Postcastration analgesia in ponies using buprenorphine hydrochloride

Abstract

Buprenorphine has recently obtained UK Marketing Authorisation for horses. The analgesic effects are long lasting, and have considerable potential for postoperative pain relief. This observer blinded, randomised study aimed to evaluate postsurgical analgesia in ponies premedicated with buprenorphine prior to castration under intravenous anaesthesia. Ponies received either 0.01 mg/kg bodyweight (BW) buprenorphine (group B) or an equivalent volume of 5 per cent glucose (group C) given intravenously before induction of anaesthesia. Pain was assessed and recorded using dynamic interactive visual analogue scores (DIVAS 0-100) and a Simple Descriptive Scale (SDS 0-3) (high scores=most pain) before and 1, 3, 6, 9, 12 and 24 hours after anaesthesia. Rescue analgesia was given if DIVAS>40 mm. Data were analysed using the Mann-Whitney U test at P<0.05. Median (range) areas under the curve for DIVAS were 63 (0-383) mm hour in group B and 209 (0-391) mm hour in group C (P=0.0348). The SDS was lower in group B than in group C (P=0.038). Three group B and five group C animals required rescue analgesia. Buprenorphine did not produce any serious adverse effects. Buprenorphine at 0.01 mg/kg BW intravenously administered before anaesthesia provided near-comprehensive postoperative analgesia after surgical castration in ponies.

Pharmacokinetic-pharmacodynamic modelling of intravenous buprenorphine in conscious horses

“…The present study indicates the likely suitability of buprenorphine for equine perioperative analgesia; this has now been demonstrated in ponies where it was used for post‐castration pain relief (Love et al. ).…”

“…In a very recent study, buprenorphine 10 μg kg −1 provided near comprehensive analgesia for 24 hours in ponies undergoing castration (Love et al. ).…”

Antinociceptive effect of buprenorphine and evaluation of the nociceptive withdrawal reflex in foals

“…; Love et al. ). Experimental studies show that analgesic and antihyperalgesic effects are produced in the spinal cord, and additional, non opioid effects, in the brain (Pergolizzi et al.…”

A multicentre, prospective, randomised, blinded clinical trial to compare some perioperative effects of buprenorphine or butorphanol premedication before equine elective general anaesthesia and surgery

“…However, butorphanol, a j agonist, is still most commonly used in horses to provide analgesia and enhance sedation, although it is often regarded as a relatively ineffective analgesic. Butorphanol did not produce better post castration pain control than placebo [11], while in contrast buprenorphine, a partial l agonist, was superior to both butorphanol [12] and placebo [13]. Although morphine and methadone, pure l agonists, would be expected to provide the best opiate analgesia and are quite commonly used in horses, they do not have appropriate UK market authorisation and there are no published clinical studies investigating the analgesic effect of systemic methadone or morphine in horses undergoing general anaesthesia for surgery.…”