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At least 19 recordsLinked to original sources
PubMed1975

Long term treatment of moderate hypertension with penbutolol (Hoe 893d). I. Effects on blood pressure, pulse rate, catecholamines in blood and urine, plasma renin activity and urinary aldosterone under basal conditions and following exercise.

The effects of penbutolol (Hoe 893 d), a new non-selective beta-receptor blocking agent, were studied in 5 patients with moderate hypertension. Initially, it was shown that 2-4 mg given orally once or twice daily tended to lower blood pressure and pulse rate, both at rest and following submaximal work. In prolonged trials (3-8 months) 4-60 mg/day were required to produce an acceptable antihypertensive effect. Penbutolol had no effect on the normal increase in plasma noradrenaline and adrenaline on standing, nor did it alter basal urinary catecholamine excretion. Submaximal work caused no significant change in plasma catecholamines before treatment, but there was a marked rise both in plasma noradrenaline and adrenaline during treatment with penbutolol. In short term studies there was a fall in plasma renin by 4 hours after oral administration of penbutolol 2-4 mg, which persisted for 24 hours. Prolonged treatment with penbutolol 20-30 mg twice daily inhibited renin production under basal conditions and following submaximal work, as well as lowered basal urinary aldosterone excretion. In one patient slight asthmatic symptoms appeared after treatment for 3 months with penbutolol. In other respects penbutolol was well tolerated.

Adrenergic beta-Antagonists↗
PubMed1977

Comparative beta-adrenoceptor blocking effects and pharmacokinetics of penbutolol and propranolol in man.

1 The beta-adrenoceptor blocking effects of penbutolol were compared with those of propranolol and a placebo in a double-blind trial involving six healthy volunteers. 2 Heart rate (HR), systolic blood pressure (SBP) and peak expiratory flow rate (PEFR) were measured at rest and during vigorous exercise before and at intervals up to 7 h after oral administration of the drugs. In addition, plasma renin activity (PRA) at rest and plasma levels of penbutolol and propranolol were determined. 3 Penbutolol proved to be a non-cardioselective beta-adrenoceptor blocking drug, antagonizing exercise-induced tachycardia, reducing exercise-induced increase in PEFR and decreasing PRA. The beta-adrenolytic potency of penbutolol was shown to be four-fold that of propranolol but the duration of its effect was similar. 4 The peak plasma level of penbutolol was reached 1 h after administration and its half-life was 4.5 h. 5 Comparison of plasma levels and biological activity of penbutolol revealed that after oral administration this drug is transformed into an active metabolite in man.

Adrenergic beta-Antagonists↗
PubMed1978

Comparative potency of intravenous penbutolol and propranolol in man.

A study on the comparative potency of intravenously administered penbutolol, a new non-selective beta adrenoceptor antagonist, on the resting and post-exercise heart rate and rate-pressure product was carried out in 5 normal human subjects. The effects produced by 0.1, 0.2 and 0.3 mg of penbutolol and of 0.025 mg/kg (mean dose 1.28 mg) of propranolol was recorded. The dose of penbutolol producing an effect equivalent to that of propranolol was calculating from the log dose-response curve of penbutolol. In these tests, penbutolol was 7.90 and 7.66 times more potent than propranolol on a weight to weight basis. Penbutolol was well tolerated and no side-effects were observed.

Adrenergic beta-Antagonists↗
PubMed1979

Single and divided doses of penbutolol.

Penbutolol, a nonselective beta-adrenoreceptor antagonist, induced reduction of exercise-induced heartbeats for at least 24 hr after a single 40-mg oral dose, and was equipotent with respect to a 2 X 20-mg regimen over the same period. Ingestion for 7 days did not influence the pharmacodynamics or pharmacokinetics of penbutolol, and there was no cumulation of drug in serum. A relationship was found between the logarithms of measurable serum concentrations of penbutolol and the percentage reduction of total heartbeats. Absorption of oral penbutolol appeared to be reduced when administered in the evening. Since beta-adrenoceptor activity was relatively unchanged between 13 and 24 hr after a single 40-mg dose of penbutolol, there is a possibility that an active metabolite or metabolites may contribute to prolonged duration of action.

