Fentanyl, or fentanyl citrate, is an opioid receptor agonist. Fentanyl citrate is a synthetic potent analgesic drug, belonging to the opioid receptor agonists, which is a specially administered anesthetic class of drugs, and can be used for severe pain that occurs before, during, and after surgery. Fentanyl citrate is contraindicated for bronchial asthma, respiratory depression, patients with allergy to this drug, patients with myasthenia gravis are prohibited from using it, the use of which may cause blurred vision, hypotension, nausea, vomiting and other adverse reactions, and in severe cases, bradycardia, respiratory depression, resulting in life-threatening injuries, so the use of the drug should be closely observed to the patient’s condition changes, and if there is any abnormality, deal with it in a timely manner. Fentanyl citrate is addictive and must be used under medical supervision.