***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Purpose Our intention was to assess the effectiveness of preoperative oral melatonin medication on sedation , sleep quality , and postoperative analgesia in patients undergoing elective prostatectomy . Methods Fifty-two ASA I – II patients undergoing elective prostatectomy were included in this study , r and omly divided into two groups . Patients received an oral placebo ( n = 26 ) or 6 mg melatonin ( n = 26 ) the night before and 1 h before surgery . All patients received a st and ard anesthetic protocol . At the end of surgery , all patients received tramadol i.v . via a PCA device . Extubation time , intraoperative fentanyl consumption , and recovery time were assessed at the end of the operation . Pain scores , tramadol consumption , and sedation scores were assessed at 1 , 2 , 4 , 6 , 12 , 18 , and 24 h postoperatively , and sleep quality and subjective analgesic efficacy were assessed at 24 h after surgery . Results There were no significant differences in demographic data between the groups . Extubation time and recovery time from anesthesia were significantly longer in the melatonin group ( P < 0.05 ) . Intraoperative fentanyl usage , pain scores , and tramadol consumption were significantly lower in the melatonin group ( P < 0.05 ) . The postoperative sleep quality of patients was significantly better in the melatonin group than in the control group ( P < 0.05 ) . Postoperative VAS of pain was significantly lower in the melatonin group compared with the control group at 1 , 2 , 4 , 6 , 12 , 18 , and 24 h postoperatively ( P < 0.05 ) . Subjective analgesic efficacy of patients was significantly different between groups ( P < 0.05 ) . The sedation scores were significantly higher in the melatonin group than in the control group at 1 h and 2 h after surgery ( P < 0.05 ) . Conclusions Preoperative oral melatonin administration decreased pain scores and tramadol consumption and enhanced sleep quality , sedation scores , and subjective analgesic efficacy during the postoperative period We have evaluated the perioperative effects of melatonin with those of midazolam in 75 women in a prospect i ve , r and omized , double-blind , placebo-controlled study . Patients were given sublingual midazolam 15 mg , melatonin 5 mg or placebo , approximately 100 min before a st and ard anaesthetic . Sedation , anxiety and orientation were quantified before , and 10 , 30 , 60 and 90 min after premedication , and 15 , 30 , 60 and 90 min after admission to the recovery room . Psychomotor performance was evaluated at these times also , using the digit-symbol substitution test ( DSST ) and the Trieger dot test ( TDT ) . Patients who received premedication with either midazolam or melatonin had a significant decrease in anxiety levels and increase in levels of sedation before operation compared with controls . Midazolam produced the highest scores for sedation at 30 and 60 min after administration and significant psychomotor impairment in the preoperative period compared with melatonin or placebo . After operation , patients who received midazolam or melatonin premedication had increased levels of sedation at 30 min and impairment in performance on the DSST at 15 , 30 and 90 min compared with controls . There were no significant differences between the three groups for anxiety levels or TDT performance after operation . Amnesia was notable only in the midazolam group for one preoperative event ( entry into the operating room ) . Patient satisfaction was noted in the midazolam and melatonin groups only . We have demonstrated that melatonin can be used effectively for premedication of adult patients The objective of the present study was to assess the toxicology of melatonin ( 10 mg ) , administered for 28 days to 40 volunteers r and omly assigned to groups receiving either melatonin ( N = 30 ) or placebo  ( N = 10 ) in a double-blind fashion . The following measurements were performed : polysomnography ( PSG ) , laboratory examinations , including complete blood count , urinalysis , sodium , potassium and calcium levels , total protein levels , albumin , blood glucose , triglycerides , total cholesterol , high-density lipoprotein ( HDL ) , low-density lipoprotein ( LDL ) , and very low-density lipoprotein ( VLDL ) , urea , creatinine , uric acid , glutamic-oxalacetic transaminase ( GOT ) , glutamic-pyruvate transaminase ( GPT ) , bilirubin , alkaline phosphatase , gama-glutamic transaminase ( GGT ) , T3 , T4 , TSH , LH/FSH , cortisol , and melatonin serum concentrations . In addition , the Epworth Somnolence Scale ( ESS ) and a sleep diary ( SD ) were also applied to the volunteers 1 wk before each PSG . In addition , the volunteers were asked about possible side effects ( SE ) that appeared during the treatment . The study was carried out according to the following timetable : Visit 0 , filling out the term of consent and inclusion criteria ; Visit 1 , PSG , laboratory examinations , ESS , SD ,  melatonin serum concentrations ; Visit 2 , SD ,  melatonin serum concentrations , SE ; Visit 3 ,  melatonin serum concentrations , PSG , ESS , SE ; Visit 4 , laboratory examinations , SE , melatonin serum concentrations , SD ; and Visit 5 , PSG , ESS , SE . Analysis of the PSG showed a statistically significant reduction of stage 1 of sleep in the melatonin group . No other differences between the placebo and melatonin groups were obtained . In the present study we did not observe , according to the parameters analyzed , any toxicological effect that might compromise the use of melatonin at a dose of 10 mg for the period of time utilized in this study We have evaluated the level of state and trait anxiety , neuroticism , extroversion and coping style as predictors of the effectiveness of patient-controlled analgesia ( PCA ) in 110 patients undergoing total abdominal hysterectomy . After operation patients were allocated to receive pain control with either PCA or i.m . injections ( IMI ) .  Pain was assessed using the short form McGill pain question naire at 6 , 18 and 24 h after operation , and by recording the amount of analgesic consumed in the first 24 h after surgery . Both state anxiety and coping style were significant predictors of postoperative pain , irrespective of the method of analgesia used . Patients using PCA experienced significantly better pain control than those receiving IMI . However , it was those with high levels of state anxiety who experienced the greatest reduction in pain with PCA . In addition to achieving better pain control , patients who received PCA used significantly less analgesia and were discharged earlier than patients who received IMI Aims : To evaluate the effects of melatonin premedication on anxiety and pain scores of patients , operating conditions , and intraocular pressure during cataract surgery under topical anesthesia . Material s and Methods : Sixty patients were r and omly assigned to receive either sublingual melatonin 3 mg or placebo 60 min before surgery . Verbal anxiety scores and verbal pain scores , heart rate , systolic and diastolic blood pressure , intraocular pressure , and quality of operating conditions were recorded . Results : Melatonin significantly reduced the anxiety scores ( median , interquartile range ) from 5 and 5–3 to 3 and 2–4 after premedication and to 3 and 2–3 during surgery and to 0 and 0–1 postoperatively before discharge from the recovery room . There were significant differences between two groups in anxiety scores after premedication ( 95 % CI 3–3.5 ; P = 0.023 ) , intraoperatively ( 95 % CI 2.5–3.5 ; P = 0.007 ) , and postoperatively ( 95 % CI 0.5–1 ; P = 0.007 ) . The surgeon reported better quality of operating conditions in the melatonin group ( P = 0.001 ) . No significant difference in intraoperative and postoperative pain scores , intraocular pressure , heart rate , and systolic and diastolic blood pressure between two groups was recorded . Conclusion : Sublingual melatonin premedication for patients undergoing cataract surgery under topical anesthesia reduced the anxiety scores in patients and provided excellent operating conditions BACKGROUND : The effect of melatonin on the intraoperative requirements for IV anesthetics has not been documented . We studied the effect of melatonin premedication on the propofol and thiopental dose – response curves for abolition of responses to verbal comm and s and eyelash stimulation . METHODS : This prospect i ve , r and omized , double-blind study included 200 adults with ASA physical status I. Patients received either 0.2 mg/kg melatonin or a placebo