The effects of melatonin on anxiety and pain scores of patients, intraocular pressure, and operating conditions during cataract surgery under topical anesthesia

Assessing the Premedication Properties of Sublingual Melatonin in Young Women Undergoing Cesarean Section With Spinal Anesthesia: A Double-Blind Randomized Study

INTRODUCTION

Preoperative anxiety can negatively impact patient outcomes by influencing the intraoperative requirements for anesthetics and analgesics, increasing postoperative pain intensity, and augmenting the need for analgesia. Moreover, it may contribute to higher rates of postoperative morbidity and mortality following certain types of surgery. This study investigates the anxiolytic and sedative properties of sublingual melatonin as a premedication agent in young females undergoing cesarean section under spinal anesthesia.

METHODS

A double-blind, randomized, placebo-controlled trial was conducted in Nasiriyah, Iraq. Eighty females were included, 40 in each group, based on specific inclusion and exclusion criteria. Premedication was administered in the morning, 60 minutes before the procedure. In the melatonin group (M), patients received 10 mg of sublingual melatonin, while the placebo group (P) received placebo premedication. Anxiety and sedation levels were evaluated three times: before taking premedication, five minutes before the insertion of the spinal needle, and one hour postoperatively, using the visual analog scale and Richmond Sedation Scale.

RESULTS

The results show a highly significant P-value regarding anxiety levels between the M Group and P Group (p-value < 0.001). There was a significant difference in the median sedation scores between the studied groups at pre-spinal insertion and postoperatively (p-value < 0.001). The mean heart rate in the M Group was significantly lower than in the P Group (p-value = 0.0019). Significant differences were noted in systolic and diastolic blood pressures between the two groups, measured five minutes before and after spinal needle insertion (p-value < 0.001).

CONCLUSION

These findings contribute to understanding the impact of sublingual melatonin as an anxiolytic and sedative premedication agent on patients undergoing elective cesarean sections under spinal anesthesia. Further research is warranted to fully elucidate the benefits and implications of melatonin administration in such procedures.

Perioperative Anxiety and Depression in Older Adults: Epidemiology and Treatment

The intervals before and after major surgery is a high-risk period for older adults; in this setting, anxiety and depression are common and serious problems. We comprehensively reviewed current evidence on perioperative anxiety and depression in older adults, focusing on epidemiology, impact, correlates, medication risks, and treatment. Principles of perioperative mental healthcare are proposed based on the findings. Prevalence estimates of clinically significant anxiety and depression range from 5% to 45% for anxiety and 6% to 52% for depression, depending on surgical populations and measurement tools. Anxiety and depression may increase risk for surgical complications and reduce patient participation during rehabilitation. Medical comorbidities, pain, insomnia, cognitive impairment, and delirium are common co-occurring problems. Concomitant uses of central nervous system acting medications (benzodiazepines, anticholinergics, and opioids) amplify the risks of delirium and falls. Based on these findings, we propose that anxiety and depression care should be part of perioperative management in older adults; components include education, psychological support, opioid-sparing pain management, sleep management, deprescribing central nervous system active medications, and continuation and optimization of existing antidepressants. More research is needed to test and improve these care strategies.

Experimental Data on the Role of Melatonin in the Pathogenesis of Nonalcoholic Fatty Liver Disease

Despite the increasing prevalence of nonalcoholic fatty liver disease (NAFLD) worldwide, its complex pathogenesis remains incompletely understood. The currently stated hypotheses cannot fully clarify the interrelationships between individual pathogenetic mechanisms of the disease. No appropriate health strategies have been developed for treating NAFLD. NAFLD is characterized by an accumulation of triglycerides in hepatic cells (steatosis), with the advanced form known as nonalcoholic steatohepatitis. In the latter, superimposed inflammation can lead to fibrosis. There are scientific data on NAFLD's association with components of metabolic syndrome. Hormonal factors are thought to play a role in the development of metabolic syndrome. Endogenous melatonin, an indoleamine hormone synthesized by the pineal gland mainly at night, is a powerful chronobiotic that probably regulates metabolic processes and has antioxidant, anti-inflammatory, and genomic effects. Extrapineal melatonin has been found in various tissues and organs, including the liver, pancreas, and gastrointestinal tract, where it likely maintains cellular homeostasis. Melatonin exerts its effects on NAFLD at the cellular, subcellular, and molecular levels, affecting numerous signaling pathways. In this review article, we discuss the experimental scientific data accumulated on the involvement of melatonin in the intimate processes of the pathogenesis of NAFLD.

The Effect of Melatonin on Analgesia, Anxiety, and Intraocular Pressure (IOP) in Cataract Surgery Under Topical Anesthesia

PURPOSE

This study investigated the effect of oral melatonin as a premedication before cataract surgery on pain score, anxiety, surgical conditions, and intraocular pressure (IOP) during cataract surgery with phacoemulsification under topical anesthesia.

DESIGN

This randomized, double-blind prospective study was conducted among 120 patients aged 50 to 80.

METHODS

Patients were randomly assigned to receive either sublingual melatonin 3 mg or placebo 60 min before surgery. Verbal anxiety and pain scores, heart rate, systolic and diastolic blood pressure, intraocular pressure, and quality of surgical conditions were recorded. The results were analyzed using SPSS 23 software, and statistical analysis consisted of χ² test and t-test, and a P value less than .05 was considered significant.

FINDINGS

There was a significant difference between the two groups regarding pain after the surgery before being discharged from the recovery room. The mean pain score in the melatonin group was lower than the placebo group in T4 (in the postoperative ward) (P < .05). The anxiety score of patients was lower in the melatonin group in T3 and T4 (during surgery and in the postoperative ward, respectively) (P < .05). IOP was significantly lower in the case group at the end of the surgery after receiving premedication (P = .021).

CONCLUSIONS

This study showed that 3 mg Sublingual melatonin premedication for patients undergoing cataract surgery under topical anesthesia reduced patients' anxiety scores, pain score, and IOP.