Adult↗
PubMed1979

Antiarrhythmic effects of L-penbutolol and DL-propranolol. Comparison of the effects of these two drugs on conductivity and excitability in canine heart in vivo.

The effects of l-penbutolol and dl-propranolol on A-V conduction, on excitability of ventricular muscle, and on ventricular tachycardia threshold in acute ischemia were compared, using anesthetized dogs. 1. L-penbutolol (100 microgram/Kg) and dl-propranolol (100 microgram/Kg) prolonged A-V conduction and reduced excitability of ventricular muscle significantly. L-penbutolol less prolonged A-V conduction than dl-propranolol. 2. Both l-penbutolol (50 microgram/Kg) and dl-propranolol (50 microgram/Kg) significantly prevented the lowering of ventricular tachycardia threshold in acute ischemia. These beta-blocking drugs are effective in the treatment of arrhythmia and l-penbutolol could be used safely, because of its weaker inhibition on A-V conduction.

Animals↗
PubMed1976

A double-blind trial of penbutolol: a new beta-receptor blocking agent in the treatment of angina pectoris.

A double-blind placebo controlled study of angina pectoris with penbutolol was undertaken in parallel groups in fifty-two patients. The duration of the study was six weeks. The dosage range for penbutolol was 8 mg to 50 mg per day. Six patients were dropped from the analysis. Seventeen patients (81%) in the penbutolol series exhibited a 50% reduction in anginal attacks, NTG consumption and subjective improvement. Significant reduction in nitrite intake was observed. Effort tolerance was improved significantly in those receiving penbutolol. Penbutolol was well-tolerated.

Adrenergic beta-Antagonists↗
PubMed1979

Intrinsic sympathomimetic activity of penbutolol.

Six healthy volunteers took part in a randomized, single-blind, crossover study to quantitate the intrinsic sympathomimetic activity (ISA) of penbutolol in comparison with one drug possessing ISA (alprenolol) and with the standard non-ISA drug (propranolol). Single intravenous and one week oral administrations were studied. Complete parasympathetic and sympathetic isolation of the heart was obtained by administration of atropine 0.04 mg/kg body weight i.v. and propranolol 0.4 mg/kg i.v., or corresponding equipotent doses of alprenolol 0.4 mg/kg i.v. and penbutolol i.v. 0.08 mg/kg. In the chronic, oral study propranolol 160 mg b.i.d. was given, or corresponding equipotent doses of alprenolol (400 mg b.i.d.) or penbutolol (40 mg b.i.d.). The test procedure included measurement of heart rate and blood pressure in the supine, sitting and standing positions, and during isometric and dynamic exercise. ISA was calculated by comparison of the change in of heart rate with that produced by propranolol. The ISA of alprenolol was 22--26% and of penbutolol 12--18% of maximal sympathetic activity. Isometric and dynamic exercise gave comparable ISA values.

Adrenergic beta-Antagonists↗
PubMed1976

Long term treatment of moderate hypertension with penbutolol (Hoe 893d). II. Effect on the response of plasma catecholamines and plasma renin activity to insulin-induced hypoglycemia.

The effect of insulin-induced hypoglycemia on the blood levels of catecholamines and renin activity has been studied in five patients with moderate hypertension before and after treatment for 3 - 8 months with penbutolol (PEN) 20 - 30 mg twice daily. Penbutolol caused no change in fasting blood glucose level. Insulin o.1 IU per kg body weight i.v. reduced blood glucose concentration by approximately 50 per cent after 30 - 45 min, both before and during treatment with penbutolol. Hypoglycemia prior to medication was accompanied by a marked increase in the production of adrenaline and a minor increase of noradrenaline in all five patients. During treatment the response of adrenaline to hypoglycemia was reduced in four patients and the data was inconclusive in one. Basal renin activity was rather low in three patients, within the normal range in one and relatively high in one. Before penbutolol the hypoglycemia-induced increase in catecholamine production caused no change in plasma renin activity in the three patients with low basal levels, whereas a marked increase was observed in the other two. During medication plasma renin activity remained unchanged on induction of hypoglycemia regardless of the catecholamine response. Despite the marked increase in plasma adrenaline following insulin-induced hypoglycemia, no statistically significant increase in pulse rate was recorded.

