Procaineamide blood levels after administration of a sustained-release preparation.

Procaineamide is now available as a sustained-release preparation. This preparation was administered in an eight-hourly regime to 26 patients, and therapeutic blood levels were obtained for the duration of the 56-hour study period in 20 patients. No side effects were observed. Inadequate blood levels may be predicted from a single blood level eight hours after the first dose, which could allow for dosage adjustment.