[Diaplacental transfer of verapamil in guinea pigs (author's transl)]

Verapamil (1--50 mcg/kg/min) was given to guinea pigs by intravenous infusion for 30 minutes. The average clinical dosage amounts to 1 (0,5--2) mcg/kg/min. At doses of 1--10 mcg/kg/min we could not find pharmacologically effective concentrations of verapamil in plasma, although concentrations in mother rose corresponding to administered doses. Only at dosage 50 mcg/kg/min we found comparatively to the mother low, but clearly measurable concentrations also in fetal plasma. That means: Verapamil, administered to guinea pigs--hemomonochorial placentation like man--in dosage, given for tocolysis does not appear in fetal plasma with pharmacologically effective concentration.