[Combination of oral administration of cibenzoline and digoxin in patients with supraventricular arrhythmia]

Chronic co-administration of digoxin and several antiarrhythmic drugs increases digoxin plasma levels. To determine the effects of the administration of oral cibenzoline on digoxin plasma levels and its effects on clinical and electrocardiographic parameters, we conducted a prospective multicenter study in 22 cardiac patients with a mean age of 66 +/- 12 years (39-85), who were on long term digoxin therapy (0.25 mg once daily for at least 2 weeks) and who required oral cibenzoline therapy in the prevention of recurrence of symptomatic atrial tachyarrhythmias. Cibenzoline was given for 4 weeks at a dose of 130 mg twice daily in patients aged less than 70 years (group I, n = 15) and this dosage was reduced by half in patients over 70 years of age (group II, n = 7). Evaluation of the effects of this combination on clinical and electrocardiographic tolerability as well as the drawing of blood samples for assay of cibenzoline and digoxin took place before and after 4 weeks treatment with cibenzoline. The digoxin plasma levels were (mean +/- sem) 0.96 +/- 0.1 ng.ml-1 before cibenzoline administration and remained unchanged after 4 weeks of combination therapy (1.0 +/- 0.1 ng.ml-1), p > 0.05. Digoxin plasma levels in group I varied from respectively 0.8 +/- 0.1 ng.ml-1 (0.5-1.7) to 0.8 +/- 0.1 ng.ml-1 (0.4-1.5) and in group II from 1.2 +/- 0.2 ng.ml-1 (0.6-2) to 1.4 +/- 0.3 ng.ml-1 (0.7-2.5). This therapy was well tolerated in 16 patients out of 21 evaluable patients (76%) and there was no significant change in vital signs during the study.(ABSTRACT TRUNCATED AT 250 WORDS)