Comparable steady-state bioavailability between two preparations of conventional-release procainamide hydrochloride

Area of Science:

• Pharmacology
• Clinical Pharmacy
• Drug Bioavailability

Background:

• Pharmacy and therapeutics committees play a role in evaluating drug effectiveness and cost.
• Restrictive formulary systems benefit from clinical evaluations.
• Procainamide hydrochloride (PA) is used for ventricular dysrhythmias.

Purpose of the Study:

• To evaluate the economic and functional effectiveness of a generic procainamide hydrochloride (PA) formulation.
• To compare the serum-concentration profiles of two PA preparations (Squibb vs. Ascot).

Main Methods:

• Randomized, single-blind, crossover study design.
• Evaluation of ten outpatients on chronic PA therapy.
• Comparison of serum PA concentrations, area under the curve, peak concentrations, and peak-trough fluctuations.

Main Results:

• No significant differences in dose-adjusted serum PA concentrations between Squibb and Ascot formulations.
• Relative bioavailability of generic PA was 0.972 +/- 0.59.
• Ascot PA showed a 15-minute delay in absorption onset but an earlier Tmax.

Conclusions:

• Generic procainamide hydrochloride (PA) is bioequivalent to the brand-name formulation.
• Generic substitution of PA can lead to substantial cost savings.
• The findings support the use of generic PA in formulary systems.