Fentanyl is an opioid medication that is sometimes called a narcotic and is used as part of anaesthesia to help prevent pain after surgery or other medical procedure. Dosage form that applies to Fentanyl includes tablet, film, spray, or troche/lozenge. Some side effects caused by this medicine include labored or difficult breathing, chest pain, dry mouth, fever or chills, cough, and convulsions. Fentanyl should not be used a patient who is allergic to Fentanyl or other narcotic pain medicines. Misuse of this drug might cause overdose, addiction or death especially by a person who is taking it without a prescription or a child.