Acebutolol in hypertension--double-blind trial against placebo.
(25/69)
1. Eleven hypertensive patients were studied in a double-blind comparison of acebutolol, a beta-adrenoceptor blocker, and placebo. 2. Optimum dosage defined in an open assessment varied from 200--600 mg twice daily. 3. Blood pressure and pulse rate fell significantly while patients were lying, standing and after exercise. 4. Blood pressure remained as well controlled on each patient's optimum daily dose when taken once daily, and assessed 24 h post dose. 5. There was no correlation between blood pressure reduction and changes in heart rate. On once daily therapy while blood pressure remained unchanged at 24 h post dose there was a signficant reduction in beta-adrenoceptor blockade as measured by percentage reduction in exercise tachycardia. 6. There was no significant change in urinary catecholamine excretion or echocardiographically estimated cardiac output. 7. A correlation was found between the change in plasma renin activity (log transformed) and blood pressure reduction. (+info)
Onset and duration of beta-adrenergic receptor blockade following single oral dose acebutolol hydrochloride (Sectral).
(26/69)
1. The onset and duration of action of once daily acebutolol (400 mg) on resting and exercise heart rate and blood pressure were studied in normal subjects in a double-blind, cross-over trial against placebo. Subjects were studied 1.5, 3, 8 and 24 h after the first dose and 24 h after the fifth dose. 2. Resting and exercise heart rate and blood pressure were significantly reduced within 90 min of the first dose. 3. A significant reduction in these variables persisted throughout 24 h after the fifth daily dose. However, at 24 h the effects were considerably attenuated, the falls in resting and exercise systolic blood pressure being only 5%. 4. A linear relationship was noted between log serum drug level and percentage reduction of exercise heart rate. (+info)
Acebutolol and oral surgery: plasma levels following a single oral dose.
(27/69)
Twenty eight patients were randomly allocated into treatment or placebo groups. The treatment group received a single 400 mg oral dose of acebutolol, the placebo group an identical inert prepation. A blood sample from each patient was subsequently analysed for plasma concentrations of acebutolol and diacetolol, and the electrocardiogram was continuously monitored for changes of rate and rhythm. The plasma concentrations of acebutolol and diacetolol were all above the previously reported minimum levels for effective dysrhythmia control and the nine patients in whom irregularities of rhythm occurred were all in the placebo group. One patient in the treatment group, who was 58 years old, required intravenous injection of atropine for bradycardia and hypotension after induction of anaesthesia. It is suggested that in patients with small body weights and in those patients over 50 years of age the predmedication dose of acebutolol should be reduced to 200 mg. (+info)
Reduction of early ventricular arrhythmia by acebutolol in patients with acute myocardial infarction.
(28/69)
To assess the effects of intravenously administered acebutolol (1-20 mg every 4 hours for 24 hours) on cardiac rhythm and performance, we studied 72 patients with evolving myocardial infarction. Twenty-five patients were treated with acebutolol beginning 6 hours after the first increase in the level of plasma creatine kinase. Enzymatically estimated infarct size was compared with that of 25 controls matched for predicted infarct size. Observed infarct sizes were not significantly different in the 2 groups (37 +/- 5 and 30 +/- 5 CK-gram equivalents, respectively). Mean heart rate, diastolic blood pressure, and cardiac output declined from control values during treatment with acebutolol, but remained within the normal range. Mean pulmonary artery pressure and pulmonary artery occlusive pressure were unchanged. In a group of 22 treated patients matched with 22 control subjects for frequency of ventricular extrasystoles, acebutolol effected a prompt reduction in frequencies of ventricular extrasystoles and repetitive arrhythmias, whereas values were not significantly changed in controls during the corresponding intervals. Accordingly, acebutolol may be a useful antiarrhythmic agent in selected patients with acute myocardial infarction with adversely altering haemodynamic stability or enzymatically estimated infarct size. (+info)
Haemodynamic effects of acute beta-adrenergic receptor blockade in congestive cardiomyopathy.
(29/69)
Acebutolol ('Sectral'), a cardioselective beta-blocking drug, was administered intravenously in a dose of 25 mg to 10 patients with congestive cardiomyopathy. All of them were in a stable condition on antifailure regimens. The drug resulted in a statistically significant decline in left ventricular contractility as judged by peak left ventricular dP/dT and the contractility index. The mean aortic blood pressure also fell. There was a significant increase in end-diastolic and end-systolic left ventricular volumes. Mean values for heart rate, ejection fraction, left ventricular stroke work index, and cardiac output also fell, but the results were not statistically significant. Left ventricular distensibility as judged by the slope of the diastolic pressure-volume relation also improved significantly. A reduction in myocardial energy requirements, improved compliance, and lowering of arterial pressure would be haemodynamically advantageous. However, further cardiac dilatation and reduction contractility--the basic defects in congestive cardiomyopathy--could lead to further deterioration. (+info)
Noradrenaline producing phaeochromocytomas with absent pressor response to beta-blockade.
(30/69)
In 2 patients with phaeochromocytoma, effective beta-blockade was obtained with propranolol (40 mg twice a day for 3 days) or acebutolol (400 mg twice a day for 3 days) without any effect on the blood pressure. In both patients the excretion of noradrenaline predominated over that of adrenaline, a picture found in most cases of phaeochromocytoma. A hypertensive response to beta-blockade might be expected in patients with an adrenaline-secreting tumour. It cannot be a regular event or constitute a diagnostic test in patients with suspected phaeochromocytoma. (+info)
A comparison of the bronchoconstrictor and beta-adrenoceptor blocking activity of propranolol and acebutolol.
(31/69)
The bronchoconstrictor and beta-adrenoceptor blocking activity of (+/-)-propranolol, acebutolol and two of its analogues were compared in a group of littermate rats. Whilst the analogues of acebutolol had similar bronchoconstrictor potency to propranolol, acebutolol had considerably less activity. No correlation could be found between the degree of bronchoconstriction produced by the four drugs and their beta-adrenoceptor blocking activity in the airway smooth muscle. Acebutolol and its analogues show a wide properties could be related to the production of bronchospasm. (+info)
Acebutolol, metoprolol and propranolol in conscious dogs with chronic heart-block: chronotropic effects and relation between depression of ventricular activity and beta-adrenoceptor blocking potency.
(32/69)
1 Atrial and ventricular chronotropic effects of acebutolol, metoprolol and propranolol were studied in conscious dogs with chronic heart-block. Ventricular beta-adrenoceptor blocking activity was assessed for the three dogs against isoprenaline (1 microgram/kg) under the same experimental conditions. 2 Acebutolol and metoprolol significantly increased atrial rate. The effect was proportional to the dose for acebutolol, independent for metoprolol. Propranolol had no significant effect on atrial rate. All three drugs significantly lowered ventricular rate in proportion to the dose. 3 Ventricular beta-blocking potencies of metoprolol and acebutolol were respectively 2 and 3 times weaker than that of propranolol as indicated by ED50 values. 4 The ventricular depressor effect observed was proportional to the degree of ventricular beta-blockade present, although this may not be the only factor involved. (+info)