P046 The Analgesic Effect of the Combined Treatment of

							P046

The Analgesic Effect of the Combined Treatment of Aspirin with Different
Antidepressants on Thermally and Chemically Induced Pain in Albino Mice

Abdalla Salem Elhwuegi, Kalthom Mahmoud Hassan. Department of Pharmacology and
Clinical Pharmacy, Faculty of Pharmacy, Al-fateh University of Medical Sciences, Tripoli,
Libyan Arab Jamahiriya.



Objectives: By activating multiple pain-inhibitory pathways, combination analgesics can
provide more effective pain relief for a broader spectrum of pain. This research examines the
possible potential analgesic effect of the combined treatment with aspirin and different
classes of antidepressants drugs in two different models of pain using Albino mice.

Methods: Different groups of six animals each were injected intraperitoneally by different
doses of aspirin (50, 100, or 200mg/kg), imipramine (2.5, 7.5, 15 or 30mg/kg), fluoxetine
(1.25, 2.5, 5 or 7.5mg/kg), mirtazapine (1.25, 2.5, or 5mg/kg) and a combination of a fixed
dose of aspirin (100 mg/kg) with the different doses of the three antidepressant drug. One
hour later the analgesic effect of these treatments were evaluated against thermal pain (the
hotplate method) and chemical pain (acetic acid induced writhings). Percentages of pain
inhibition were calculated as a percentage increase in reaction time in the hotplate model or
percentage decrease in writhing in the acetic acid model. All data were subjected to statistical
analysis using MINITAB software.

Results: Aspirin produced dose dependent analgesic effect only against chemically induced
pain. The three selected antidepressants produced dose dependent analgesia against both
types of pain. The addition of a fixed dose of aspirin significantly potentiated the
antinociceptive effect of the lowest and the highest doses of imipramine in the hotplate model,
while this potentiation was statistically significant with all doses of imipramine against
chemically induce pain. The addition of aspirin to fluoxetine significantly potentiated the
analgesic effect of the dose 2.5 mg/Kg in the hotplate model; while this potentiation was
statistically significant with all doses of fluoxetine against chemically induce pain. Finally, the
addition of the selected dose of aspirin significantly potentiated the antinociceptive effect of
the different doses of mirtazapine using both pain models. The locomotor activities of the
animals as measured by the Opto-Varimex Mini activity monitor were not affected by the
different types of treatments except with the highest dose of imipramine and mirtazapine that
produced slight inhibition of motor activities.

Conclusion: The combination of aspirin with an antidepressant might produce better
analgesia. This type of combination can increase the efficacy of pain management and
reduce side effects by using smaller doses of each drug.