Tocainide: a new oral antiarrhythmic agent.

Tocainide, a newly released class 1B antiarrhythmic agent, has membrane stabilizing and electrophysiologic characteristics similar to those of lidocaine, but it can be prescribed for oral administration. Investigational studies in both animals and humans have shown tocainide's effectiveness for the treatment of ventricular arrhythmias in chronic and acute settings. The drug has nearly 100% bioavailability after oral administration and an effective half-life of 9 to 37 hours (mean, 15 hours). Antiarrhythmic efficacy is similar to that of other class I medications currently in use. Serious side effects most frequently involve the central nervous or gastrointestinal system and occur in 10% to 20% of patients. Tocainide has minimal negative inotropic effects and a tendency to shorten effective refractory periods.