<p>  We report a case of intravenous sedation using an opioid in a patient with a chemical dependence on a medical narcotic analgesic.</p><p>  A 77-year-old man with rheumatoid arthritis had used an analgesic (TRAMSET<sup>®</sup>) containing tramadol hydrochloride and acetaminophen for intractable chronic pain for a long period of time. Because he had used the analgesic as an anti-anxiety drug and a sleep-inducing drug, we were concerned that he might be chemically dependent on the opioid.</p><p>  A sequestrectomy of the mandible was planned. Because he had experienced discomfort while receiving local anesthetic injections during previous dental treatments, intravenous sedation was scheduled for his operation. During the first attempt at intravenous sedation, midazolam and propofol were used to manage the sedation. When the operation began, the patient began to act out, resulting in an unrested condition. We then stopped the sedation and the operation was postponed. His state of unrest was suspected to have arisen from intense pain. On our second attempt at sedation, we used a sufficient dose of a narcotic analgesic. We provided sufficient local anesthesia, and we tried to relieve the postoperative pain by adding acetaminophen. As a result, the patient was free from any discomfort and intractable pain.</p><p>  Insufficient analgesia and sedation are known to trigger addiction to opioids ; thus, adequate analgesic use during surgery is critical for patient management, even if a patient has a possible chemical dependency. The present case suggests that anesthesiologists should observe the behavior of patients with possible chemical dependencies and should take such behavior into consideration when selecting the analgesic type and administration dose.</p>