Background: Several antidepressants are currently being used as analgesic in neuropathic pain, but their effect on inflammatory pain is not clear. Few studies have shown that duloxetine also has anti-inflammatory effect along with its antinociceptive activity.
Aims and Objectives: The present study was designed to explore the effect of duloxetine on experimentally induced pain and inflammation in animal models.
Materials and Methods: The albino Wistar rats of either sex were randomly divided into four groups, i.e., control and ibuprofen, with six animals in each group. Analgesia was assessed by hot plate method in rats. Paw edema model in rats after induction with 0.1 mL of 1% carrageenan was used to assess the anti-inflammatory activity. Chronic anti-inflammatory activity was assessed by cotton pellet-induced granuloma. The results obtained were analyzed by analysis of variance followed by Tukey HSD post hoc test.
Results: There was a statistically significant increase in reaction time at all time points compared to control in all treatment groups (ibuprofen and duloxetine) in the hot plate methods. Duloxetine (10 mg/kg) is superior to ibuprofen at every time point as shown by increase in mean reaction time. Duloxetine has also shown significant anti-inflammatory effects compared to control. Ibuprofen was found to cause statistically significant decrease in paw size compared to both control and duloxetine in carrageenan-induced rat paw edema. The anti-inflammatory effect of duloxetine was not significant compared to ibuprofen as seen in cotton pellet-induced granuloma.
Conclusion: The present study showed analgesic and anti-inflammatory effect of duloxetine in dose-dependent matter. Thus, duloxetine may fit to be an agent offering analgesic and anti-inflammatory along with its antidepressant activity.
Key words: Analgesic; Carrageenan; Inflammation