BACKGROUND: Preemptive analgesia involves introducing an analgesic prior to the onset of pain stimulation to prevent sensitizing the nervous system to subsequent stimuli that could amplify pain. OBJECTIVE: To treat psychiatric patients with intravenous (i.v.) injection of butorphanol prior to modified electroconvulsive therapy, and to observe its effect on alleviating myalgia after treatment and adverse reactions. DESIGN: A randomized controlled observation. SETTING: Renmin Hospital of Wuhan University.PARTICIPANTS: A total of 120 psychiatric patients, who accepted modified electroconvulsive therapy, were selected from the Mental Health Center of Wuhan University from June to September in 2006. All patients corresponded to the Chinese Classification and Diagnostic Criteria of Mental Disorders, and those with diseases of heart, liver, lung and kidney, glaucoma, intracranial hypertension, hyperthyreosis, and hyperkalemia were excluded. The patients were randomly divided into a control group (n = 60) and treatment group (n = 60). In the control group, there were 42 males and 18 females, aged 17–50 years, with a mean age of (34 ± 11) years. The patients weighed 50–70 kg, with a mean body mass of (63 ± 18) kg. In the treatment group, there were 40 males and 20 females, aged 20–54 years, with a mean age of (36 ± 13) years. The patients weighed 48–72 kg, with a mean body mass of (64 ± 16) kg. Approval was obtained from the Hospitals Ethics Committee. Informed consents were obtained from the patients relatives. A SPECTRUM5000Q multifunctional mobile electroconvulsive therapy apparatus (CORPERATION, USA) was used.METHODS: ① Treatments: In the control group, the patients were anesthetized by I.v. Injection of propofol (AstraZeneca, Italy, No.CN309) containing 0.075% efedrina, and then modified electroconvulsive therapy was performed. Circulation, respiration, and firing of brain electrical activity were continuously monitored. In the treatment group, the patients were I.v. Injected with 1 mg of butorphanol tartrate parenteral solution (Jiangsu Hengrui Medicine Co., Ltd., No.05100732) 5 minutes prior to anesthesia; the remaining treatments were the same as in the control group. ② Evaluations: myalgia conditions were assessed 6 hours after the patients opened their eyes. The patients were evaluated by a visual analogue scale and Ramsay sedation scale immediately, and at 3 minutes and 6 hours after they opened their eyes. MAIN OUTCOME MEASURES: ① Conditions of myalgia. ② Scores of visual analogue scale and Ramsay sedation scale.RESULTS: All 120 psychiatric patients were involved in the final analysis. ① Conditions of myalgia: 6 hours after modified electroconvulsive therapy, 22 patients in the control group and 1 patient in the treatment group complained of myalgia, which resulted in a significant difference between the two groups (P 0.05).CONCLUSION: Preemptive analgesia by butorphanol can effectively alleviate modified electroconvulsive therapy-induced myalgia, without adverse reactions.