A comparison of extradural tramadol and extradural morphine for postoperative analgesia in female dogs undergoing ovariohysterectomy

Abstract

PURPOSE: To compare the postoperative analgesic effects of the extradural tramadol or morphine in female dogs undergoing ovariohysterectomy. METHODS: Sixteen female dogs were randomly assigned to two groups of eight animals each and received morphine (0.1mg kg-1 M group) or tramadol (2mg kg-1 T group). The pre-anesthetic medication was intravenously (iv) acepromazine (0.05mg kg-1). Anesthesia was induced with propofol (4mg kg-1iv) and maintained with isoflurane. The degree of analgesia was evaluated using a numerical rating scale that included physiologic and behavior variables. Dogs were scored at one, three, six and 12 hours after surgery by one blinded observer. Dogs were treated with morphine (0.5mg kg-1) if their scores were >6. Serum cortisol was measured before the pre-anesthetic medication was administered (basal), at the time of the ovarian pedicle clamping (T0), and at 1 (T1), 6 (T6) and 12 (T12) hours postoperative. RESULTS: The pain score did not differ between morphine and tramadol treatments. Rescue analgesia was administered to one dog in the T treatment group. Serum cortisol did not differ between treatments. CONCLUSION: The extradural administration of morphine or tramadol is a safe and effective method of inducing analgesia in female dogs undergoing ovariohyterectomy.

Tramadol Metabolism toO-Desmethyl Tramadol (M1) andN-Desmethyl Tramadol (M2) by Dog Liver Microsomes: Species Comparison and Identification of Responsible Canine Cytochrome P450s

“…However, this use in dogs is controversial, since clinical efficacy studies have produced conflicting results. Some studies indicate that tramadol is equally or more effective than other drugs used to treat pain in dogs (Mastrocinque and Fantoni, 2003;Almeida et al, 2010;Martins et al, 2010;Clark et al, 2011;KuKanich and Papich, 2011;Malek et al, 2012;Neves et al, 2012;Rialland et al, 2012;Kongara et al, 2013;Morgaz et al, 2013;Teixeira et al, 2013;Cardozo et al, 2014), whereas other studies have shown relatively poor analgesic efficacy in dogs (Davila et al, 2013;Delgado et al, 2014;Kögel et al, 2014). Tramadol is considered a prodrug with regard to opioid analgesic effects, requiring metabolic activation by cytochrome P450 (P450) enzymes.…”

2015 AAHA/AAFP Pain Management Guidelines for Dogs and Cats

“…[45][46][47][48] Pharmacodynamic studies demonstrate the anesthestic-sparing and pain-modifying effect of parenteral tramadol in dogs. [49][50][51][52][53] Convincing evidence for a painmodifying effect of oral tramadol, however, remains elusive, and already low plasma levels quickly diminish with sequential administration. [54][55][56][57] one small study of oral tramadol did report a statistically significant increase of mechanical threshold levels in dogs, but only at the 5 and 6 h time points.…”

Preoperative epidural administration of lidocaine-methadone or lidocaine-fentanyl in female dogs undergoing elective ovariohysterectomy

“…The pain scale used in this study has been described for quantifying pain in dogs (PIBAROT et al, 1997;NEVES et al, 2012). No significant difference in analgesia scores was observed between the groups (Table 3) and no animals required rescue analgesia, indicating that the combination of lidocaine with fentanyl or methadone have similar postoperative analgesic efficacy in female dogs undergoing ovariohysterectomy.…”