Adrenergic beta-Antagonists↗
PubMed1975

The effect of clonidine and penbutolol, respectively on catecholamines in blood and urine, plasma renin activity and urinary aldosterone in hypertensive patients.

In various kinds of hypertension clonidine induced a decrease in urinary catecholamines, plasma renin activity and urinary aldosterone, concommitant with a fall in blood pressure and pulse rate in both short term and chronic studies. Furthermore, clonidine lowered the plasma levels of noradrenaline and adrenaline but a postural increase in upright position still occurred. The capacity to increase renin during salt restriction seemed mainatined. When clonidine was withdrawn all parameters returned to pretreatment levels but in some cases a marked rebound increase in catecholamine production was seen. --During clonidine the increase in catecholamines and renin after insulin induced hypoglycemia was largely abolished. Under basal conditions oral penbutolol induced a decrease of pule rate and blood pressure but no change in plasma or urinary catecholamines. During treatment plasma renin was suppressed at rest and after exercise. A work load, which led to only minor changes in blood catecholamines before treatment, was associated with a marked increase during penbutolol. Medication with penbutolol reduced the response in plasma catecholamines after hypoglycemia and renin activity remained low. Clonidine seems to act mainly by central inhibtion of symapthetic tone. Penbutolol probably acts mainly peripherally but may also have a central effect.

Adrenergic beta-Antagonists↗
PubMed1978

Effects of l-penbutolol (Hoe 893d) on the transmembrane potentials of canine purkinje fibers and ventricular muscle fibers.

Intrinsic membrane effects (non-specific effects) and beta-adrenergic blocking action (specific effects) of l-penbutolol were studied using intracellular microelectrode techniques. l-Penbutolol in concentrations above 0.1 mg/L reduced the maximum rate of depolarization at phase O of both Purkinje fibers and ventricular muscle fibers without affecting their maximum diastolic potential. The action potential duration of Purkinje fibers were also shortened. The shortening of action potential duration and enhancement of automaticity in Purkinje fibers, normally induced by isoproterenol (0.2 mg/L), were antagonized by l-penbutolol in much lower concentraions (0.1--1.0 microgram/L) than those at which nonspecific effects are observed. The difference between these two concentration ranges is sufficient to suggest that l-penbutolol might be a highly specific beta-adrenergic blocking agent.

Action Potentials↗
PubMed1979

A double-blind study of the peripheral vasoconstrictor effects of the beta-blocking drug penbutolol in patients with Raynaud's phenomenon.

A double-blind, placebo-controlled study was carried out in 10 hypertensive patients who were subject to frequent attacks of Raynaud's phenomenon and suffered from cold hands, to assess the peripheral vasoconstrictor effects of penbutolol. After a wash-out period of 2 weeks on placebo, patients received two 14-day treatment periods, in random order, with either 20 mg penbutolol twice daily or placebo separated by a second 2-week single-blind wash-out period on placebo. The results of digital blood flow measurements showed that penbutolol did not produce any additional vasoconstrictor effect on digital circulation. The significance of these findings is discussed.

Adult↗
PubMed1978

The effect on myocardial contractility of a new beta-adrenergic receptor blocking drug, penbutolol.

1 The inotropic effect of penbutolol, a new beta-adrenergic receptor blocking drug, has been compared with that of propranolol in two similar groups of six subjects each. 2 Inotropic changes were assessed from changes in myocardial contractility index [LV dp-dt/11 T] as well as the slope of the regression line relating LV dp/dt to LVED during incremental pacing. 3 Penbutolol was found to have a significant negative inotropic effect of an order similar to that of propranolol in the respective doses studied.