The Effect of Pre-emptive Oral Melatonin versus Placebo on Post-operative Analgesia in Infants after Thoracotomy for Closed Cardiac Surgeries: A Randomized Controlled Study

BACKGROUND: Thoracotomy pain is one of the severest types of pain that should be managed properly, especially in children. Opioids are the most widely prescribed analgesics for post-operative pain, but they can have a number of undesirable side effects. Melatonin could be employed as an adjuvant analgesic therapy during procedural discomfort as it had no known major side effects. STUDY DESIGN: This was a double-blinded, controlled randomized study. METHODS: Fifty patients divided randomly into two equal groups. One hour before surgery, children in M group (n = 25) were given 0.5 mg/kg orally of melatonin 3 mg tablets) and patients in Group P (n = 25) received a placebo (5 ml of water by syringe 5 ml) orally. Post-operative pethidine consumption over the 1st 24 h (mg) was recorded, the intraoperative fentanyl consumption (HR and ABP) at baseline, 1 min after induction, at skin incision, and every 30 min till the end of the surgery were recorded. Neonatal Infant Pain Score (NIPS) at 4 h, 6 h, 8 h, 12 h, 18 h, and 24 h postoperatively was recorded. Other reported data include demographic data, extubation time, days of ICU stay, and complications. RESULTS: Total post-operative pethidine consumption (mg) over 24 h was significantly lower in M group than P group (3.48 ± 2.23 vs. 7.68 ± 4.52 p = 0.01). Intraoperative fentanyl consumption (ug) was significantly lower in M group than P group (10.28 ± 4.98 vs. 17.08 ± 7.39 p < 0.001). As regards NIPS, it was statistically lower in M group than P group in all times except at 8 h and 24 h with significant difference. CONCLUSION: Oral melatonin is an effective and safe pre-emptive drug as it reduces the total post-operative pethidine consumption over the first 24 h and decreased post-operative pain scores without any unpleasant effects in pediatrics undergoing closed heart surgery.

Evaluation of the Effects of Exogenous Melatonin in Zygomatic Complex Fractures

Objective

The objective of this research was to evaluate the benefits of using exogenous melatonin in the preoperative period of patients with zygomatic complex fractures.

Materials and methods

A randomized, triple-blind clinical trial of independent samples was carried out. The sample was divided into two groups: G1 (melatonin) and G2 (placebo). Interventions were standardized with 10 mg melatonin or placebo the night before surgery and 1 h before the start of surgery. The studied variables were level of salivary cortisol, level of anxiety, pain, and use of rescue analgesics. Descriptive and inferential statistical analysis was performed, with a margin of error considered as 5%.

Results

A total of 14 patients were included, and after using the medication, the measurement of cortisol was reduced in the melatonin group (0.48 ± 0.25 to 0.43 ± 0.13 μg/100 ml) and increased in the placebo group (0.19 ± 0.12 to 0.23 ± 0.18 μg/100 ml). There was a reduction in the level of anxiety in the melatonin group and an increase in the placebo group. After two hours of surgery, the pain was statistically less in the melatonin group (4.50 ± 1.38) compared to the placebo group (6.17 ± 0.98). Six hours after surgery, pain showed regression in both groups. Patients in the placebo group (83.3%) used more rescue analgesics than melatonin group (33.3%) in the postoperative period.

Conclusions

Thus, this research demonstrated that melatonin can be effective in reducing salivary cortisol and anxiety after medication, and patients in the melatonin group needed less rescue analgesics in the postoperative period.

Effect of cryotherapy on pain scores and satisfaction levels of patients in cataract surgery under topical anesthesia: a prospective randomized double-blind trial

Objective

To evaluate the effects of cryotherapy on pain scores and satisfaction levels of patients during cataract surgery under topical anesthesia. Eighty patients aged between 55 and 75 years scheduled for cataract surgery were randomly allocated to two study groups to receive topical anesthesia with cryotherapy (TC) or topical anesthesia alone (T) groups. Visual analog pain scores, patient satisfaction level, hemodynamic parameters, and quality of operating conditions were recorded.

Results

Cryotherapy significantly reduced VAS pain scores during surgery (P = 0.014). Although no significant difference in postoperative pain scores, opioid consumption, heart rate, and mean arterial blood pressure was seen in the postoperative period. The surgeon reported better quality of operating conditions in the TC group (P = 0.018). Cryotherapy as a complementary method with topical anesthesia reduced pain scores of patients during surgery. It also produced a better quality of operating conditions for surgeons. There was no significant difference in either postoperative pain scores or opioid consumption.

Trial registration This trial was registered at Iranian clinical trial registering: IRCT registration number: IRCT2017052734091N2

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-06125-w.

Melatonin for pre-medication in children: a systematic review

Background

Melatonin’s effectiveness as an anxiolytic medication has been confirmed in adults; however, its efficacy in a paediatric population is unclear. A number of small studies have assessed its use in children as a pre-operative anxiolytic, with conflicting results.

Methods

We undertook a systematic review of pre-operative melatonin use in children. Four databases (MEDLINE, Embase, the Cochrane Central Register of Controlled Trials and Web of Science), and ‘ClinicalTrials.gov’ were searched for ongoing and completed clinical trials of relevance. Citation tracking reference lists and relevant articles were also accessed. The review was unrestricted by comparator or outcomes. Eleven studies were judged eligible for inclusion. There were high levels of heterogeneity in melatonin administration (in terms of dose and timing). Variable outcomes were reported and included: anxiety; anaesthetic success; analgesia; sedation; post-operative recovery; and safety. Outcomes were not always assessed with the same measures.

Results

Evidence to support melatonin’s anxiolytic properties in this setting is conflicting. Melatonin was associated with reduced sedative effects, post-operative excitement and improved emergence behaviour, compared to comparator drugs. One study reported the benefit of melatonin use on sleep disturbance at two weeks post-surgery. No adverse safety events were identified to be significantly associated with melatonin, affirming its excellent safety profile.

Conclusion

Despite potential advantages, including improved emergence behaviour, based on current evidence we cannot confirm whether melatonin is non-inferior to current “usual care” pre-medications. Further consideration of melatonin as an anxiolytic pre-medication in paediatric surgery is needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03149-w.

Fear and Anxiety Associated with Cataract Surgery Under Local Anesthesia in Adults: A Systematic Review

Cataract surgery is one of the most frequently performed surgical procedures worldwide. Patients usually experience strong negative emotions, such as fear and anxiety. A systematic review of the recent literature regarding the emotional states experienced during cataract surgery under local anaesthesia was performed based on the PubMed and Scopus databases. The objective of this review was to determine the causes and frequency of fear and anxiety, as well as methods for improving intraoperative experience and supporting the patient prior to surgery. Anxiety is mainly caused by fear of the surgery itself, fright of pain, and loss of vision. Abstaining and visual sensations experienced during cataract surgery also increased the preoperative anxiety. Women and hypochondriacs showed higher levels of anxiety. The greatest intensity of negative emotions occurred on the day of the cataract surgery. Patients operated on both eyes experienced greater fear and anxiety before the operation of the first eye surgery. In order to reduce patients’ negative experiences, pharmacological sedation, preoperative education and counselling, manual massage immediately before surgery, and listening to music during surgery are used. Taking this information into consideration allows the introduction of effective methods of eliminating the patient’s negative feelings in connection with cataract surgery, which leads to an improvement in the results of the operation and an increase in the patients’ sense of satisfaction and quality of life.

