The affective experience and use of opioids before anesthetic induction: a double blind randomized clinical trial

• Grant number: 24/05829-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2024
• End date: May 31, 2026
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Guilherme Antonio Moreira de Barros
• Grantee: Luiz Carlos Mendes Campo Dall'Orto
• Host Institution: Faculdade de Medicina (FMB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Opioids are commonly used, mainly for the treatment of surgical andpost-surgery pain. Considered standard procedure for anesthesia, opioids are generallyadministered to patients before the hypnotic used for general anesthetic induction. Although theopioid analgesics are known to cause certain side effects, their effects onthe subjective emotional (affective) state of patients are less described. Until now, there are no studies that have analyzed the short-term effects of opioid analgesics on affective emotions,in the stress response at sedation level in a clinical environment (operating room). Consequently, the present study will contribute to knowledge about affective reactions todifferent opioid analgesics and will provide information to optimize pre- andpost-operative care and pain control plans. This is a Phase IV clinical studyrandomized, double-blind, placebo-controlled, with two drug trials in healthy adult patients undergoing surgical procedures, to investigate and compare the short-term affective effectsof morphine and methadone, administered intravenously to participantsbefore induction of general anesthesia. And as secondary objectives, identify predictors of usepostoperative opioids and chronic postoperative pain. Our hypothesis is that the mental state of patients, that is, the affective effects exerted by opioids differ whenused a few minutes before anesthetic induction. The sample size wascalculated considering a prevalence of 21% regarding the negative effect of opioids inpatients who have no previous experience with the drug, with a margin of error of 5% andreliability of 95%, the minimum sample size is 255 participants, who will berandomized into three groups of 85 subjects each, namely a morphine group, a methadone group anda placebo group. Specifically for this study, patients answer standardized questions on their well-being and affective state before and after opioid administration.Participants will be randomized to receive placebo or one of two commonly used opioids used in surgeries before the induction of general anesthesia, in one of two equianalgesic doses. This research has an international partnership, was submitted and will only beginafter approval by the Research Ethics Committee of the Faculty of Medicine of Botucatu,in accordance with Resolution 466/12 of the National Health Council and registered on theBrazilian Clinical Trials Registry (REBEC).