Evaluation the effects of different doses of Melatonin on pain control after surgery and their effects on the need for opioid and non-opioid analgesics in patients who are candidates for spinal anesthesia: a double-blind clinical trial

evaluating the effect of oral melatonin in postoperative pain control and its effect on the need for opioid and non-opioid analgesics.

A randomized, double-blind, parallel-group, controlled, phase 3 clinical trial on 152 patients. For randomization, eight random block permutations method was used.

The location of this study is Apadana Hospital in Ahvaz and Patients who meet the conditions for entering the study are randomly divided into 4 groups, including group A with a dose of 3 mg of melatonin, group B with a dose of 10 mg of melatonin, group C with a dose of 20 mg of melatonin, and group D with a control group. After obtaining written consent from the patients, half an hour before the start of spinal anesthesia, the drug or placebo (a placebo similar to the drug in terms of size and appearance) is given to the patients. From the time of receiving the drug until 24 hours after the end of Surgery, patients are regularly monitored.

Entry conditions: 1. Be over 18 years old. 2. Candidate patients for spinal anesthesia 3. Completing the informed consent form Exclusion conditions: 1. Patients with liver failure (liver enzymes more than 3 times the normal limit) 2. Patients with kidney failure (GFR<60) 3. Pregnancy 4. Patients with brain tumors. 5. Patients who have a history of neurological and psychological diseases. 6. People who take warfarin. 7. Drug abuse 8. History of sensitivity to melatonin 9. The patient's unwillingness to continue participating in the study at any time

4 intervention groups including the first group with a dose of 3 mg of melatonin, the second group with a dose of 10 mg of melatonin, the third group with a dose of 20 mg of melatonin, and the fourth group with a control group

Pain intensity and the amount of opioid and non-opioid drugs used

The randomization process is done with Random Allocation Software and the block method is used, and the block size is 8 people and the number of blocks is 19 items. The randomization unit is individual. In order to hide the treatment allocation, the list of treatments are placed in sealed and numbered envelopes (to preserve the order of the sequence).

Randomization will be done based on the method of random block permutations of eight. Before starting the sampling, the drugs are coded at the time of manufacture in the Faculty of Pharmacy. And the drugs are given to volunteer patients by a nurse who has no role in data collection and data analysis. The participant and the researcher who collects the data and evaluates the patients do not know the type of patient intervention.