Effects of preoperative melatonin on postoperative pain following cesarean section: A randomized clinical trial

BACKGROUND

Data regarding the analgesic effects of melatonin after the surgery is scare. So far, only one study has investigated the analgesic effect of melatonin during cesarean section. Objective: The present study was performed to investigate the effect of preoperative oral melatonin on pain intensity after cesarean section during spinal anesthesia.

METHODS

In a double-blind randomized controlled clinical trial study, 204 patients undergoing elective cesarean section with class 1 and 2 anesthesia (ASA) were enrolled. Patients were randomly divided into 3 groups of 68 patients. Patients in group A were given 5 mg melatonin tablets, patients in group B were given 10 mg melatonin tablets, and group C was given placebo. All patients underwent spinal anesthesia with the same anesthesia protocol. Pain intensity, nausea, vomiting, pruritus and headache were assessed and recorded 2, 6, 12 and 24 h after surgery. The time of first dose of analgesia, the amount of opioid consumed within 24 h, and the time to resume physical activity was also recorded. Statistical analysis of data was performed using SPSS 20 software.

RESULTS

Repeated measurements of pain intensity during the study showed that in all 3 groups pain intensity was significantly reduced during the study, p < 0.001, respectively. The intensity of pain was significantly different in groups B and C, groups B and A and groups A and C, P < 0.001, respectively. The pain reduction was greatest in group B, followed by group A and group C, respectively. The time interval between the end of surgery and the patient's need for analgesia was significant in group B compared to group A (P = 0.035) and C (P < 0.001) and also in group A compared to group C (P = 0.011). The mean dose of opioid was significantly least in group B, p < 0.001. The mean time to resume physical activity was also shortest in group B, p < 0.001 Headache and nausea/vomiting were observed in 7 patients (10.7%) group A and 7 patients (10.7%) in group C. None of the patients in group B developed complications.

CONCLUSION

The results of the present study showed that the use of 10 mg of melatonin before cesarean section with spinal anesthesia is not only safe, but also reduces the severity of patients' pain, increases the duration of postoperative analgesia, reduces the need for analgesics after surgery and resumption of physical activity.

The effect of daily life activities on intraocular pressure related variations in open-angle glaucoma

The recent advent of continuous intraocular pressure (IOP) telemetry has led to an increased awareness of the importance of IOP fluctuations, and theories have emerged that IOP variations could play as much a role in glaucoma progression as the mean level of IOP. The aim of the present study was to evaluate the direct effect of common daily activities on IOP-related profiles. Primary open-angle glaucoma and glaucoma suspect patients were prospectively enrolled from specialist clinics at the University of California San Diego (UCSD), USA. Patients were fitted with a SENSIMED Triggerfish (TF) contact lens sensor (CLS) and were instructed to return to their usual daily activities for 24 h. They were asked to record each specific activity or event in a diary. The protocol was repeated twice. The following events were recorded: "walking/cycling", "resistance training", "yoga/meditation", and "emotional stress". CLS measurements recorded 60-to-30 min prior to each event were used as a baseline reference, and all IOP-related fluctuations for 120 min after the start of each event were reported in relation to this reference. Forty relevant events from 22 CLS recordings in 14 patients were retrieved from the diaries. Walking/cycling (n = 10) caused a small but statistically significant elevation of the IOP-related profile during the activity (p = 0.018). Resistance training (n = 11) caused a persistent elevation of the IOP-related profile from the onset of the activity (p = 0.005) through 120 min after the activity was stopped (p = 0.007). Yoga/meditation (n = 4) caused a sustained drop in the IOP-related profiles through to 120 min, although this was not statistically significant (p > 0.380). Emotional stress (n = 13) was associated with a gradual elevation of the IOP-related profile from the start of the stressful stimulus. Both early and late variations were statistically significant (p = 0.038 and p = 0.021, respectively). The present study suggests that emotional stress and resistance training may be associated with persistent IOP-related profile elevation.

Preventive effect of ramelteon on emergence agitation after general anaesthesia in paediatric patients undergoing tonsillectomy: a randomised, placebo-controlled clinical trial

Purpose of this prospective, double-blind, parallel-group, placebo-controlled, randomised clinical trial was to confirm our hypothesis that ramelteon has a preventive effect on emergence agitation after general anaesthesia in children. Patients aged 18 to 119 months (ASA physical status 1 or 2), scheduled to undergo tonsillectomy under general anaesthesia, were randomly allocated to the ramelteon or placebo group. Before general anaesthesia induction, patients in the ramelteon group received 0.1 mg kg⁻¹ of ramelteon dissolved in 5 mL of lactose-containing syrup. The patients in the placebo group received the same amount of syrup alone. The Paediatric Anaesthesia Emergence Delirium score was calculated every 5 min after awakening. The primary outcome was the incidence of emergence agitation (Paediatric Anaesthesia Emergence Delirium score ≥ 10). Paediatric Anaesthesia Emergence Delirium scores, post-operative vomiting incidence, pain scores, and adverse events were secondary outcomes. Fifty patients were enrolled. Forty-eight patients were analysed. There was no significant between-group difference in the incidence of emergence agitation (67% in both groups; risk ratio, 1.0; 95% CI 0.67–1.49; P > 0.99) or any of the secondary outcomes. Our results suggest that 0.1 mg kg⁻¹ of ramelteon does not have a preventive effect on emergence agitation after general anaesthesia in children undergoing tonsillectomy.

Melatonin for preoperative and postoperative anxiety in adults

BACKGROUND

Anxiety in relation to surgery is a well-known problem. Melatonin offers an alternative treatment to benzodiazepines for ameliorating this condition in the preoperative and postoperative periods.

OBJECTIVES

To assess the effects of melatonin on preoperative and postoperative anxiety compared to placebo or benzodiazepines.

