Esketamine Adjuvant Therapy for Patients With Chronic Visceral Pain Comorbid Major Depressive Disorder

Ketamine is a dissociative anesthetic and powerful analgesic. At low doses, ketamine can desensitize the central pain pathway and modulate opioid receptors. Studies have generally found that preoperative use of ketamine can reduce opioid consumption by approximately 50% and sub-anaesthetic doses of it have a rapid antidepressant effect, especially refractory depression. Studies have confirmed that esketamine, the S(+) enantiomer of ketamine, has a stronger affinity for NMDA receptors, which can achieve the same effect at smaller doses. While the incidence of neuropsychiatric side effects is significantly lower. On March 4, 2019, the U.S. Food and Drug Administration (FDA) first approved esketamine nasal spray with a new mechanism of action for the treatment of adult patients with refractory depression. Based on the analgesic and antidepressant effects of ketamine, the investigators speculate that esketamine may be effective for patients with chronic visceral pain comorbid depression. At present, the research evidence in this area is relatively lacking. Therefore, this study aims to explore the difference in the efficacy and safety of esketamine as an adjuvant therapy and positive control drug-pregabalin in patients with chronic visceral pain comorbid depression. Detailed Description: According to the inclusion criteria and exclusion criteria, select patients with chronic visceral pain comorbid depression. Filtering and grouping period: During this phase, the patient will sign an informed consent form, and then conduct a structured clinical evaluation to determine whether it meets the "depressive disorder" in the DSM-IV-TR diagnostic criteria. According to the ICD-11, determine whether the patients have chronic visceral pain. Acute treatment period: Randomize patients into the following treatment groups: intravenous administration of esketamine (3 groups, 0.125, 0.25, 0.50 mg/kg)， and duloxetine is co- administered orally. Pregabalin capsules were administered combined with duloxetine orally. observation period: After 2 weeks, esketamine treatment was discontinued, and observation was continued for 2 weeks. Maintain duloxetine and pregabalin treatment.