Niveles plasmáticos de melatonina en la hipnosis anestésica en humanos con midazolam y propofol

Abstract

Background: Studies of the narcotic and sedative effects of melatonin seem to demonstrate certain hypnotic capacity. Therefore some hypnotic drugs would be related with an increase in plasma melatonin levels. Methods: We searched for the influence of propofol and midazolam administration on this way in thirty healthy patients undergoing spinal anesthesia for lower limb procedures. Patients were randomly assigned in three groups: midazolam sedation (0.05-0.1 mg/kg/h), propofol sedation (3-4 mg/kg/h) and anesthesia without sedation. A basal control group and a theoretical reference curve were also compared. Melatonin levels were measured at 10 and 60 min after initiating sedation and 90 min after withdrawing it. Basal levels were obtained in all groups. Results: The patients showed no differences in basal levels (P>0.269). Circulating melatonin concentrations did not vary at 60 min after initiating sedation (P=0.491) or 90 min after stopping it (P>0.093). Statistical differences were detected 10 min after initiating sedation between the no sedation group respect to the propofol (P<0.001) and reference curve (P<0.000) groups. Conclusions: Due to propofol produces a plasma melatonin peak we suggest an effect of this hypnotic drug on the pineal gland. Midazolam doesn't increase or decrease plasma melatonin levels.