SEARCH METHODS

We searched the following databases on 10 July 2020: CENTRAL, MEDLINE, Embase, CINAHL, and Web of Science. For ongoing trials and protocols, we searched clinicaltrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform.

SELECTION CRITERIA

We included randomized, placebo-controlled or standard treatment-controlled (or both) studies that evaluated the effects of preoperatively administered melatonin on preoperative or postoperative anxiety. We included adult patients of both sexes (15 to 90 years of age) undergoing any kind of surgical procedure for which it was necessary to use general, regional, or topical anaesthesia.

DATA COLLECTION AND ANALYSIS

One review author conducted data extraction in duplicate. Data extracted included information about study design, country of origin, number of participants and demographic details, type of surgery, type of anaesthesia, intervention and dosing regimens, preoperative anxiety outcome measures, and postoperative anxiety outcome measures.

MAIN RESULTS

We included 27 randomized controlled trials (RCTs), involving 2319 participants, that assessed melatonin for treating preoperative anxiety, postoperative anxiety, or both. Twenty-four studies compared melatonin with placebo. Eleven studies compared melatonin to a benzodiazepine (seven studies with midazolam, three studies with alprazolam, and one study with oxazepam). Other comparators in a small number of studies were gabapentin, clonidine, and pregabalin. No studies were judged to be at low risk of bias for all domains. Most studies were judged to be at unclear risk of bias overall. Eight studies were judged to be at high risk of bias in one or more domain, and thus, to be at high risk of bias overall. Melatonin versus placebo Melatonin probably results in a reduction in preoperative anxiety measured by a visual analogue scale (VAS, 0 to 100 mm) compared to placebo (mean difference (MD) -11.69, 95% confidence interval (CI) -13.80 to -9.59; 18 studies, 1264 participants; moderate-certainty evidence), based on a meta-analysis of 18 studies. Melatonin may reduce immediate postoperative anxiety measured on a 0 to 100 mm VAS compared to placebo (MD -5.04, 95% CI -9.52 to -0.55; 7 studies, 524 participants; low-certainty evidence), and may reduce delayed postoperative anxiety measured six hours after surgery using the State-Trait Anxiety Inventory (STAI) (MD -5.31, 95% CI -8.78 to -1.84; 2 studies; 73 participants; low-certainty evidence). Melatonin versus benzodiazepines (midazolam and alprazolam) Melatonin probably results in little or no difference in preoperative anxiety measured on a 0 to 100 mm VAS (MD 0.78, 95% CI -2.02 to 3.58; 7 studies, 409 participants; moderate-certainty evidence) and there may be little or no difference in immediate postoperative anxiety (MD -2.12, 95% CI -4.61 to 0.36; 3 studies, 176 participants; low-certainty evidence). Adverse events Fourteen studies did not report on adverse events. Six studies specifically reported that no side effects were observed, and the remaining seven studies reported cases of nausea, sleepiness, dizziness, and headache; however, no serious adverse events were reported. Eleven studies measured psychomotor and cognitive function, or both, and in general, these studies found that benzodiazepines impaired psychomotor and cognitive function more than placebo and melatonin. Fourteen studies evaluated sedation and generally found that benzodiazepine caused the highest degree of sedation, but melatonin also showed sedative properties compared to placebo. Several studies did not report on adverse events; therefore, it is not possible to conclude with certainty, from the data on adverse effects collected in this review, that melatonin is better tolerated than benzodiazepines.

AUTHORS' CONCLUSIONS

When compared with placebo, melatonin given as premedication (as tablets or sublingually) probably reduces preoperative anxiety in adults (measured 50 to 120 minutes after administration), which is potentially clinically relevant. The effect of melatonin on postoperative anxiety compared to placebo (measured in the recovery room and six hours after surgery) was also evident but was much smaller, and the clinical relevance of this finding is uncertain. There was little or no difference in anxiety when melatonin was compared with benzodiazepines. Thus, melatonin may have a similar effect to benzodiazepines in reducing preoperative and postoperative anxiety in adults.

A prospective observational cohort study to evaluate patients' experience during sequential cataract surgery under monitored anesthesia care and topical anesthesia

Cataract surgery is the most common ambulatory surgery at our outpatient surgery center. Several studies have shown that patients with bilateral cataracts may experience different levels of anxiety, pain, and awareness during the first and second cataract extraction.A prospective observational cohort study was conducted at The Ohio State University Wexner Medical Center Eye and Ear Institute in order to compare anxiety, general comfort, awareness, and pain levels in patients undergoing sequential cataract surgeries. Likert and numerical rating scale were used to assess the outcomes. Patients receiving monitored anesthesia care and topical anesthesia were included.A total of 198 patients were enrolled in this study, 116 patients (59%) were female and 157 patients (78%) were Caucasians with a median age of 67 years among participants. Patients with rating "no anxiety" or feeling "somewhat anxious" were significantly higher during surgery 2 (P =< .001). Most of the patients felt "extremely comfortable" during surgery 1 when compared to surgery 2 (54% vs 42.9%; P = .08). No significant differences were found between surgeries regarding intraoperative awareness (P = .16). Overall, patients experienced mild pain during both procedures (92.4% in surgery 1 compared to 90.4% in surgery 2; P = .55). During the postoperative visit, 54% of the patients associated surgery 2 with less anxiety levels, 53% with no differences in general comfort, 60% felt more aware, and 59% had no differences in pain levels.Previous exposure to surgery could have been associated with a significant reduction in anxiety levels reported during surgery 2. Non-pharmacological strategies aiming to reduce perioperative anxiety may be considered an alternative or additional approach to premedication in patients undergoing consecutive cataract surgeries.

Effect of Melatonin on Postoperative Pain and Perioperative Opioid Use: A Meta-analysis and Trial Sequential Analysis

OBJECTIVES

We performed this meta-analysis in order to assess the effect of melatonin on postoperative pain and perioperative opioid consumption.

METHODS

We systematically searched PubMed, EMBASE, and the Cochrane Library until October 2019 for studies concerning the effect of melatonin vs. placebo on postoperative pain. We also searched for grey literature in ClnicalTrials.gov and grey literature databases, including OpenGrey and Grey Literature Report. We performed a meta-analysis of postoperative pain scores, perioperative opioid use, the number of patients with analgesic requirements, the time to the first analgesic requirement, length of hospital stay, and common reported adverse events of melatonin.

