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

Vet Anaesth Analg. 2017 Jul;44(4):883-889. doi: 10.1016/j.vaa.2017.02.001. Epub 2017 Feb 8.


Objective: 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.

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

Methods: 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.

Results: 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.

Keywords: BAM; azaperone; butorphanol; lion; medetomidine.

MeSH terms

  • Anesthesia, General / methods
  • Anesthesia, General / veterinary*
  • Anesthetics, Combined / administration & dosage*
  • Animals
  • Azaperone / administration & dosage*
  • Blood Pressure / drug effects
  • Butorphanol / administration & dosage*
  • Female
  • Heart Rate / drug effects
  • Immobilization / methods
  • Immobilization / veterinary*
  • Injections, Intramuscular
  • Lions*
  • Male
  • Medetomidine / administration & dosage*
  • Respiratory Rate / drug effects


  • Anesthetics, Combined
  • Azaperone
  • Medetomidine
  • Butorphanol