Evaluation of BAM (butorphanol–azaperone–medetomidine) in captive African lion (Panthera leo) immobilization



The combination of butorphanol, azaperone and medetomidine (BAM) with subsequent antagonism by naltrexone–yohimbine or naltrexone–atipamezole was evaluated for reversible immobilization of captive African lions (Panthea leo).

Study design

Prospective, clinical trial.


Twenty lions, 11 males and nine females, weighing 38–284 kg were immobilized in South Africa.


The BAM volume dose rate administered was 0.005–0.008 mL kg−1 (0.6 mL 100 kg−1). Physiologic variables were recorded every 5 minutes. Four arterial blood samples were collected from all animals at 20, 30, 40 and 50 minutes after immobilization for analysis of blood-gases and acid-base status.


The actual doses administered were as follows: butorphanol, 0.18 ± 0.03 mg kg−1; azaperone, 0.07 ± 0.01 mg kg−1; and medetomidine, 0.07 ± 0.01 mg kg−1. The inductions were calm and smooth, and induction time ranged from 4 to 10 minutes (7 ± 2 minutes). The amount of time needed to work with each lion was 70 minutes, and no additional drug doses were needed. Heart rate (40 ± 8 beats minute−1) and respiratory frequency (15 ± 4 breaths minute−1) were stable throughout immobilization. The mean arterial blood pressure of all animals was stable but elevated (142 ± 16 mmHg). The rectal temperature slightly increased over time but remained within acceptable range. The recovery time was significantly shorter when using naltrexone and atipamezole (9 ± 1 minutes) compared to using naltrexone and yohimbine (22 ± 7 minutes).

Conclusion and clinical relevance

The BAM combination proved to be reliable for general veterinary anaesthesia in lions. During anaesthesia, minor veterinary procedures such a blood collection, intubation, vaccination and collaring could safely be performed with no additional dosing required.