TOCAINIDE

Fetal Risk Summary

Tocainide is indicated for the treatment of ventricular arrhythmias but has also been used in the treatment of myotonic dystrophy and trigeminal neuralgia.

In mice, tocainide and its metabolites cross the placenta to the fetus (TP Dowling, personal communication, Merck Sharpe & Dohme, 1987). The drug was not teratogenic in rats and rabbits exposed to doses up to 4 and 12 times the usual human dose, respectively (1). These doses were maternotoxic in both species. At maternotoxic doses 8–12 times the usual human dose in rats, dystocia, delayed parturition, an increased incidence of stillbirth, and reduced survival of the offspring in the first week after birth were noted (1). No reports describing the use of tocainide in human pregnancy have been located.

Breast Feeding Summary

No reports describing the use of tocainide during lactation have been located. The low molecular weight (about 229), however, is low enough that passage into milk should be anticipated. The effect of this exposure on a nursing infant is unknown.

Reference