Mexiletine Versus Quinidine as First-Line Antiarrhythmia Therapy: Results From Consecutive Trials

The efficacy of mexiletine and quinidine in controlling ventricular couplets (VC) and ventricular tachycardia (VT) was compared in 156 trials (78 for each drug) in 114 consecutive patients. Forty-two patients received both drugs, whereas 36 patients were given mexiletine, and 36 patients received quinidine only. During acute drug testing, mexiletine was more effective than quinidine in controlling VC and VT (54 vs. 32 patients, respectively, P < .001) and resulted in fewer proarrhythmic events (4 vs. 13, respectively, P < .05). Mean duration of follow-up for mexiletine (27 ± 14 mo) and quinidine (21 ± 14 mo) did not differ. Long-term success was more frequent with mexiletine administration than quinidine administration (33/47 vs. 10/30 patients, respectively, P < .01). The incidence of sudden death during follow-up with the two drugs did not differ overall, but more patients with ejection fraction ≥ 40% died suddenly while taking quinidine than while receiving mexiletine (4/17 vs. 0/24, P < .02). Mexiletine is as effective as quinidine for treating VC and VT and appears to be less proarrhythmic. It should be considered as an initial choice in the management of VC and VT.