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At least 19 recordsLinked to original sources
PubMed1979

Bretylium tosylate: a review.

The chemistry, pharmacology, pharmacokinetics, clinical uses, adverse effects, drug interactions and dosage of bretylium tosylate, a recently approved antiarrhythmic agent, are reviewed. Bretylium tosylate is used to treat life-threatening ventricular arrhythmias, principally ventricular fibrillation and ventricular tachycardia, that have not responded to treatment with first-line antiarrhythmic agents. The drug has a direct positive inotropic effect on the myocardium and blocking effect on postganglionic sympathetic nerve transmission. The drug is poorly absorbed orally, requiring either i.m. or i.v. administration. Drug excretion occurs primarily through the kidney, necessitating dosage modification in renal disease. Hypotension is the most commonly observed adverse reaction to bretylium tosylate. Rapid i.v. administration may cause severe nausea and vomiting, and i.m. injection at the same site may cause atrophy and necrosis of muscle tissue. Quinidine and procainamide may potentiate the hypotensive effects of bretylium. Bretylium will aggravate digitalis-induced arrhythmias. Bretylium's use in resistant ventricular tachyarrhythmias requires close clinical monitoring.

Arrhythmias, Cardiac↗
PubMed1976

[Clinical experiences with bretylium tosylate].

Because of its antiarrhythmic and antifibrillatory qualities as well as its positively inotropic effect bretylium tosylate increasingly finds interest. The first results of a clinical and haemodynamical mechanocardiographic investigation with bretylium tosylate are presented. In doses between 1.6 and 6.2 mg/kg body weight intravenously and intramuscularly after an initial increase of blood pressure a clear decrease of the systolic system blood pressure develops. The resistance of the peripheral vessels decreases by 10 to 20%. It is an increase of the heart index and the stroke volume index by 10 to 30% to be proved as an expression of a positively inotropic effect. In orientating investigations the antiarrhythmic effect could be confirmed. The side-effects observed cause us to give a strong indication and to observe the patients carefully. The main area of application of bretylium tosylate might be seen in the possibility to achieve a pharmacological defibrillation of the ventricles.

Adult↗
PubMed1976

[Study of the electrophysiological properties of bretylium tosylate in man].

The electrophysiological changes induced by bretylium tosylate have been studied in 22 patients during the 45 minutes following the intra-atrial injection of the drug at the dose of 5 mg/kg. The potential in the bundle of His was measured, and the stimulus-test method used to determine the refractory period. The results were subjected to Student's test. The sinus rate increased after bretylium. The A-V nodal conduction time (A-H interval) and infra hisian conduction time (HV interval), evaluated at the same imposed frequency, were not affected. The functional refractory period of the A-Vnode was decreased. The relative refractory period of the His-Purkinje system was increased. Finally, the right auricle showed an increase in its effective refractory period, while that of the ventricle remained unchanged. This study suggests that the electrophysiological effects of bretylium are due both to direct action at the cellular level and to sympathetic activity.

Action Potentials↗
PubMed1979

Bretylium tosylate: a newly available antiarrhythmic drug for ventricular arrhythmias.

Bretylium tosylate (Bretylol) has recently been approved for parenteral use against resistant ventricular arrhythmias. The pharmacologic action of bretylium is complex, and its antiarrhythmic action differs significantly from other drugs. Bretylium is an adrenergic neuronal blocking agent taken up selectively at peripheral adrenergic nerve terminals, where it initially releases norepinephrine (sympathomimetic effect) and then produces adrenergic neuronal blockade. It has direct cardiac membrane effect to prolong action potential duration and effective refractory period but, unlike other membrane active antiarrhythmic agents, does not depress conduction velocity or automaticity. Bretylium increases ventricular fibrillation threshold and prevents the decrease in ventricular fibrillation threshold associated with myocardial ischemia. It does not depress myocardial contractility. Clinical studies have shown parenteral bretylium to be effective in suppressing ventricular arrhythmias, particularly recurrent, drug resistant ventricular tachycardia or ventricular fibrillation.

Action Potentials↗
PubMed1977

Experience with bretylium tosylate by a hospital cardiac arrest team.

The effect of bretylium tosylate (BT) was determined in 27 consecutive cases of resistant ventricular fibrillation (VF) encountered by a hospital cardiac arrest team. The VF was sustained and completely resistant to multiple injections of lidocaine, sequential DC shocks at 400 watt-sec and one or a combination of intravenous propranolol, diphenylhydantoin or procainamide. Following 30 min of sustained cardiac massage, BT (5 mg/kg i.v.) was administered. In 20 patients, VF was terminated within 9-12 min after DC shock. Eight of these patients failed to recover while 12 (44%) of all patients resuscitated survived to be discharged from hospital. Eleven out of 20 (55%) of all patients who had a cardiac arrest outside the CCU were survivors; only one out of seven in the CCU were successfully resuscitated. While receiving maintanance BT post-resuscitation (5 mg/kg i.m. q 8-12 hrs x 48 hrs), half the patients developed hypotension and three required vasopressors and/or fluid replacement. The data indicate that BT is a useful agent in patients with sustained VF refractory to repeated lidocaine injections, some other antiarrhythmic agents, and multiple DC shocks.

