The Clinical Impact of Preoperative Melatonin on... : Anesthesia & Analgesia (original) (raw)

Anesthetic Pharmacology: Research Report

The Clinical Impact of Preoperative Melatonin on Postoperative Outcomes in Patients Undergoing Abdominal Hysterectomy

Caumo, Wolnei MD, PhD*†; Torres, Fernanda MSc‡; Moreira, Nívio L. Jr MD§; Auzani, Jorge A. S. MD§; Monteiro, Cristiano A. MD§; Londero, Gustavo MD§; Ribeiro, Diego F. M.∥; Hidalgo, Maria Paz L. MD, PhD∥

From the *Anesthesia Service and Perioperative Medicine at Hospital de Clínicas de Porto Alegre (HCPA), Universidade Federal do Rio Grande do Sul (UFRGS); †Instituto de Ciências Bśicas da Saúde, Pharmacology Department, UFRGS; ‡Multidisciplinary Group of Development of Biological Rhythms of Universidade de São Paulo; §Registrar of Anesthesia Service and Perioperative Medicine at Hospital de Clínicas de Porto Alegre (HCPA), Universidade Federal do Rio Grande do Sul (UFRGS); ∥Psychiatric Service of Hospital Materno Infantil Presidente Vargas, Hospital de Clínicas de Porto Alegre (HCPA); and ¶Hospital de Clínicas de Porto Alegre (HCPA), Psychiatric Department of School of Medicine, UFRGS, Brazil.

Accepted for publication July 16, 2007.

Supported by the Graduate Research Group (GPPG) at Hospital de Clínicas de Porto Alegre, Brazil.

There was no financial relationship between any of the authors and any commercial interest in the outcome of this study.

Address correspondence and reprint requests to Dr. Maria Paz Loayza Hidalgo, Castro Alves 167 sala 204, CEP 90430-131 – Porto Alegre, RS, Brazil. Address e-mail to [email protected].

BACKGROUND:

Melatonin has sedative, analgesic, antiinflammatory, antioxidative, and chronobiotic effects. We determined the impact of oral melatonin premedication on anxiolysis, analgesia, and the potency of the rest/activity circadian rhythm.

METHODS:

This randomized, double-blind, placebo-controlled study included 33 patients, ASA physical status I–II, undergoing abdominal hysterectomy. Patients were randomly assigned to receive either oral melatonin 5 mg (n = 17) or placebo (n = 16) the night before and 1 h before surgery. The analysis instruments were the Visual Analog Scale, the State-Trait Anxiety Inventory, and the actigraphy.

RESULTS:

The number of patients that needed to be treated to prevent one additional patient reporting high postoperative anxiety and moderate to intense pain in the first 24 postoperative hours was 2.53 (95% CI, 1.41–12.22) and 2.20 (95% CI, 1.26–8.58), respectively. The number-needed-to-treat was 3 (95% CI, 1.35–5.0) to prevent high postoperative anxiety in patients with moderate to intense pain, when compared with 7.5 (95% CI, 1.36–∞) in the absence of pain or mild pain. Also, the treated patients required less morphine by patient-controlled analgesia, as assessed by repeated measures ANOVA (_F_[1,31] = 6.05, P = 0.02). The rest/activity cycle, assessed by actigraphy, showed that the rhythmicity percentual of 24 h was higher in the intervention group in the first week after discharge ([21.16 ± 8.90] versus placebo [14.00 ± 7.10]; [t = −2.41, P = 0.02]).

CONCLUSIONS:

This finding suggested that preoperative melatonin produced clinically relevant anxiolytic and analgesic effects, especially in the first 24 postoperative hours. Also, it improved the recovery of the potency of the rest/activity circadian rhythm.