It was aimed with this study to evaluate the cardiorespiratory effects of the combination medetomidine, butorphanol and atropine in cats submitted to Penn hip radiographic exam. Medetomidine, butorphanol and atropine were administered to 100 Persa and cross-bred cats, at 80 μg/kg^-1 IM, 0.5 mg/kg^-1 IM and 0.044 mg/kg^-1 IM, respectively. Variables recorded were heart rate (HR), respiratory frequency (f), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP). Variables were recorded before drugs administration (M0), and after 5, 10, 20, 30, 45, 60 and 90 minutes (M5, M10, M20, M30, M45, M60, M90). Since M20 the animals were positioned to radiographic exam. A Qui-square analysis was performed (P < 0.05). A decrease in HR was detected in M5 and M10 (P < 0.05), a decrease in f from M5 to M90, and an increase in SAP, DAP and MAP was detected in M5 to M30 (P < 0.05), compared to M0. However, during the 90 minutes all parameters were in normal values for the species. The combination medetomidine, butorphanol and atropine is a secure protocol for the Penn hip radiographic exam in cats.

Acknowledgements: to VETNIL for medetomidine donation; to CAPES, for students financial. **This study was approved by the FMVZ--UNESP--Botucatu "Ethical Committee on Animal Experimentation".