There is one drug used in anesthetic protocols that should not be used in the Boxer. That drug is Acepromazine, a tranquilizer, that is often used as a preanesthetic agent. In the Boxer, it tends to cause a problem called first degree heart block, a potentially serious arrythmia of the heart. It also causes a profound hypotension (severe lowering of the blood pressure) in many Boxers that are given the drug. Recently on the Veterinary Information Network, a computer network for practicing veterinarians, an announcement was placed in the cardiology section entitled "Acepromazine and Boxers". This described several adverse reactions to the drug in a very short time span at a Veterinary Teaching Hospital. All the adverse reactions were in Boxers. The reactions included collapse, respiratory arrest, and profound bradycardia (slow heart rate, less than 60 beats per minute). The announcement suggested that acepromazine should not be used in dogs of the Boxer breed because of a breed-related sensitivity to the drug.