Mexilitene use in pregnancy.

Mexilitene, a class 1b antiarrhythmic, was used throughout an entire pregnancy to treat symptomatic premature ventricular contractions in a patient with mitral valve prolapse. Cord blood and maternal serum mexilitene levels at the time of delivery are given. The following conclusions were reached. (1) Mexilitene may have a future in treating pregnant patients with arrhythmias unresponsive to currently approved antiarrhythmic drugs. (2) Evidence to date has shown no adverse affects in infants of mothers breast-feeding while taking mexilitene. (3) Dosages need to be monitored carefully during pregnancy and the postpartum period to ensure that therapeutic drug levels are maintained.