Screening of cetirizine for analgesic activity in mice

Background: Pain is the most common symptom for which patients approach doctors. We have multitude of drugs for pain relief, but they have serious side effects ranging from peptic ulcer (e.g. NSAIDs) to renal failure. The other group, opioids have well known side effects ranging from sedation to drug dependence. So a search for a drug for analgesia with high therapeutic effect and fewer side effects will be a boon for the patients. The objective of this study was to find whether cetirizine, a second generation antihistaminic drug, has got any analgesic activity in mice. Methods: Ten adult albino mice weighing 20-30 grams of either sex were randomized to two groups (n=5). Group I: control group (Treated with solvent 0.1 ml/kg), Group II: Test group (Cetirizine 1mg/kg). All drugs were given orally. The analgesic activity was evaluated by using tail flick, tail immersion and tail clip methods. Reaction time of animals to pain sensation before and after Cetirizine administration were noted at 0, 15, 30, 60 and 90 minutes time intervals respectively on Day 1, 3, 5, 7, 10. Results: Mean reaction time was expressed as Mean±SEM, and one way ANOVA was used to assess statistical significance. Cetirizine was found to have statistically significant analgesic effect in mice and time dependent increase in analgesic effect were observed in all three pain models and maximum analgesic activity was observed at 60 minutes (p