Neuraxial morphine induced pruritus in two cats and treatment with sub anaesthetic doses of propofol.

History: Two cats were presented for orthopaedic surgery.

Physical Examination: With the exception of the orthopaedic injuries found, clinical examination showed no abnormality.

Management: As part of anaesthetic management, one cat received intrathecal morphine, the other epidural morphine. Following recovery, intense grooming was observed. After ensuring adequate analgesia this behaviour was interpreted as pruritus. In the first cat, pruritus was initially managed with medetomidine constant rate infusion (CRI) at 1 and 1.5 μg kg(-1)  hour(-1) . The lower dose produced sedation and no relief from pruritus, the higher dose ablated pruritus but induced sedation. Two propofol (lipid emulsion formulation) boli of 0.1 mg kg(-1) ablated pruritus without causing sedation. The second cat was successfully treated with four boli of 0.1 mg kg(-1) propofol over 20 minutes.

Follow-up: Following treatment with propofol, pruritus did not recur in either cat and both were discharged from the hospital.

Conclusions: This is the first clinical report of morphine-induced pruritus in cats and management with low-dose propofol. These cases suggest an antipruritic mechanism for lipid-formulation propofol.