Two anaesthesia protocols with short-duration and partially reversible drug combinations were compared for anaesthesia quality and cardio-pulmonary dynamics in free-ranging lions (Panthera leo). A primary anaesthetic drug (ketamine) was separately combined with either of the two α₂-adrenergic receptor agonists, medetomidine or detomidine. Thirty two lions were immobilized, half of which (16) received one of the two drug combination protocols, respectively. Seven quantitative and three subjective categories of data that were compared showed little overall difference in the quality of anaesthesia. However, use of the ancillary drug (detomidine) originally developed for sedation in domestic horses resulted in cost savings of up to five times over the one developed for domestic carnivores (medetomidine). Keeping drug costs down helps to lower the high cost of wild animal immobilizations and is thus particularly useful when routine or frequent capture is required. Short-acting reversible anaesthetics are much preferable in free-ranging situation for short-duration procedures to avoid prolonged recoveries previously experienced with non-reversible alternative anaesthetic agents (tiletamine-zolazepam).