Because of its potency, Fentanyl quickly became a widely abused substance both on the street and among health care professionals. It comes in liquid form for intravenous use, the Duragesic patch and in lollipop form. Fentanyl effects the central nervous system, causing analgesia(pain relief) and sedation. Other effects include possible mood changes, feeling of euphoria and drowsiness. Fentanyl depresses the respiratory system, so breathing can be slowed. Side effects can include abdominal pain, nausea, dizziness, dry mouth, sweating, urinary difficulty, lack of appetite, depression, diarrhea and, in the worst cases, hallucinations. Signs of overdose include extremely slow respiration, clammy skin, low blood pressure and very slow pulse. Withdrawal should be planned and done slowly through gradual reduction in doses, as Fentanyl is processed or metabolized differently for different users. Withdrawal should always be supervised by a licensed, knowledgeable physician. Many forms or variations of Fentanyl have been manufactured and sold on the streets since its initial introduction. A common form that is almost exclusive to California is called “China White.” Though the effects of Fentanyl are similar to those of Heroine, the chemically reproduced street versions are more likely to be sought after by suburban, as opposed to urban residents. Fentanyl was often given to race horses in the 1970s as a stimulant. In 1979 a racing industry scandal brought about the arrests of several race horse owners and trainers. Use of Fentanyl in Veterinary practice “is limited to surgery in dogs because, like other narcotics, it produces behavioral excitation in some species such as the horse, cat, and mouse” (Henderson, 1998).