Bretylium Compounds↗
PubMed1976

Quinidine syncope. A report of successful treatment with bretylium tosylate.

Quinidine syncope is an unpredictable side effect of quinidine administrateion which has a mortality rate of 11.5 per cent when managed with conventional drugs and direct-current countershock. In 2 patients with quindine syncope, the arrhythmias were effectively controlled within 30 minutes following the slow infusion of 150 mg. of bretylium tosylate. This control is contrasted with 2 cases managed in the conventional manner. Bretylium tosylate is a quaternary amine with unique antifibrillatory properties and appears to have a significant role in the management of these arrhylmias.

Adult↗
PubMed1977

Effects of bretylium tosylate on the in vivo fibrillating canine ventricle.

Chemical ventricular defibrillation of the heart by intravenous or intracardiac administration of bretylium tosylate (6 to 24 mg/kg of body weight) did not occur in any dog (n = 30) given the drug 5 minutes before, immediately after, or 75 seconds after electrical induction of ventricular fibrillation. The bretylium did not appear to stabilize ventricular irritability nor facilitate resuscitation by electrical defribrillation when compared with the control group of dogs. Significant dose-dependent chronotropic or systemic pressure effects were not seen following bretylium administration.

Animals↗
PubMed1976

[Bretylium tosylate as an anti-arrhythmic drug].

With the help of an analysis of the world literature pharmacological, pharmacokinetic and electrophysiological properties as well as the possibilities of the clinico-therapeutic use of Bretylium tosylat are demonstrated. The pharmacon is of increasing interest as antiarrhytmic, especially in the commandment of otherwise therapy-refractory ventricular disturbances of rhythm. A positively inotropic effect is proved. More severe side effects, such as arterial hypotension and increase of the pulmonary vascular resistance have an objection to routine application. The antifibrillatory effect needs particular consideration. This effect might promote this pharmacon to the "chemical defibrillator" in the emergency situation.

Animals↗
PubMed1976

Effect of adrenergic neuron inhibitors on the vascular response to sympathetic nerve stimulation.

In anesthetized cats, the lumbar sympathetic trunk was stimulated, and the responses of the resistance and capacitance vessels of the hindlimb were recorded (by resistography and plethysmography, respectively). The drugs used were reserpine, methyldopa and bretylium tosylate. It was found that reserpine and methyldopa inhibit the response of the resistance vessels to a greater extent than that of the capacitance vessels, while bretylium tosylate has a greater effect on the transmission of constrictor impulses to the capacitance vessels. Reserpine mainly suppresses responses to low-frequency stimulation and bretylium tosylate--those to high-frequency stimulation, while methyldopa affects them to the same degree at all frequencies.

Animals↗
PubMed1978

Porcine malignant hyperthermia. VI: the effects of bilateral adrenalectomy and pretreatment with bretylium on the halothane-induced response.

The effects of bilateral adrenalectomy, together with the i.v. administration of bretylium tosylate 20 mg kg-1 on halothane-induced malignant hyperthermia (MH), were investigated in six Pietrain pigs. All six animals survived the halothane challenge, and failed to show any signs of increased muscle metabolism. Bilateral adrenalectomy alone prevented halothane-induced MH in three out of four Pietrain pigs, whereas the i.v. administration of bretylium alone protected only one pig out of an additional four animals studied. The results show that complete adrenergic blockade inhibits the susceptibility of Pietrain skeletal muscle to halothane and that the adrenal medulla makes an important contribution to this response.

Adrenalectomy↗
PubMed1977

GI drug absorption in rats exposed to cobalt-60 gamma-radiation I: Extent of absorption.

The extent of absorption of sulfanilamide, bretylium tosylate, sulfisoxazole acetyl, and riboflavin was determined in rats exposed to 850 rad of cobalt-60 gamma-radiation of sham irradiated. The drug were administered orally at 1 or 5 days postirradiation, and the amount of drug excreted in the urine was used as the measure of absorption. Following intravenous drug administration, there was no difference between irradiated and control animals in the amount of drug excreted in the urine. At 1 day postirradiation, the absorption of sulfanilamide and bretylium was not affected by radiation; the absorption of sulfisoxazole acetyl and riboflavin was increased. The fraction of sulfanilamide excreted in the urine as N4-conjugate was increased at 1 day postirradiation. At 5 days postirradiation, there was no detectable difference between irradiated and control animals in the extent of drug absorption. The effects of radiation on the extent of absorption of orally administered drugs were most pronounced immediately following irradiation. Irradiation apparently does not affect the absorption of drugs that are normally well absorbed or poorly absorbed due to slow transport across the GI mucosa. Following irradiation, there may be an increase in the extent of absorption of drugs that are poorly absorbed due to low aqueous solubility or that are absorbed by a saturable transport mechanism.

Animals↗