Cibenzoline

Comparative studies

Cibenzoline and flecainide have been compared in the prevention of recurrence of atrial tachydysrhythmias in 139 patients [ ]. During the study, 27 patients withdrew, in 13 cases with adverse effects, seven of which were due to cibenzoline. Overall there were 26 adverse effects in 23% of the patients taking cibenzoline; these included one case of ventricular dysrhythmia, four minor cardiac events, four cases of nausea or epigastric pain, eight cases of weakness, four cases of depression or insomnia, one rash, and one case of hypoglycemia. The QRS complex was prolonged by more than 13% in 14 patients, but the QT interval was not prolonged. Although this was not a placebo-controlled study, the incidence of adverse effects with cibenzoline was probably as one would expect in such a population.

Cardiovascular

Cibenzoline prolongs the PR interval, the QRS interval, and the QT _c interval [ ]. It also prolongs the AH and HV intervals [ , ] and shortens the sinus cycle length [ ]. Because of these effects it can cause dysrhythmias [ , , , ].

• Cardiac dysrhythmias have been attributed to cibenzoline in a 60-year-old man with hypertrophic cardiomyopathy [ ].

• In a 72-year-old woman cibenzoline was associated with left bundle branch block and heart failure [ ]. Excess cibenzoline accumulation was suspected, because of reduced renal function, but plasma cibenzoline concentrations were not reported.

Right bundle branch block has also been reported [ ].

In three patients in whom cibenzoline had caused sinus node dysfunction, normal sinus node recovery time was restored by cilostazol [ ].

Cibenzoline has a negative inotropic effect and can therefore cause hypotension [ , , , ] and worsening heart failure [ ].

Cibenzoline has been reported to have unmasked Brugada syndrome in a 61-year-old woman [ ]. Ajmaline reproduced the effect. The authors concluded that cibenzoline should probably be avoided in patients with Brugada syndrome.