Adult↗
PubMed1977

Beta-2 adrenoceptor blocking activity of penbutolol and propranolol at very low doses.

The relative potency of penbutolol, a new beta adrenergic receptor blocking agent, was compared with propranolol by a four-point assay on healthy male subjects. A dose-response relationship to intravenous doses of propranolol in the microgram range was obtained during a steady state of infusion of epinephrine. Two subjects underwent the entire assay according to the Latin square design and four others each underwent one schedule of design on different days. The potency of penbutolol thus assessed was consistent with reported results. This study emphasizes the importance of intersubject variation and differential receptor sensitivity in individuals. The use of epinephrine as a beta receptor adrenergic agonist for evaluation of selective beta adrenergic receptor blocking activities is discussed.

Adrenergic beta-Antagonists↗
PubMed1977

Penbutolol in hypertension: a pilot study with single daily doses.

A pilot single-blind placebo controlled crossover within-patient study was undertaken in essential hypertension. In ten patients single daily doses of 25 mg and 50 mg and in two patients 25 mg, 50 mg and 100 mg were used. Satisfactory reductions in both systolic and diastolic blood pressure in the supine and erect postures were observed. Reduction in heart rate was of the order of 6-32%, there being no correlation between reductions in blood pressure and decrements in heart rate. Three patients were dropped from the final analyses. Seventy-eight per cent (7/9) of patients had a final diastolic pressure (lying) of 90 mm Hg or less. Single doses of penbutolol controlled blood pressure for at least twenty-four hours. At the end of two weeks on placebo medication, following nine weeks of active drug medication, blood pressure had reverted to near pre-treatment levels. Penbutolol was well tolerated.

Adult↗
PubMed1979

Physico-chemical and anlytical studies of penbutolol.

In the present paper physico-chemical and analytical studies on penbutolol sulfate (Hoe 893d) are reported. In addition to an interpretation of ultraviolet and fluorometric spectra, data are given regarding the dissociation constant, solubility, distribution, and protein binding. The substance and its major metabolte, as well as their glucuronides, are detectable by means of a selective fluormetric method. Moreover, mention is made of the results of a human pharmacokinetic study.

Blood Proteins↗
PubMed1977

Plasma level studies of penbutolol after oral dose in man.

Plasma levels of penbutolol (HOE 893d) were determined in eight healthy adult male subjects after oral administration of 50-mg capsules. Fast absorpiton of the drug from the gastrointestinal tract was indicated by the rapid increase in plasma levels during the absorption phase, with a peak time at about 1 hour after dosing in all subjects. After the peak level, plasma concentrations declined biexponentially, with an average half-life of 2.5 and 27 hours for the fast and slow disposition phases, respectively. These values were in good agreement with data previously found for this drug. Cumulative excretion of intact drug in the urine of the eight subjects during 72 hours after dosing was less than 4 per cent, except for one subject who excreted 9.82 per cent of the dose. Large individual variations were found for area under the plasma level curves, disposition rates, and amounts of intact drug excreted in the urine. Significant pharmacologic effects were noted in all eight subjects at the 50-mg dose level, and mild side effects were evident in one half of these subjects. The average drop in blood pressure and pulse rate for all subjects was 26/18 mm Hg and 19 beats per minute, respectively.

Administration, Oral↗
PubMed1978

Penbutolol, a new non-selective beta-adrenergic blocking compound in the treatment of hypertension. A comparision with propranolol.

The antihypertensive effect of a new non-selective beta-adrenergic blocking compound, penbutolol (40 mg b.i.d.), was compared with propranolol (160 mg b.i.d.) in a series of 20 hypertensive patients using a double-blind cross-over scheme. Both compounds reduced both the supine and the standing blood pressure significantly. The magnitude of the responses did not differ significantly and both compounds evoked a commensurate decrease in heart rate. No significant side-effects were noted and a series of laboratory tests did not disclose any biochemical changes.

Adrenergic beta-Antagonists↗