Some effects of diphenylhydantoin and propranolol on the cardiovascular system

Acute verapamil poisoning: Successful treatment with epinephrine

“…On the other hand, a direct depressant action of verapamil on sinus node activity (Lupi et al, 1979;Wit and Cranefield, 1974) was probably masked by sympathetic reflex changes triggered by the fall in blood pressure. Hypotension was probably sustained mainly by a marked peripheral vasodilation, but a central mechanism due to a negative inotropic effect cannot be ruled out (Nayler et al, 1968;Singh and Roche, 1977); bradycardia seemed to playa minor role as blood pressure did not change after normalization of cardiac rhythm. Calcium gluconate has been reported to have a favorable therapeutic action and recommended as the treatment of choice in verapamil intoxication (Moroni and Mannaioni, 1980;Perkins, 1978;Woie and Storstein, 1981).…”

Does the administration of the calcium-antagonist verapamil in tocolysis with beta-sympathicomimetics still make sense?

“…They have been demonstrated in numerous well-founded works, in part on isolated preparations and in part on animals äs well äs on sick and healthy people [11,15,16,24,25,26,27]. FLECKENSTEIN [12] revealed the mechanism of the cardiotoxic effect of adrenergics and the possibility of antagonizing this effect with Verapamil (Fig.…”

“…The desired shift of the functional operating curves of the heart and the circulatory effect of Verapamil can only be achieved with doses far higher than those used in tocolysis. In these earlier studies an effect was demonstrated in dogs only after a dose of 200 Mg/kg/min, given äs a single injection, and in humans only after serum concentrations of 200 Mg/ml were reached [11,15,16,24,25], HAAS and RASCHAK [16] also reported that in general extremely high doses of the calcium antagonist are required to obtain the negative inotropic effect. The reason for this is the rapid biotransformation of the active substance Verapamil into ineffective or only weakly effective metabolites [34], Our own studies [38] have revealed that the average serum concentration of the mother after administration of Verapamil at a dosage rate of 2 Mg/kg/min was 19.3 ± 3 ng/ml.…”

The 24-hour ambulatory blood pressure profile with verapamil.

“…Reports conflict in suggesting no change,9' 10 a decrease32' 33 and even an increase in heart rate after treatment.34' " The varying resp nse of the heart rate in different studies may depend on the interaction between direct and reflex effects.…”