Dose Effect Response of Melatonin Premedication in Oncosurgical Patients: A Randomised Controlled Trial

Abstract

Introduction: Cancer patients experience higher levels of pathological anxiety than other patients. Though several studies have reported perioperative use of melatonin in alleviating preoperative anxiety with minimal side effects, research on the perioperative use of melatonin in oncology patients is scarce. Aim: To analyse the preoperative anxiolysis, sedation, sleepiness and hemodynamic response to intubation after premedication with oral melatonin at two different doses of 0.3 mg/kg and 0.5 mg/kg body weight and comparing them with placebo. Materials and Methods: This was randomised controlled trial on a total of 90 cancer patients aged 18-60 years undergoing elective surgeries under general anaesthesia were randomised into three groups of 30 patients each. Oral melatonin 0.3 mg/kg, oral melatonin 0.5 mg/kg, and placebo were given to patients in Groups A, B, and C, respectively. The Visual Analogue Score (VAS), Ramsay Sedation Scale (RSS), and Stanford Sleepiness Scale (SSS) were used to assess anxiety, sedation, and sleepiness before and 90 minutes after premedication. Heart rate (HR), systolic (SBP), diastolic (DBP), and mean arterial (MAP) blood pressures were also measured. For intragroup comparison, a paired t-test and for intergroup comparison, ANOVA (Analysis of Variance) and difference-in-differences regression analysis were performed. Results: The three groups (group A: oral melatonin 0.3 mg/kg, group B: oral melatonin 0.5 mg/kg, group C: placebo) each having 30 patients were comparable with regard to demographic profiles with insignificant p-value. Melatonin had no significant anxiolytic impact when compared to placebo (p>0.05). However, melatonin offered considerable sedation and haemodynamic stability in a dose-dependent manner. Melatonin 0.5 mg/kg (group B) gave better sedation (RSS score: 3.30±0.11) and haemodynamic stability (fall in Mean Heart Rate: by 7.4 after premedication) than melatonin 0.3 mg/kg) (RSS score: 2.77±0.12; fall in mean Heart rate after premedication: by 7.76) than the placebo (RSS score: 2.17±0.07; fall in mean Heart Rate: by 0.2). Conclusion: Oral melatonin provides better sedation and haemodynamic stability during endotracheal intubation in a dose-dependent manner when compared to placebo. But when required for sole anxiolysis melatonin was similar to placebo. Further studies are warranted to explore the safe dose for the anxiolytic effect of oral melatonin in cancer patients

Keywords

• adjuvant
• anxiety
• haemodynamic
• preoperative
• sedation