Activity of Procanbid, procainamide twice-daily formulation, to suppress ventricular premature depolarizations. The Study Group Investigators.
Procainamide is a class IA antiarrhythmic drug indicated for the treatment of life-threatening or symptomatic ventricular arrhythmias. The current sustained-release formulation requires 6-hour dosing (qid). To improve patient compliance, a new sustained-release formulation for twice-daily (bid) administration has been developed (Procanbid, Parke-Davis). This study assesses the pharmacologic equivalence of the bid and qid formulations in the suppression of symptomatic ventricular premature depolarizations (VPDs). Fourteen centers enrolled a total of 99 patients with frequent symptomatic VPDs (average > or = 20 VPDs/hr) who previously responded to and tolerated the procainamide qid formulation. During the first week of the double-blind phase, patients were randomized to either placebo or procainamide dosages of 1000, 2000, or 4000 mg/d (bid or qid formulations). In the second week, the patients were crossed over to the alternate formulation. Seventy-seven patients qualified for the primary activity analysis. The bid and qid formulations showed comparable effectiveness in the suppression of mean VPDs with a linear dose-response relationship. The VPD suppression was not attenuated towards the end of the dosing interval for either formulation. Sixty-eight of these patients entered an optional 1-year extension to receive the bid formulation. Thirty-seven (54%) patients had adverse effects. Of those, 15 (22%) had side effects considered treatment related. Most of the adverse events occurred during the first 6 weeks of treatment. Only a few patients (8%) withdrew as a consequence of treatment with the bid formulation. The overall safety profile of the bid formulation was similar to other formulations, and the procainamide bid formulation has a low proarrhythmic rate (< 3%). In conclusion, the effectiveness of the twice-daily formulation of procainamide in the suppression of VPDs is comparable to the currently available qid formulation.
Kerin
N Z
NZ
Sinai Hospital, Detroit, Michigan, USA.
Meengs
W L
WL
Timmis
G C
GC
Salerno
D
D
Haber
H E
HE
Singer
R M
RM
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects / Q000627:therapeutic use*; D018592:Cross-Over Studies; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D011342:Procainamide / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use*; D018879:Ventricular Premature Complexes / Q000188:drug therapy* / Q000503:physiopathology
D000889:Anti-Arrhythmia Agents; D003692:Delayed-Action Preparations; D011342:Procainamide