The correct name for fentanyl is fentanyl transdermal patch, and fentanyl transdermal patch is a potent opioid analgesic. Fentanyl transdermal patch is primarily used to treat moderate to severe chronic pain and those difficult to eliminate pain that can only be treated with opioid-like analgesic medications. Adverse reactions to fentanyl transdermal patch include nausea, vomiting, drowsiness, fainting, insomnia, constipation, sweating, fatigue, chills, and loss of appetite. It may also cause opioid withdrawal when the patient reduces the dosage too quickly or stops taking the drug suddenly, which is manifested as nausea and vomiting, diarrhea and abdominal pain, anxiety and restlessness. Fentanyl transdermal patch is contraindicated in patients who are sensitive to this drug and the included ingredients; contraindicated in the treatment of acute pain or post-surgical pain; contraindicated in patients under forty years of age with non-cancer chronic pain (AIDS, paraplegic pain treatment is not limited by age and history of pain). Fentanyl transdermal patches are regulated as a narcotic drug and should therefore be used with caution by athletes. If you need to use fentanyl transdermal patches, please follow your doctor’s instructions.