) Xylazine is a sedative and analgesic as well as a muscle relaxant. Xylazine HCl Injection is used in horses to produce a state of sedation accompanied by a shorter period of analgesia. A sleeplike state is usually maintained for 1-2 hours, while analgesia lasts from 15-30 minutes. Xylazine HCl Injection may be used to calm horses and facilitate handling or during clinical examinations, orthopedic procedures, dental procedures and surgical procedures. Xylazine HCl Injection is also used as a pre-anesthetic to general anesthesia or in conjunction with local anesthetics. Contains 100 mg xylazine per ml. The dosage for Xylazine HCl Injection is recommended at 0.5 ml per 100 lbs body weight by IV administration, or 1.0 ml per 100 lbs body weight by IM administration. Xylazine.