Volume :
5
Issue :
2
Abstract :
Objective
Dihydropyridines such as cilnidipine and amlodipine have been shown to block not only L-type but also N- type calcium channels. Ketorolac, a peripherally acting NSAID analgesic & tramadol, a centrally acting opioid analgesic are equipotent in treatment of mild to moderate acute pain. This study proposes to find any possible antinociceptive action of amlodipine and whether it potentiates analgesic activity of ketorolac and tramadol.
Methods
Adult healthy Wistar albino rats were grouped into 16 groups. The experiment was carried out using tail- flick method by analgesiometer. Different doses of amlodipine (2.5, 3, 3.5 mg/kg), ketorolac (15, 30, 45 mg/kg) and tramadol (10, 25, 50 mg/kg) and were administered intraperitoneally to select nonanalgesic doses. Different doses of amlodipine was combined with nonanalgesic doses of ketorolac & tramadol to study antinociceptive effect of combinations.
Results
Ketorolac and tramadol showed dose dependent antinociception which peaked at 2 hours. Amlodipine alone showed antinociceptive action at a dose of 3.5 mg/kg after 6 hour of administration. Higher doses of amlodipine (3, 3.5 mg/kg) in combination with nonanalgesic dose of tramadol produced significant antinociception. But Amlodipine at all dose potentiated the antinociceptive action of subanalgesic dose of ketorolac.
Discussion and conclusion
It can be concluded that amlodipine at high dose produced antinociceptive action. Combination of amlodipine with ketorolac and tramadol produced significant enhancement of antinociceptive activity of both tramadol & ketorolac in dose dependent manner.