Pharmacokinetic interactions between eperisone hydrochloride and aceclofenac: a randomized, open-label, crossover study of healthy Korean men.

Background: Eperisone hydrochloride, a centrally acting muscle relaxant, is a calcium antagonist that causes vasodilation and antispastic actions. Aceclofenac, an anti-inflammatory analgesic and antipyretic drug, has similar efficacy and improved gastrointestinal tolerance compared with other nonsteroidal anti-inflammatory drugs, such as diclofenac. Although eperisone hydrochloride and aceclofenac are frequently coadministered, no published studies have reported on the pharmacokinetic interactions between these 2 drugs.

Objective: The aim of this study was to investigate any pharmacokinetic interactions between eperisone hydrochloride and aceclofenac in healthy Korean men.

Methods: This was a randomized, open-label, crossover study. Each participant was randomly assigned to 1 of 6 treatment sequences and received eperisone hydrochloride (3 doses of 50 mg each), aceclofenac (2 doses of 100 mg each), or both as a single dose with a 7-day washout period between each dose. Blood samples were collected ≤ 24 hours after dosing, and plasma eperisone hydrochloride and aceclofenac concentrations were determined using validated LC/MS-MS. Pharmacokinetic analyses were conducted using noncompartmental methods. A safety profile was determined using the measurement of vital signs, ECG, and clinical laboratory tests.

Results: A total 24 of men were enrolled, and all completed the study. The geometric mean ratios (90% CIs) of the Cmax and AUC0-∞ values for eperisone were 1.18 (0.828-1.673) and 1.12 (0.836-1.507), respectively. The geometric mean ratios (90% CIs) of the Cmax and AUC0-∞ for aceclofenac were 0.93 (0.847-1.022) and 1.01 (0.979-1.036), respectively. A total of 7 adverse events were reported in 7 men. All adverse events were mild, and no significant differences were found between treatment groups.

Conclusion: No clinically significant pharmacokinetic differences exist between 150 mg eperisone hydrochloride and 200 mg aceclofenac when administrated as a monotherapy or in combination.