Does Intravenous Midazolam Induce Hyperalgesia?

• Autor(a) principal: Fernandes, Andreia Pereira
• Data de Publicação: 2019
• Outros Autores: Alves, Luís, Coimbra, Luísa, Gouveia, Francisco, Marcos, Ana, Amaro, Leonor, Larmann, Jan, Dahlem, Caroline
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://doi.org/10.25751/rspa.18507
• topic: Artigo Original

Introduction: Benzodiazepines are frequently prescribed to surgical patients as anxiolytic premedication. Evidence suggests that midazolam also impacts on nociception, however, conflicting results have been published reporting both antinociceptive and hyperalgesic effects. Our aim was to assess how intravenous midazolam affects pain and functional outcome after ambulatory knee arthroscopy. Methods: We conducted an observational retrospective cohort study. All patients submitted to arthroscopic knee surgery under spinal anesthesia in our ambulatory surgery center between January 2011 and December 2015 were analyzed. We recorded demographic and clinical data, anesthetic drugs administered, and post-operative pain scores and functional limitations obtained through a telephone interview conducted 24 hours after surgery. The association betweenmidazolam dose and pain, as well as limitations, was estimated by logistic regression, adjusting for age, ASA, opioids and local anesthetics. Results: We included 270 patients. Mean age was 52.2 ±9.6 years, 55.9% of patients were male and 95,9% ASA status 1 or 2. At postoperative day one, 41.8% of patients reported mild or moderate pain, and 58.9% complained of functional limitations. Women reported pain more frequently than men (p = 0.001). Higher doses of midazolam were independently associated with postoperative pain at 24 hours in men, but not in women, with multivariate analyses showing an adjusted OR of 1.73 (IC 95% 1.26–2.37). Conclusion: Our results suggest an association between higher midazolam doses and more frequent report of postoperative pain, in men only. Further studies are needed to evaluate whether this association is due to a true causal relation between midazolam and pain.