Hi there! I am back with news from the veterinary world. This time we have a thematic newsletter, all about African pygmy hedgehog (Atelerix albiventris) analgesia and sedation! 🦔

First, we have a paper on the antinociceptive efficacy and safety of SC buprenorphine hy­drochloride administration. Twelve healthy adult hedgehogs were submitted to three crossover experimental trials:

1. All hedgehogs were given single SC injections of buprenorphine (0.01 mg/kg), buprenorphine (0.03 mg/kg), or saline (0.9% NaCl) solution (0.16 mL/kg). Afterwards, sedation and hind limb ther­mal withdrawal latency were measured.

2. Six hedgehogs were given a single SC injections of buprenorphine (0.05 mg/kg) or saline solution (0.16 mL/kg). Afterwards, sedation and withdrawal latency were evaluated. 

3. Ten hedgehogs were given 3 doses of bu­prenorphine (0.05 mg/kg, SC, q 24 h) or saline solution (0.16 mL/kg, SC, q 24 h), and food intake and body weight were measured for 6 days. 

For all 3 experimental trials, no animals showed any signs of sedation. Buprenorphine is a potent, partial mu opioid receptor agonist that has a longer onset and duration than other opioids, and is considered nonsedating with few adverse side effects, so it makes sense that no animals were sedated. A single 0.01-mg/kg dose of buprenorphine significantly increased thermal withdrawal latency for 36 hours, and single 0.03- and 0.05-mg/kg doses significantly increased latencies for 48 hours. Increased locomotor activity was noted in a few hedgehogs after administration of the 0.03- and 0.05-mg/kg doses; however, it likely has little clinical relevance, considering its short duration and lack of ataxia. Daily administration did not have significant effects on food intake or body weight. It is important to note that the large adipose tissue layer in mantle of hedgehogs may have resulted in delayed absorption due to poor vascularization. The researchers concluded that SC administration of buprenorphine at single doses of 0.01, 0.03, and 0.05 mg/kg provided safe, long-lasting antinociception in African pygmy hedgehogs without apparent sedative effects. The recommendation was of 0.05 mg/kg for severe pain, and 0.01-0.03 mg/kg for mild to moderate pain.

Second, we have a paper on the evaluation of subcutaneous administration of alfaxalone-midazolam and ketamine-midazolam as sedation protocols. Nine healthy adult hedgehogs were used in a randomized, blinded, complete crossover study. Sedation was induced by SC administration of either ketamine (30 mg/kg) with midazolam (1 mg/kg) (KM) or alfaxalone (3 mg/kg) with midazolam (1 mg/kg) (AM), including a 2-week washout period between treatments. Flumazenil (0.05 mg/kg SC) was administered 45 minutes after administration of either protocol to reverse the effects of midazolam. Deep sedation  was produced in 7 of 9 hedgehogs after KM adminis­tration (mean time 6.4 minutes) and all 9 hedgehogs after AM administration (mean time 10 minutes). No significant difference was found in recovery time between sedation protocols, nor in the vital parameters assessments, except for heart rate, which was higher fot the KM protocol. Both groups decreased food intake for 48 hours after sedation, with a significant body weight decrease after KM sedation. Overall, the KM sedation effects were less consistent, with premature arousal occurring in all animals prior to reversal, and had more pronounced effects on food intake and body weight. The researchers then concluded that SC administration of KM and AM provided deep sedation that might be useful to facilitate noninvasive procedures in hedgehogs. These protocols were not found to be sufficient for intubation, since tongue manipulation led to responses in most animals.

Lastly, we have a paper on the use of  low and high SC tiletamine-zolazepam immobilization and effect of flumazenil reversal. Twelve adult hedgehogs received SC injections of tiletamine-zolazepam at 10mg/kg (T10) or 30mg/kg (T30). Forty-five minutes after tiletamine-zolazepam injection, hedgehogs were administered flumazenil or an equivalent volume of saline SC.  Physiologic parameters and food intake were measured after sedation.  Both protocols produced rapid onset of heavy sedation to light anesthesia with minimal effects on cardiorespiratory parameters, which means they could be used for physical exams and minimally invasive procedures. T30 resulted in deeper, more consistent sedation level than T10, so it may serve as a more clinically useful dosage. However, recovery times were significantly longer for T30 group, regardless of flumazenil administration. Jaw tone was reduced in the majority of animals for both dosages, but never lost. It is also good to notice that the hedgehogs became rapidly hypothermic after induction. 

See you next month!