OBJECTIVE
To evaluate the effect of the antioxidant ethylmethylhydroxypyridine succinate (EMHPS) on the analgesic effects of cyclooxygenase (COX) inhibitors in a model of postoperative hyperalgesia in rats.
MATERIAL AND METHODS
Mechanical (von Frey test) hyperalgesia in the surgical suture area and metatarsus of rats was recorded for 4 days after surgery (longitudinal incisions of the skin and the flexor digitorum brevis muscle of the hind paw). A non-selective inhibitor of COX diclofenac sodium at a dose of 1 mg/kg and 10 mg/kg, followed by a dose reduction to 5 mg/kg due to the toxic effect of the drug, a selective inhibitor of COX-2 etoricoxib at a dose of 1 mg/kg and 10 mg/kg, EMHPS at a dose of 25 mg/kg administered orally twice a day, starting from the day of the surgery and for 3 days afterwards.
RESULTS
Etoricoxib at a dose of 10 mg/kg, but not at a dose of 1 mg/kg, reduced the postoperative hyperalgesia in the metatarsus on days 1, 2 and 3 after the surgery, and did not affect significantly the pain response in the surgical suture area. Diclofenac sodium and EMGPS did not have a significant effect on the sensitivity of animals to mechanical stimulation. However, EMGPS at a dose of 25 mg/kg together with diclofenac sodium at a dose of 1 mg/kg or etoricoxib at a dose of 1 mg/kg significantly reduced the sensitivity of rats with a model of postoperative pain on days 1, 2 and 3 after surgery.
CONCLUSION
EMGPS at a dose of 25 mg/kg increases the analgesic effect of the non-selective COX inhibitor diclofenac sodium at a dose of 1 mg/kg and the selective COX-2 inhibitor etoricoxib at a dose of 1 mg/kg in mechanical hyperalgesia caused by surgical incisions in rats.