Mexiletine clearance during peritoneal dialysis.

infant would receive approximately 1.5 mg of disopyramide per day assuming a generous intake of 1 1 of milk. Even taking into account the two fold variability in breast milk levels of disopyramide reported by Barnett et al. (1980), the maximum amount of drug transmitted to the infant would be 3 mg/day (0.6% of the maternal dose). The manufacturer's product information recommends, on the basis of animal data showing concentration of the drug in breast milk of rats, (Karim et al., 1978) that breast feeding be discontinued if the mother is receiving disopyramide. The present data are in general agreement with that of Barnett et al. (1982) in demonstrating that disopyramide is not concentrated in human breast milk and that infants so exposed are unlikely to be adversely affected by the relatively small quantities of drug ingested. However, until further data are gathered it seems prudent to observe these infants closely for adverse effects, particularly those relating to the anticholinergic action of disopyramide and its N-monodesalkyl metabolite in view of the reported increased susceptibility of infants to anticholinergic drugs (Wilson, 1981).