A Comprehensive Pharmacological and Clinical Review of Felbinac and Felbinac Trometamol

I. Executive Summary

Felbinac is a non-steroidal anti-inflammatory drug (NSAID) belonging to the arylacetic acid class. It is the principal active metabolite of fenbufen, a prodrug that was withdrawn from several markets due to safety concerns. Felbinac itself has been developed and marketed in two distinct forms, each with a unique therapeutic purpose and risk profile. The first is a range of topical formulations (e.g., gel, foam, patch) used for the localized treatment of musculoskeletal pain and inflammation. The second, and more recent, is felbinac trometamol, a highly water-soluble salt specifically engineered for intravenous (IV) administration to manage moderate-to-severe postoperative pain.

The primary mechanism of action for felbinac is the inhibition of cyclooxygenase (COX) enzymes, thereby reducing the synthesis of prostaglandins that mediate pain and inflammation. While some promotional literature suggests a preference for COX-2, biochemical data indicates it is a largely non-selective inhibitor of both COX-1 and COX-2, a characteristic that carries implications for its safety profile.

The pharmacokinetics of the intravenous formulation, felbinac trometamol, have been well-characterized in clinical trials. It exhibits linear, dose-proportional pharmacokinetics, with predictable plasma concentrations and a half-life of approximately 5-7 hours that supports an every-8-hour dosing regimen for postoperative pain management. In contrast, topical formulations are designed for high local tissue concentration with minimal systemic absorption, which is their key safety advantage.