Drug interactions with Ethmozine (moricizine HCl)

Moricizine HCl, a phenothiazine derivative synthesized in the USSR in 1964, has been shown to be an orally effective antiarrhythmic drug. Moricizine HCl has demonstrated a low incidence of generally mild and transient side effects. Studies of possible drug interaction between it and other drugs most likely to be administered to cardiovascular patients are currently being conducted in US drug trials. Possible interactions between moricizine HCl and cimetidine, and between moricizine HCl and digoxin, are reviewed. The coadministration of moricizine HCl had no effect on the pharmacokinetics of cimetidine; in contrast, cimetidine administration slowed the elimination of moricizine HCl. The implications of greater therapeutic and/or toxic effects of moricizine HCl must be considered for patients receiving cimetidine and moricizine HCl concomitantly. No significant interactions were observed when monitoring serum levels of moricizine HCl and digoxin in patients with normal renal function receiving digoxin therapy for congestive heart failure or atrial fibrillation. Moricizine HCl in therapeutic dosages (10 mg/kg daily) demonstrated antiarrhythmic efficacy without significant alterations in serum digoxin levels.