title: Low dose quinidine-mexiletine combination therapy versus quinidine monotherapy for treatment of ventricular arrhythmias.
abstract: Low dose quinidine-mexiletine combination therapy was compared with quinidine monotherapy in 15 patients with frequent ventricular premature complexes and nonsustained ventricular tachycardia in a dose escalation cross-over study. Oral combination therapy was initiated with quinidine gluconate (165 mg) plus mexiletine (150 mg) every 8 h. If ventricular premature complexes were not suppressed greater than or equal to 80% and nonsustained ventricular tachycardia greater than or equal to 90%, the dose was increased to a maximum of 330 mg of quinidine plus 200 mg of mexiletine. Quinidine monotherapy was initiated with 330 mg and escalated to a maximum of 660 mg every 8 h if criteria for effectiveness were not met. Combination quinidine-mexiletine therapy suppressed 80% of ventricular premature complexes in 13 of 14 patients and suppressed 100% of episodes of ventricular tachycardia in 6 of 8 patients (mean quinidine dose 200 +/- 70 mg; mean mexiletine dose 146 +/- 24 mg every 8 h). The mean effective trough quinidine and mexiletine concentration was 1.0 +/- 0.7 and 0.9 +/- 0.4 microgram/ml, respectively. Monotherapy was less effective; that is, greater than or equal to 80% suppression of ventricular premature complexes was observed in 5 of 15 patients and 100% suppression of ventricular tachycardia in 2 of 9 patients. The mean quinidine monotherapy dose was 462 +/- 155 mg every 8 h; the mean quinidine concentration was 1.8 +/- 0.8 microgram/ml. Adverse systemic effects occurred in 3 patients on quinidine-mexiletine therapy and in 11 on quinidine monotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, College of Physicians & Surgeons, Columbia University, New York, New York 10032.
authors.forename: E G
authors.initials: EG
authors.lastname: Giardina
authors.forename: M E
authors.initials: ME
authors.lastname: Wechsler
mesh_terms: D001145:Arrhythmias, Cardiac / Q000188:drug therapy*; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D015716:Electrocardiography, Ambulatory; D005260:Female; D006801:Humans; D008297:Male; D008801:Mexiletine / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D011802:Quinidine / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D016037:Single-Blind Method; D013318:Stroke Volume
chemical_list: D008801:Mexiletine; D011802:Quinidine