orally for premedication ( n = 100 per group ) . Approximately 50 min later , subgroups of 10 melatonin and 10 placebo patients were administered various doses of propofol ( 0.5 , 1.0 , 1.5 , 2.0 , or 2.4 mg/kg ) or thiopental ( 2.0 , 3.0 , 4.0 , 5.0 , or 6.0 mg/kg ) for anesthetic induction . The ability of each patient to respond to the comm and , “ open your eyes , ” and the disappearance of the eyelash reflex were assessed 60 s after the end of the injection of propofol or thiopental . Dose – response curves were determined by probit analysis . RESULTS : Melatonin premedication decreased thiopental ED50 values for loss of response to verbal comm and and eyelash reflex from 3.4 mg/kg ( 95%confidence interval , 3.2–3.5 mg/kg ) and 3.7 mg/kg ( 3.5–3.9 mg/kg ) to 2.7 mg/kg ( 2.6–2.9 mg/kg ) and 2.6 mg/kg ( 2.5–2.7 mg/kg ) , respectively ( P < 0.05 ) . Corresponding propofol ED50 values decreased from 1.5 mg/kg ( 1.4–1.6 mg/kg ) and 1.6 mg/kg ( 1.5–1.7 mg/kg ) to 0.9 mg/kg ( 0.8–0.96 mg/kg ) and 0.9 mg/kg ( 0.8–0.95 mg/kg ) , respectively ( P < 0.05 ) . CONCLUSIONS : Melatonin premedication significantly decreased the doses of both propofol and thiopental required to induce anesthesia Background and objectives : Melatonin ( N‐acetyl‐5‐methoxytryptamine ) is the main indolamine secreted by the pineal gl and . Many studies showed that premedication with melatonin is associated with preoperative anxiolysis and sedation without impairment of cognitive and psychomotor skills and without prolonging recovery . We hypothesized that melatonin decreases the amount of propofol required to produce an adequate depth of hypnosis at induction time . Methods : After approval from the research committee of the anaesthesia department , informed written consent was taken from 45 adult patients undergoing different surgical procedures . They were allocated r and omly into three groups according to the premedication . At 100 min preoperatively , premedication was given in the form of oral melatonin 3 mg ( M3 group ) , oral melatonin 5 mg ( M5 group ) or no premedication ( P group ) . After preoxygenation an anaesthesiologist who was blinded to the premedication injected propofol 10 mg over 5 s every 15 s until the bispectral index ( BIS ) score fell to 45 . The total dose of propofol required to achieve a BIS score of 45 was recorded . Response to verbal comm and s and eyelash reflex was evaluated and correlated to the BIS score and propofol dosage . When a BIS score of 45 was reached , tracheal intubation was accomplished after administration of a narcotic and muscle relaxant . Results : The mean ( st and ard devitation ( SD ) ) induction dose of propofol  producing a BIS score of 45 was 134 ( 25 ) mg in the placebo group vs. 115 ( 19.5 ) and 114 ( 20.9 ) mg in the M3 and M5 groups , respectively ( P < 0.05 ) . The propofol dose required to achieve loss of eyelash reflex and loss of response to verbal comm and s was more in the placebo group . Anxiety score as assessed by visual analogue scale ( VAS ) scored more in the placebo group than both melatonin groups . Time spent in the recovery room did not differ between the three groups . Conclusion : Melatonin premedication , in an oral dose of either 3 or 5 mg , reduced the required dose of propofol to achieve a BIS score of 45 , reflecting a sufficient level of hypnosis for tracheal intubation without prolongation of postoperative recovery room stay Melatonin has been reported to reduce preoperative anxiety . We performed this study to compare preoperative anxiety in elderly patients receiving melatonin ( M ) or placebo ( P ) .  Anxiety was measured in patients aged > 65 yr by a numerical rating scale ( range , 0–10 ) . Each patient was r and omized to receive M 10 m 
    Output:
    
When compared to placebo , melatonin given as premedication ( tablets or sublingually ) can reduce  preoperative anxiety in adults ( measured 50 to 100 minutes after administration ) .
Melatonin may be equally as effective as st and ard treatment with midazolam in reducing preoperative anxiety in adults ( measured 50 to 100 minutes after administration ) .
The effect of melatonin on postoperative anxiety ( measured 90 minutes and 6 hours after surgery ) in adults is mixed but suggests an overall attenuation of the effect compared to preoperatively