Is generic prescribing acceptable in epilepsy?

Area of Science:

• Pharmacology
• Clinical Pharmacy

Background:

• Generic prescribing for epilepsy is debated, extending beyond cost to include potential toxicity and seizure control.
• Bioavailability and bioequivalence are key considerations, with current measures potentially insufficient for all drug formulations, especially controlled-release types.

Purpose of the Study:

• To evaluate the role and implications of generic prescribing for antiepileptic drugs.
• To examine the bioequivalence of various anticonvulsant formulations and their impact on patient outcomes.

Main Methods:

• Review of existing literature on phenytoin and carbamazepine bioequivalence.
• Analysis of clinical experience and published investigations regarding anticonvulsant drug formulations.

Main Results:

• Extensive literature on phenytoin shows likely bioequivalence issues due to its properties (poor solubility, nonlinear kinetics, narrow therapeutic range).
• Systematic studies on carbamazepine generally indicate no major bioequivalence differences between formulations.
• Limited information exists for other generic anticonvulsant drugs.

Conclusions:

• Tight control over the consistency of both generic and proprietary anticonvulsant drugs is strongly recommended.
• Physician control over prescribing decisions, based on accurate information, is essential for managing epilepsy effectively.