Effect of the gastrointestinal prokinetic agent erythromycin on the pharmacokinetics of pregabalin controlled-release in healthy individuals: a phase I, randomized crossover trial.

Background And Objectives: The controlled-release (CR) formulation of pregabalin is designed to remain in the stomach for a prolonged period while slowly releasing pregabalin for absorption in the small intestine. This study evaluated the effect of the gastrointestinal prokinetic agent, erythromycin, on the pharmacokinetics of a single dose of pregabalin CR 330 mg administered following an evening meal and the safety and tolerability of a single dose of pregabalin CR 330 mg when administered with and without multiple doses of erythromycin 500 mg.

Methods: This was a phase I, open-label, randomized, two-period, two-treatment crossover study. Participants received (in a randomized sequence) a single oral dose of pregabalin CR 330 mg alone and pregabalin CR 330 mg co-administered with multiple doses of erythromycin 500 mg. The CR formulation was administered immediately following a standardized 600-750 calorie 30 % fat evening meal. Erythromycin 500 mg was administered orally approximately 1 h prior to pregabalin CR, as well as 6 and 12 h following the first erythromycin dose. Blood samples were collected up to 48 h post-pregabalin CR dose. Pharmacokinetic parameters were estimated from concentration-time data using standard noncompartmental methods. Adverse events were monitored throughout.

Results: Eighteen healthy participants (aged 19-52 years) received pregabalin CR. Co-administration of pregabalin CR with erythromycin resulted in a 17 % decrease in total exposure [area under the plasma concentration-time curve from zero to infinity (AUC∞)] and a 13 % decrease in peak plasma concentrations (C max) relative to pregabalin CR administered alone. The 90 % CI for the ratio of the adjusted geometric mean AUC∞ was 76.5-89.2 % (outside the 80-125 % range prespecified for bioequivalence). Adverse events were of mild to moderate severity and the adverse event profile was similar for pregabalin CR administered with and without erythromycin.

Conclusion: Co-administration of multiple high doses of erythromycin resulted in 17 % lower pregabalin exposure for a single dose of pregabalin CR 330 mg than for pregabalin CR 330 mg administered alone. Although the two treatments did not achieve formal bioequivalence, the impact of co-administered erythromycin treatment was small and not considered clinically relevant.