Verapamil and norverapamil in plasma and breast milk during breast feeding

Summary The concentrations of verapamil and norverapamil have been measured in milk and plasma samples from a 32year-old woman treated with verapamil 80 mg tds while breast-feeding her child.The average steady-state concentrations of verapamil and norverapamil in milk were, respectively, 60% and 16% of the concentrations in plasma.The breast-fed child received less than 0.01% of the dose of verapamil given to the mother. No verapamil or norverapamil (<1 ng/ml) could be detected in the plasma from the child.