The effect of beta-adrenoceptor antagonists alone and in combination with a GABA-elevating agent on isoniazid-induced convulsions in rats.

A delay in the onset of isoniazid-induced convulsions was found in rats pretreated with the beta 2-adrenoceptor blocker, butoxamine and the nonspecific beta-blocker, propranolol. In these animals the convulsive responses were inhibited in a dose dependent manner. These compounds were found to be effective even after the induction of convulsions. The beta 1-blocker, acebutolol was able to protect rats only when injected prior to the challenge. The anticonvulsant effect of acebutolol and propranolol but not that of butoxamine was found to be enhanced in animals pretreated with a gamma-aminobutyric acid (GABA) elevating agent, aminooxyacetic acid (AOAA). The findings indicate that the GABA-mediated anticonvulsant action of AOAA seems to be additive with that resulting from beta 1 but not beta 2-blockade.

Membrane stabilizing action of cardio-selective Beta-adrenergic blocking agent [acebutolol] on the electrically stimulated diaphragmatic tissue of the rat

Isolated diaphragm of albino rats was prepared and effect of electric stimulation was observed before and after treatment of the tissue with the cardioselective beta-adrenergic blocking agent, acebutolol. Acebutolol did not produce no Significant effect on the response of tissue to electric stimulation in small doses. But in high dose, there was marked pression of the contractile effect of tissue to electric stimulation. It is concluded that this effect of acebutolol in high uses is due to the membrane stabilizing action of the drug

Respuesta tensional al ejercicio dinámico e isométrico en hipertensos tratados con labetolol o acebutolol / Arterial pressure response to dynamic exercise in hypertensives treated with labetalol or acebutolol

En el presente estudio de diseño simple-ciego, placebo-control, cruzado y randomizado, evaluamos la respuesta tensional y las modificaciones hemodinámicas causadas por el tratamiento oral y durante dos semanas con un agente bloqueador beta-adrenérgico selectivo con efecto simpático-mimético intríseco (Acebutolol, 400 mg/día) o con un agente bloqueador alfa y beta-adrenérgico (Labetalol, 400 mg/día). A tal efecto, 25 pacientes hipertensos leves fueron sometidos a ejercicio isométrico al 30% de su capacidad máxima y a ejercicio dinámico hasta un máximo de 75W, bajo monitoreo con electrograma de impedancia y durante ciclos de tratamiento con placebo, Acebutolol o Labetalol en forma cruzada, La efectividad terapéutica de ambas drogas fue similar en reposo, pero el Labetalol indujo una menor respuesta hipertensiva al ejercicio isométrico que el Acebutolol, la cual parece deberse a un menor incremento de las resistencias periféricas. Durante el ejercicio dinámico se observó una atención de la respuesta hipertensiva similar con ambos medicamentos; el labetalol, sin embargo, permitió un incremento del gasto cardíaco mayor que el tratamiento con Acebutolol. Estos efectos diferenciales del Labetalol se atribuyen a su efecto bloqueador alfa-adrenérgico, y lo hacen particularmente útil en pacientes hipertensos con actividad física moderada o intensa

Antihypertensive effect of nifedipine-retard and acebutolol in patients with hypertension: a randomized double-blind study

A randomized double-blind, comparative study, with a new slow release preparation of nifedipine (nifedipine-retard), was undertaken in patients with mild, moderate and severe essential hypertensión WHO (stage I-II). After a two-week placebo period, patients were divided into three groups: 1) group I received nifedipine-retard 20 mg orally twice daily; 2) group II received acebutolol 200 mg orally twice daily; and 3) group III received nifedipine-retard 20 mg once daily plus acebutolol 200 mg orally once daily. All three dosage regimens were administered for six weeks. Nifedipine-retard (group I) reduced supine blood pressure from 162 ñ 4.2/105 ñ 1.4 mmHg (21.6 ñ 0.5/14.0 ñ 0.2 Pa) to 139 ñ 4.2/92 ñ 2.6 mmHg (18.5 ñ 0.5/12.3 ñ 0.3 kPa) and slighrly increased the heart rate. Acebutolol (group I) reduced supine blood pressure from 163 ñ 5.3/107 ñ 2.8 mmHg (21.7-0.7/14.2 ñ 0.4 kPa) to 144 ñ 5.0/93 ñ 3.7 mmHg (192 ñ 0.7/12.4 ñ 0.5 kPa) and decreased the heart rate. Nifedipine retard plus acebutolol (group III) reduced supine blood presure from 144 ñ 3.0/101 ñ 1.3 mmHg (19.2 ñ 0.4/13.4 ñ 012 kPa) to 123 ñ 3.4/84 ñ 2.8 mmHg (16.4 ñ 0.5/11.2 ñ 0.4 kPa) and did not significantly alter the heart the heart rate. There was a significant correlation (r = 0.65, p < 0.03) betwee baseline blood pressure and diastolic blood pressure after six weeks of therapy nifedipine-retard. There was a no significant trend between the age of patients and decrease of diastolic blood pressure, positive for nifedipine-retard, and negative for acebutolol. There was a low incidence of side effects with all dosage regimens..