Comparisons Of The Effects Of Medetomidine, Lidocaine And Their Combinations After Lumbosacral Epidural Injection In Goats

Abstract

The present study was carried out in order to compare the behavioral,
analgesic and cardio-pulmonary effects of epidurally administered medetomidine, lidocaine and their combinations in adult Small East African goats. Fourteen adult, healthy, Small East African goats of both sexes were used in this study. Medetomidine was administered at a dose of 20 mg/kg while lidocaine was given at a dose of 4.4 mg/kg body weight.
Similarly, half of the above doses were combined, administered and evaluated for the same parameters. The drugs were administered in a randomized single blinded study, with a one-week interval between subsequent injections. Lumbosacral epidural injection of medetomidine and medetomidine-lidocaine combinations induced behavioral changes
characterized by ataxia, swaying movements, tail flaccidity, low head carriage, sternal and lateral recumbency posture coupled with salivation. Both medetomidine and medetomidine/lidocaine combination induced a significant (P<0.05) decrease of the heart rate (HR) and respiration rate (RR) values within 5 and 10 minutes respectively that persisted for the entire 180 minutes of observation period. In contrast, epidural lidocaine
induced a significant (P<0.05) increase of HR within 5 minutes and thereafter the HR values fluctuated within the normal ranges, no significant changes were observed on RR values. Medetomidine induced moderate raise of Rectal temperature (RT) values within 5 minutes, and followed by a significant fall (P<0.05) one-hour post injection, which persisted for the rest of observation period. No significant difference was noted between medetomidine-lidocaine combinations on RT values. However, lumbosacral epidural injection of 4.4 mg/kg lidocaine induced a sustained increase of RT values throughout (P>0.05). Lumbosacral epidural injection of medetomidine and medetomidine-lidocaine combination induced a generalized analgesia, while lidocaine aloneinduced bilateral flank and perineal analgesia with variable cranial extension. The duration of adequate analgesia was longer with
medetomidine alone than either lidocaine or medetomidine-lidocaine combination. It was therefore concluded that, lumbosacral epidural injection of 20 mg/kg medetomidine induces adequate analgesia of longer duration than either 4.4 mg/kg lidocaine or a combination of half the dose of medetomidine and lidocaine mixed together and given epidurally.

Tanzania Veterinary Journal Vol. 24 (1) 2007: pp. 52-66