A review of drugs and techniques used for sedation and anaesthesia in captive rhinoceros species.

Captive rhinoceros species are most frequently sedated and/or anaesthetised with the potent opioid, etorphine hydrochloride in combination with an alpha-2 adrenoreceptor agonist or the butyrophenone, azaperone. Carfentanil citrate based combinations have also been used to a lesser extent. In recent years butorphanol tartrate based combinations have been used with good success to induce neuroleptanalgesia. Sedation and anaesthesia are complicated by the large size of all rhinoceros species and their sensitivity to potent opioids. Potential complications include respiratory depression, hypoxaemia, hypertension, pulmonary shunting and ventilation/perfusion mismatch. The pharmacology of the principal drugs used for sedating/anaesthetising rhinoceros is reviewed. Techniques for sedating/anaesthetising the various species and potential complications associated with chemical restraint are discussed.