Verapamil

The dose of verapamil must be individualized by titration. The usefulness and safety of dosages exceeding 480 mg/day have not been established; therefore, this daily dosage should not be exceeded. Since the half-life of verapamil increases during chronic dosing, maximum response may be delayed. Angina: Clinical trials show that the usual dose is 80 mg to 120 mg three times a day. However, 40 mg three times a day may be warranted in patients who may have an increased response to verapamil (e.g., decreased hepatic function, elderly, etc.). Upward titration should be based on therapeutic efficacy and safety evaluated approximately eight hours after dosing. Dosage may be increased at daily (e.g., patients with unstable angina) or weekly intervals until optimum clinical response is obtained. Arrhythmias: The dosage in digitalized patients with chronic atrial fibrillation (see PRECAUTIONS ) ranges from 240 to 320 mg/day in divided (three times a day or four times a day) doses. The dosage for prophylaxis of PSVT (non-digitalized patients) ranges from 240 to 480 mg/day in divided (three times a day or four times a day) doses.