RESULTS

According to the inclusion and exclusion criteria, 15 studies with a total of 1,102 patients were included in the final analysis. Melatonin was significantly associated with decreased VAS score (24 hours postoperatively) compared to placebo (trial sequential analysis = conclusive; mean difference [MD] -0.86; 95% confidence interval [CI] -1.38, -0.34; P = 0.001). Patients randomly assigned to melatonin were administered less postoperative opioids than patients in the control groups (trial sequential analysis = inconclusive; MD -3.33 mg; 95% CI -5.28, -1.38; P = 0.0008). The need for analgesic requirements was significantly decreased in the melatonin group. Patients who received melatonin had a significantly longer time to the first analgesic requirement. Compared to the placebo group, there were no significant differences in terms of length of hospital stay, dizziness, headache, paresthesia, and nausea.

CONCLUSIONS

Given the low quality of evidence, minor degree of VAS score reduction, and inconclusive trial sequential analysis of postoperative opioid consumption, this meta-analysis neither supports nor opposes the effect of melatonin on postoperative pain.

Analgesic Efficacy of Melatonin: A Meta-Analysis of Randomized, Double-Blind, Placebo-Controlled Trials

Previous systematic reviews and meta-analyses of randomized controlled trials have reported controversial findings regarding the effects of melatonin on pain reduction. The aim of this study was to evaluate the efficacy of melatonin on pain among adults using a meta-analysis of randomized, double-blind, placebo-controlled trials (RDBPCTs). PubMed, EMBASE, the Cochrane Library, and the bibliographies of relevant articles were searched up to February 2020. Two of the authors independently evaluated eligibility of the studies based on the pre-determined criteria and extracted data. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) for the pain score change were calculated using a random-effects meta-analysis. Out of 463 that met the initial criteria, a total of 30 trials, which involved 1967 participants with 983 in an intervention group and 984 in a control group, were included in the final analysis. In a random-effects meta-analysis, the use of melatonin reduced chronic pain in all the trials (5 studies, SMD -0.65, 95% CI -0.96 to -0.34, I² = 57.2%) and high-quality trials (4 studies, SMD -0.62, 95% CI -1.01 to -0.23, I² = 49.3%). Moreover, the use of melatonin significantly reduced acute postoperative pain (11 studies, SMD -0.82, 95% CI -1.40 to -0.25, I² = 93.0%). However, the subgroup meta-analysis of high-quality RDBPCTs showed no significant association between them (6 studies, SMD -0.21, 95 % CI -0.66 to 0.24, I² = 82.4%). The current study suggests that melatonin might be used in treatment of chronic pain, while there is no sufficient evidence for acute postoperative or procedural pain. Further trials are warranted to confirm its analgesic effect.

Pain Following the Use of Anesthesia Formulation Among Individuals Undergoing Cataract Surgery: A Randomized Controlled Trial

Purpose

To assess the pain intensity of two intracameral anesthetic solutions in patients undergoing cataract surgery and evaluate the factors influencing the patients’ postoperative activities.

Methods

Sixty-two patients undergoing cataract surgery were randomized to receive the study drug – a manufactured solution of 0.02% tropicamide/0.31% phenylephrine/1% lidocaine (Mydrane) or a traditional anesthetic formulation - solution of 1% lidocaine/0.025% adrenaline as an intraocular anesthetic. The pain intensity was assessed by Visual Analog Scale for Pain (VAS Pain) and Brief Pain Inventory-short form (BPI) on the next day after the surgery.

Results

The mean pain score measured preoperatively with VAS Pain was 0.34 in Mydrane group and 0.09 in the reference group (p = 0.51). There were no statistically significant differences between the two anesthetic methods with respect to pain intensity during the surgery (p = 0.94) and the influence of pain during the last 24 h on activity (p = 0.79), mood (p = 0.31), social contacts (p = 0.29), sleep (p = 0.5) and the joy of life (p = 0.39). Additionally, there was no statistically significant influence of age, sex, lateralization, co-existing ophthalmological diseases (p = 0.98) and post-operative complications (p = 0.4) on the experienced pain measured during the surgery and in the last 24 h.

Conclusions

New commercially available intraocular anesthetic solution (Mydrane™) seems to be as effective as off-label traditional anesthetic formulation, in reducing the pain experienced during cataract surgery under topical anesthesia.

The Effect of Melatonin on Anxiety and Pain of Tourniquet in Intravenous Regional Anesthesia

Background:

Melatonin has anxiolytic and potential analgesic effects. Several studies have indicated the sedative and anti-anxiety effects of melatonin when used as premedication before surgery. Hence, we assessed the efficacy of melatonin premedication in tourniquet-related pain and analgesia in patients receiving intravenous regional anesthesia (IVRA).

Materials and Methods:

Fifty patients undergoing elective hand surgery under IVRA were randomly divided into two groups (25 patients each) to receive either melatonin 6 mg (melatonin group) or placebo (control group) as oral premedication. IVRA was achieved with lidocaine, 3 mg/kg, diluted with saline to a total volume of 40 mL. Anxiety scores, sensory and motor block onset and recovery times, tourniquet pain, and 24-h analgesic requirements were recorded.

Results:

The onset of motor and sensory block was statistically significantly shorter in Group M (P < 0.001), and recovery of motor and sensory block was statistically significantly longer in Group M (P < 0.001). The time of starting tourniquet pain was longer in Group M (P < 0.001). The mean anxiety score in the study group was 3 ± 0.81 and in the control group was 4.20 ± 1.04 (P = 0.001). There was a statistically significant difference in the need for opioids between the two groups (P < 0.05).

Conclusions:

Melatonin is an effective premedication before IVRA because it reduces patient anxiety, decreases tourniquet-related pain, and improves perioperative analgesia.

Factors affecting pain in patients undergoing bilateral cataract surgery

PURPOSE

To compare the perceived pain and estimated operative duration among patients undergoing bilateral cataract surgery and to demonstrate correlations with the surgical interval and the demographic and medical characteristics of the patients.

METHODS

A total of 466 patients with cataract who underwent ocular surgery were included. The patients estimated the perceived operative duration and pain they felt during the operation at two times, immediately after surgery and on the first postoperative day; pain was scored using a visual analog scale ranging from 0 (no pain) to 10 (unbearable pain). Patients undergoing bilateral surgeries were divided into four subgroups based on the interval between the two operations (1, 2, 4, or 6 weeks). The perceived pain score and the estimated operative duration were the primary outcomes.

