Volume : 4
Issue : 2
Online ISSN : 2393-9087
Print ISSN : 2393-9079
Article First Page : 88
Article End Page : 94
Introduction: Narcotics like morphine or pethidine are neither widely prescribed, nor readily available as analgesic drugs. Availability of fentanyl is relatively easier, but has tolerability issues and dependence liability. In post-operative setting, fentanyl and promethazine are frequently co-administered. This study aimed at determining the analgesic potential of promethazine in suitable mice models and at studying if combining it with fentanyl could produce analgesia comparable to pethidine, while reducing the dose requirement of fentanyl.
Materials and Method: Dose escalation studies were done to determine subanalgesic doses of fentanyl and analgesic potential of promethazine. Subsequently, analgesia by promethazine in combination with sub-analgesic fentanyl was compared to that caused by pethidine. Five groups of mice were evaluated before and after analgesic dosing. Group I served as vehicle control, Group II received pethidine, Group III and IV received combination treatments with promethazine and sub- analgesic doses of fentanyl, Group V received fentanyl. Evaluation of analgesia were done by tail flick analgesiometer and formalin test.
Results: Formalin test ratings showed equivalent scores in the pethidine group and fentanyl-promethazine combination groups. Tail-flick latency in the fentanyl-promethazine combination groups was significantly increased in comparison to the pethidine group. When promethazine was combined to sub-analgesic fentanyl, Tail-flick latency was also found to be similar to that of full analgesic dose of fentanyl.
Conclusion: The study showed that promethazine had notable analgesic activity in mice. When combined to sub-analgesic doses of fentanyl, promethazine produced better analgesia as compared to pethidine. Combining promethazine to fentanyl reduced the dose requirement of fentanyl without compromising the analgesic efficacy.
Keywords: Analgesic, Promethazine, Fentanyl, Pethidine, Pain Management