Comparison of the effect of Melatonin and Gabapentin on pain and anexiety in patients undergoing cataract surgery with Phacoemulsification with topical anesthesia

The main purpose of sedation in patients under ocular surgery is patient's preparing to stay calm during surgery .Inadequate or deep sedation may lead to patient's sudden movement and subsequently serious complications .
The main purpose of this study is compare the effects of Melatonin and Gabapentin on pain and anxiety during cataract surgery under topical anesthesia.
This study was a single blinded clinical trial conducted on 81 patients undergoing cataract surgery with topical anesthesia in Amir-al-Momenin Academic Hospital in 2014. Patients were randomly assigned into 3 groups:27 patients receiving 6 mg of melatonin tablet,27 patients receiving 600 mg of Gabapentin capsule, and 27 patients receiving placebo(control) 90 minutes pre -operative .In operation room, placebo group received 1 mg Midazolam intravenous, all patients received 0.5 mic/kg Fentanyl . The pain and anxiety were evaluated on premedication time(T1), in the operating room (T2), and post operative (T5).The sedation was evaluated at T1, T2, at the time topical anesthesia(T3), 15 minutes after the start of surgery (T4) and T5.
In our study, there was not statistically significant difference in demographic variables )age, sex and coexisting disease ), the intensity of anxiety and pain in 90 minutes before surgery among the three groups of patients undergoing cataract surgery in the time intervals. It was found that in entering operating room and discharge from recovery, there was a statistically significant difference between mean pain intensity among three groups (p=0.001 and p=0.0001).. In each of the time periods, studying the difference between the intensity of anxiety among the three groups of patients showed a significant difference at the time of entering the operating room between mean anxiety in the three groups (p=0.034). However, there was no significant difference among the mean anxiety of the three groups in recovery discharge time ( p=0.316).
The results show that pretreatment with Melatonin and Gabapentin Midazolam decreased anxiety scores to the same extent of Midazolam. In addition, a single dose of Gabapentin or melatonin administered as pre- medication reduce pain intensity in the patients.