RESULTS

The pain scores were higher for the second surgery than for the first surgery both immediately after surgery (P = 0.043) and on the first postoperative day (P = 0.002). The estimated operative duration was longer for the second surgery (P = 0.001). Only patients who underwent the second surgery at an interval of 2 weeks perceived more pain both immediately and 1 day postoperatively (P = 0.002, P = 0.022) and a longer operative duration (P < 0.001). Gender, age, and education level might also influence the pain score.

CONCLUSIONS

Female patients, patients with a younger age, and patients with higher education level are likely to report more pain. Patients who require bilateral cataract surgery should not undergo the second surgery before an interval of 2 weeks.

Acute emotional stress as a trigger for intraocular pressure elevation in Glaucoma

Background

Stress-induced activation of the sympathetic nervous system leads to a cascade of metabolic reactions. Emotional stress is a more specific form of stress in which the stressor is a psychological response to a situation subjectively perceived as traumatic. Stress hormones can have a wide range of effects on the body, however, it is still unclear if and how it can affect ophthalmic physiology. This report presents a case of severe ocular hypertension in which emotional stress was the only cause elicited, and explores potential aggravating factors.

Case presentation

A 78-year-old, personality type A, lady with a history of pseudo-exfoliative glaucoma presented with an acute asymmetrical raise in intraocular pressure (IOP) immediately following a family breakdown. Her IOP had previously remained stable following a deep sclerectomy in the right eye and an Ex-PRESS shunt in the left eye. Her examination was entirely normal otherwise, with a patent filtration and diffuse bleb as confirmed with anterior segment OCT imaging. Near-normalisation of her IOP was observed within 24 h, concomitantly with the reduction of her stress levels. No other cause for the transient acute hypertensive episode were found.

Conclusions

This case report suggests that acute emotional stress could severely affect IOP in patients suffering from glaucoma. This could be important when looking after glaucoma patients. It would also suggest that the personnality types, and the emotional and social context are more factors to take into account in glaucoma studies. These observations are based on a single case report and would need to be verified on a larger scale.

Efficacy of Preoperative Administration of Acetaminophen and Melatonin on Retrobulbar Block Associated Pain in Cataract Surgery

Background

Retrobulbar block is one of the chosen methods for local anesthesia in cataract surgery. Since it is a painful procedure, using analgesic and sedative drugs is recommended. Current medications have side effects and evaluating of new drugs or new uses of existing safer drugs is necessary.

Objectives

The aim of this study was to compare the administration of melatonin and acetaminophen on pain and hemodynamic changes during retrobulbar block.

Methods

In a double-blinded randomized trial, 180 patients undergoing cataract surgery were randomly divided into three groups: Melatonin group (received melatonin 6 mg), acetaminophen group (received acetaminophen 500 mg), and control group (received placebo). All drugs were administered orally 60 min before arrival to the operating room by nurses blinded to the drugs administered. All patients received fentanyl 0.5 μg/kg before retrobulbar block intravenously. Hemodynamic variables and pain score in each patient were evaluated on arrival in the operating room, during retrobulbar block, during surgery, 20 min after operation, at the end of surgery, and in the recovery room. In case of pain score more than three, additional fentanyl was administered. All data were recorded in structured data sheets.

Results

Data analysis indicated no significant differences among the groups at baseline on any of the demographic variables. Both acetaminophen and melatonin reduced the pain score significantly compared with control during retrobulbar block (P < 0.05 and P < 0.01, respectively). Administration of additional fentanyl was significantly lower in the melatonin group than the control group (P < 0.05). Hemodynamic changes were not significantly different among all groups.

Conclusions

For the first time, as far as we have studied, the analgesic effect of acetaminophen on the retrobulbar block was indicated. We also showed that melatonin can reduce pain during retrobulbar block leading to reduction of additional fentanyl during operation. It seems that both melatonin and acetaminophen may have a beneficial effect on pain control in the retrobulbar block.

Prospective study of anxiety in patients undergoing an outpatient colonoscopy

BACKGROUND

Undergoing a colonoscopy can cause anxiety in patients and this is something which has not been closely studied.

OBJECTIVE

To determine the frequency and intensity of anxiety prior to a colonoscopy and the factors which are related to the procedure.

METHODS

This is a prospective study of patients undergoing outpatient colonoscopy in our hospital. Anxiety was assessed using a visual analogue scale of 0 to 100. The severity of anxiety was rated as mild (1-29), moderate (30-79) or severe (80-100).

RESULTS

Three hundred and twenty-seven patients completed the study, of whom 154 (47.1%) were men with a median age of 54 years (p25-75: 45-65). Three hundred and nine (94.5%) patients were found to suffer a certain degree of anxiety. The median value on the visual analogue scale was 31 (p25-75: 10-53). Anxiety levels were mild in 136 patients (44%), moderate in 141 (45.6%) and severe in 32 (10.4%). Greater anxiety was associated with female patients (mean 40.38 vs 31.99, p = 0.01) and a poorly tolerated previous colonoscopy (mean 50.67 vs 28.44, p = 0.01) and correlated inversely with age (r = -0.170, p = 0.02).

CONCLUSIONS

Colonoscopy causes some degree of anxiety in most patients. Being female, younger and having experienced poor tolerance to a previous scan are associated with greater degrees of anxiety. These findings should be taken into account in the implementation of measures to improve the quality and tolerance of colonoscopy.

Exogenous melatonin in the treatment of pain: a systematic review and meta-analysis

Melatonin is an important hormone for regulating mammalian circadian biology and cellular homeostasis. Recent evidence has shown that melatonin exerts anti-nociception effects in both animals and humans. However, according to clinical trials, the anti-nociception effects of melatonin are still controversial. The aim of this meta-analysis was to investigate the anti-nociception effects of melatonin premedication. The primary outcome was the effects of melatonin on pain intensity. The secondary outcomes included the number of patients with analgesic requirements, total analgesic consumption, and brain-derived neurotrophic factor (BDNF) levels. In total, 19 studies were included in the current meta-analysis. The pooling data show that melatonin significantly decreased the pain intensity, as evidenced by the pain scores. Moreover, melatonin administration also reduced the proportion of patients with analgesic requirements and BDNF levels. However, the effects of melatonin on total analgesic consumption still require further confirmation. Collectively, the current meta-analysis supports the use of melatonin for anti-nociception.

