Sublimaze is the brand name for fentanyl injection. The drug is generally used for producing anesthesia for surgery and in the treatment of pain before, during and after surgery. As a narcotic analgesic, Sublimaze works in the brain and nervous system to cause anesthesia and to decrease pain. Sublimaze is generally administered to a patient as an injection at a doctor’s office, hospital or clinic. This medication contains fentanyl, which relieves pain by blocking the nerves in the brain that recognize pain messages from the body. The medication is similar to morphine, but much more potent. As Sublimaze is an opioid, it can be highly addictive, especially when used outside of a doctor’s care. As a Schedule II controlled substance, Sublimaze can produce drug dependence similar to that of morphine.