not usually increased by the former, and (b) the rates of excretion of Na and K were different. The use of hypophysectomized rats and of Na-thioglycollate-treated urotensin I preparations indicated that the antidiuretic effect of urotensin I was not due to the release of endogenous ADH, nor was it caused by presence of AVT in the urotensin I samples.

Pharmacological effects of urotensins. I. Regional vascular effects of urotensins I and II in the rat.

The effects of urotensins I and II were studied on blood space and inulin space (with 51Cr-labelled erythrocytes and 14C inulin) in organs obtained from rats anaesthetized with pentobarbital. The findings were matched with the effects of urotensins on blood pressure and on perfusion pressure in the isolated perfused rat hind limb (skeletal muscle), intestine, kidney, and lung. Blood space was greatly increased by urotensin I (50 mU/100 g body wt iv) in skeletal muscle, intestine (ileum), ear, renal cortex, medulla and papilla and in adrenal gland, but was decreased in liver and spleen.

Pharmacological observations on the hypotensive action of extracts of teleost fish Urophyses (urotensin I) in the rat.

1 Intravenous injections of urotensin I regularly caused a long-lasting, dose-related, lowering of blood pressure and an increase in heart rate in conscious rats, or a reduction in perfusion pressure in the isolated hind limb of the rat.2 After subcutaneous administration, the hypotensive effect of urotensin I was greater in extent and in duration (> 24 hours).3 Anaesthesia with ether, chloralose, pentobarbitone and thiobarbitone caused a decrease in blood pressure and only slightly diminished the hypotensive effect of urotensin.