Comparison of clinical outcomes, patient, and surgeon satisfaction following topical versus peribulbar anesthesia for phacoemulsification and intraocular lens implantation: a randomized, controlled trial

Background:

Both cataract surgery and anesthesia techniques are rapidly evolving to become more patient friendly. However, comparison of topical anesthesia (TA) and peribulbar anesthesia (PA) for phacoemulsification and cataract surgery is limited. We evaluated the clinical outcomes and patient and surgeon satisfaction between anesthetic techniques.

Materials and Methods:

This randomized clinical trial was conducted between January and June 2012. Patients were randomly assigned to TA and PA groups for surgery. Visual acuity at 4 weeks postoperatively, status of the cornea and the wound and intraoperative complications were compared between groups at day 1, and 1 and 4 weeks after surgery. Patients and the surgeon completed a close-ended questionnaire on satisfaction with analgesia and comfort. The relative risk (RR) with 95% confidence intervals (CI) was calculated.

Result:

There were 500 patients in each group. There were no significant differences between groups preoperatively. Complications at 1-day postoperatively were significantly greater in the TA group (RR = 1.36, 95% CI: 1.17–1.58). Satisfaction with the mitigation of pain was statistically significantly greater in the PA group compared to the TA group (χ² = 10.9, df = 3, P = 0.001). Surgeons were more satisfied with PA compared to TA (RR = 1.4, 95% CI: 1.34–1.63). There were more anesthesia-related complications in the PA group compared to the TA group.

Conclusions:

Patients who underwent surgery with topical anesthetic experienced lower complications by more pain compared to patients who underwent PA. Topical anesthetic supplemented with analgesic medications could help the patient and surgeon during cataract surgery.

Comparing the Effect of Preoperative Administration of Melatonin and Passiflora incarnata on Postoperative Cognitive Disorders in Adult Patients Undergoing Elective Surgery

Background

Anxiety is a preoperative complication, which most patients encounter. The use of a premedication to reduce preoperative anxiety with minimal cognitive impairment is crucial.

Objectives

This study was conducted to compare the sedative effect of preoperative melatonin and Passiflora incarnata in patients undergoing elective surgery regarding their potential for postoperative cognitive disorders.

Methods

In this clinical trial, 52 patients American society of anesthesiologists grade (ASA) I and II of both genders were selected to receive either Passiflora incarnata (1000 mg nature made) (n = 26) or melatonin (6 mg) (n = 26) as premedication one hour before surgery. Post-operative pain was evaluated using the visual analogue scale (VAS). Patient’s anxiety and cognitive dysfunction was evaluated with the Ramsey score and the digital symbol substitution test (DSST), respectively. All tests were carried out and evaluated at arrival in the operating room, before induction and before discharge from the post anesthesia care unit (PACU).

Results

There were no statistically differences between groups in VAS (P > 0.05). However, the mean score of pain was higher in the melatonin group compared to the Pssiflora incarnata group when discharged from the PACU (27.63 vs. 25.37). The anxiety scores were statistically significant in both drugs (P = 0.001), however higher sedation scores was caused by premedication with melatonin (P = 0.003 vs. 0.008). Regarding the DSST, there was a significant difference between the two groups one hour before the surgery (P = 0.04) and at the time of discharge from the PACU (P = 0.007). When evaluating each group, the Passiflora incarnata group revealed a significant difference (P = 0.003).

Conclusions

Our findings show that premedication with Passiflora incarnata reduces anxiety as well as Melatonin. However, Melatonin causes less cognitive impairment compared to Passiflora incarnata.

Evaluation of the Analgesic Efficacy of Melatonin in Patients Undergoing Cesarean Section Under S pinal Anesthesia: A Prospective Randomized Double-blind Study

Melatonin has been suggested as a new natural pain killer in inflammatory pain and during surgical procedures. We designed this randomized double-blind controlled study to evaluate the analgesic efficacy and also optimal preemptive dose of melatonin in patients undergoing cesarean section under spinal anesthesia . One hundred twenty patients scheduled for cesarean section under spinal anesthesia were randomly allocated to one of three groups of 40 each to receive melatonin 3 milligram (mg) (group M₃), melatonin 6 mg (group M₆) or placebo (group P) sublingually 20 min before the spinal anesthesia. The time to first analgesic request, analgesic requirement in the first 24 h after surgery, hemodynamic variables, anxiety scores nd the incidence of adverse events were recorded. The duration of anesthesia and analgesia didn't show significant differences between three groups. Total analgesic request during 24 h after surgery was different among the three groups (P = 0.035). The incidence of headache in group M₆ was significantly higher than others (P<0.001). However, after adjusting headache between groups of the study, we were unable to show the significant difference in the total analgesic request during 24 h after surgery among the three groups (p = 0.058). Although premedication of patients with 3 mg sublingual melatonin prolonged time to first analgesic request after cesarean delivery compared to placebo group, the difference was not statistically significant. Meanwhile increasing dose of melatonin to 6 mg failed to enhance analgesia and also increase the incidence of headache in patients undergoing cesarean section under spinal anesthesia.

Sub-Tenon's anaesthesia versus topical anaesthesia for cataract surgery

BACKGROUND

Local anaesthesia for cataract surgery can be provided by sub-Tenon's or topical anaesthesia. Both techniques offer possible advantages. This review, which originally was published in 2007 and was updated in 2014, was undertaken to compare these two anaesthetic techniques.

OBJECTIVES

Our objectives were to compare the effectiveness of topical anaesthesia (with or without intracameral local anaesthetic) versus sub-Tenon's anaesthesia in providing pain relief during cataract surgery. We reviewed pain during administration of anaesthesia, postoperative pain, surgical satisfaction with operating conditions and patient satisfaction with pain relief provided, and we looked at associated complications.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE (last search in November 2014) and the reference lists of published articles. We looked for conferences abstracts and trials in progress and placed no constraints on language or publication status.

SELECTION CRITERIA

We included all randomized studies that compared sub-Tenon's anaesthesia versus topical anaesthesia for cataract surgery.

DATA COLLECTION AND ANALYSIS

We assessed trial quality and extracted data in the format allowing maximal data inclusion.

