TITLE:
Effects of Dexamethasone, Clonidine, Tramadol and Nalbuphine on Fentanyl-Induced Hyperalgesia in Rats
AUTHORS:
Camila dos Santos Leite, Naira Correia Cusma Pelógia, Eliane Stevanato, Marília Hidalgo Uchôas, Marta Helena Rovani Pires, Oscar César Pires
KEYWORDS:
Hyperalgesia, Fentanyl, Dexamethasone, Clonidine, Tramadol, Nalbuphine, Rats
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.9 No.12,
December
13,
2021
ABSTRACT: Opioids are drugs used to alleviate pain. However, studies have demonstrated that these drugs can cause an increase in pain sensitivity, which is called opioid-induced hyperalgesia. The objective of this study was to describe the effects of dexamethasone, clonidine, tramadol and nalbuphine on fentanyl-induced hyperalgesia in rats. After obtaining approval from the Committee for the Ethical Use of Animals (CEUA), 36 male Wistar rats were divided into 6 groups: Group 1 (GCSSL) wherein the rats received 1 ml 0.9% saline solution in two injections; Group 2 (GFTSL), received fentanyl at a dose of 100 ug·kg-1 followed by 1 ml 0.9% saline solution via intraperitoneal; the remaining groups (3, 4, 5, 6) received fentanyl at a dose of 100 ug·kg-1 following doses via intraperitoneal: Group 3 (GFTDX), dexamethasone at a dose of 1.0 mg·kg-1; Group 4 (GFTCL), clonidine at a dose of 20 mg·kg-1; Group 5 (GFTTR), tramadol at a dose of 50 mg·kg-1, and Group 6 (GFTNB), nalbuphine at a dose of 5 mg·kg-1. Under general anestesia using isoflurane, the animals were submitted to a surgical incision. Hyperalgesia was evaluated by applying Von Frey filaments at 2 hours after the incision and on the 1st, 3rd and 5th days afterward. At 2 hours after the surgical procedure, there was lower intensity of pain in the fentanyl group (GFTSL) compared to the other groups, and on the fifth day there were no significant differences for pain intensity between groups. The results suggest the presence of fentanyl-induced hyperalgesia and efficacy in its reduction by dexamethasone, clonidine, tramadol and nalbuphine.