MAIN RESULTS

We included eight studies in this updated review but could retain in the analysis only seven studies on 742 operated eyes of 617 participants. Two cross-over trials included 125 participants, and five parallel trials included 492 participants. These studies were published between 1997 and 2005. The mean age of participants varied from 71.5 years to 83.5 years. The female proportion of participants varied from 54% to 76%. Compared with sub-Tenon's anaesthesia, topical anaesthesia (with or without intracameral injection) for cataract surgery increases intraoperative pain but decreases postoperative pain at 24 hours. The amplitude of the effect (equivalent to 1.1 on a score from 0 to 10 for intraoperative pain, and to 0.2 on the same scale for postoperative pain at 24 hours), although statistically significant, was probably too small to be of clinical relevance. The quality of the evidence was rated as high for intraoperative pain and moderate for pain at 24 hours. We did find differences in pain during administration of local anaesthetic (low level of evidence), and indications that surgeon satisfaction (low level of evidence) and participant satisfaction (moderate level of evidence) were less with topical anaesthesia. There was not enough evidence to say that one technique would result in a higher or lower incidence of intraoperative complications compared with the other.

AUTHORS' CONCLUSIONS

Both topical anaesthesia and sub-Tenon's anaesthesia are accepted and safe methods of providing anaesthesia for cataract surgery. An acceptable degree of intraoperative discomfort has to be expected with either of these techniques. Randomized controlled trials on the effects of various strategies to prevent intraoperative pain during cataract surgery could prove useful.

Melatonin for pre- and postoperative anxiety in adults

BACKGROUND

Anxiety in relation to surgery is a well-known problem. Melatonin offers an atoxic alternative to benzodiazepines in ameliorating this condition in the pre- and postoperative period.

OBJECTIVES

To assess the effect of melatonin on pre- and postoperative anxiety in adults when comparing melatonin with placebo or when comparing melatonin with benzodiazepines.

SEARCH METHODS

The following databases were searched on 19 April 2013: CENTRAL, MEDLINE, EMBASE, CINAHL and Web of Science. For ongoing trials and protocols we searched clinicaltrials.gov, Current Controlled Trials and the World Health Organization (WHO) International Clinical Trials Registry Platform. We reran the search in October 2014. We will deal with any studies of interest when we update the review.

SELECTION CRITERIA

Randomized, placebo-controlled or standard treatment-controlled, or both, studies that evaluated the effect of preoperatively administered melatonin on preoperative or postoperative anxiety. We included adult patients of both genders (15 to 90 years of age) undergoing any kind of surgical procedure in which it was necessary to use general, regional or topical anaesthesia.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two review authors. Data extracted included information about study design, country of origin, number of participants and demographic details, type of surgery, type of anaesthesia, intervention and dosing regimen, preoperative anxiety outcome measures and postoperative anxiety outcome measures.

MAIN RESULTS

This systematic review identified 12 randomized controlled trials (RCTs) including 774 patients that assessed melatonin for treating preoperative anxiety, postoperative anxiety or both. Four of the 12 studies compared melatonin, placebo and midazolam, whereas the remaining eight studies compared melatonin and placebo only.The quality of the evidence for our primary outcome (melatonin versus placebo for preoperative anxiety) was high. More than half of the included studies had a low risk of selection bias and at least 75% of the included studies had a low risk of attrition, performance and detection bias. Most of the included studies had an unclear risk of reporting bias.Eight out the 10 studies that assessed the effect of melatonin on preoperative anxiety using a visual analogue scale (VAS) (ranging from 0 to 100 mm, higher scores indicate greater anxiety) showed a reduction compared to placebo. The reported estimate of effect (relative effect -13.36, 95% confidence interval (CI) -16.13 to -10.58; high quality evidence) was based on a meta-analysis of seven studies. Two studies did not show any difference between melatonin and placebo. Two studies comparing melatonin with midazolam using a VAS found no evidence of a difference in preoperative anxiety between the two groups (relative effect -1.18, 95% CI -2.59 to 0.23; low quality evidence).Eight studies assessed the effect of melatonin on postoperative anxiety. Four of these studies measuring postoperative anxiety 90 minutes postoperatively using a VAS did not find any evidence of a difference between melatonin and placebo (relative effect -3.71, 95% CI -9.26 to 1.84). Conversely, two studies showed a reduction of postoperative anxiety measured six hours after surgery using the State-Trait Anxiety Inventory (STAI) when comparing melatonin with placebo (relative effect -5.31, 95% CI -8.78 to -1.84; moderate quality evidence). Two studies comparing melatonin with midazolam using a VAS did not find any evidence of a difference between the two groups in postoperative anxiety (relative effect -2.02, 95% CI -5.82 to 1.78).

AUTHORS' CONCLUSIONS

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 standard 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.

Safety and Efficacy of Propranolol in Comparison With Combination of Fentanyl and Ketamine as Premedication in Cataract Surgery Under the Topical Anesthesia

This study evaluated the safety and effects of propranolol as a premedication before cataract surgery and compared them with the usual combination doses of fentanyl and ketamine. Among all reffered patients to Feiz Hospital of Esfahan for cataract surgery, 122 patients between Mar to Sep 2010 were enrolled in this study and randomly allocated into one of the following equal groups: 40 mg propranolol, 2 hours before surgery and combination of 15 mg ketamine and 50 µg fentanyl l. 5 min before surgery. The ability to control of hemodynamic instabilities caused by stress and to gain patients satisfaction was compared between two groups. Also, the efficacy of each premedication to control of hemodynamic changes during surgery were evaluated and compared. No significant differences were seen in the patients satisfaction and controlling of stress induced hemodynamic changes between two groups (P>0.05). However, patients in ketamine + fentanyl group showed more nausea and less pain during and after surgery. Moreover, no significant adverse effects were reported during and after the surgery. Our results demonstrated that propranolol can be used safely as a premedication in cataract surgery in the comparable efficacy to ketamine plus fentanyl premedication.

Anxiolytic-like effects of a new 1-N substituted analog of melatonin in pinealectomized rats

In spite of the wide variety of drugs available for treating anxiety, this disorder continues to represent a worldwide health problem that is classified within the first 10 causes of disability. Therefore, the search continues for new antianxiety agents, particularly those not related to benzodiazepines. Even though melatonin has been prescribed as an anxiolytic drug, its use is currently limited due to its short half-life and photo-sensitivity, among other disadvantages. The present study explores the antianxiety properties of a new 1-N substituted melatonin analog, M3C, in pinealectomized rats submitted to two behavioral tests (the cumulative burying behavior paradigm and the elevated plus-maze). Results from both tests show that M3C is effective as an anxiolytic-like agent, at doses lower than any other melatonin analog previously reported. The blocking of these actions by luzindole together with the available data suggests that the anxiolytic properties of M3C are mediated by MT1 and MT2 receptors.