Topical Phenytoin 1% for Wound Healing and Postoperative Pain in Patients Under Perianal Fistulotomy

Background and purpose: Postoperative pain is one of the most important complications of anorectal surgeries. Management of these pains would result in improved situations and more satisfaction in patients. The utilization of topical medications is a recommended approach and phenytoin is a preferred option for this method. Hence, this study aimed to invstigate the effects of topical ointment of phenytoin 1%, topical placebo on wound healing, and postoperative pain in patients with perianal fistula after fistulotomy. Materials and methods: This study is a double-blind randomized clinical trial, it was conducted by the 31 codes of research ethics of Iran. In this double-blind randomized clinical trial, 44 patients with anal fistula underwent fistulotomy at Imam Khomeini Hospital in Sari after obtaining informed consent and were randomly selected to receive topical 1% phenytoin ointment or topical placebo twice a day. Phenytoin 1% cream was prepared by Iran Daropaksh Company and the placebo was prepared from Vaseline ointment. The inclusion and exclusion criteria of the study were checked. Medicines were coded in opaque medicine cans and assigned to study groups using a limited randomization method. After that, up to 8 weeks after the operation, pain, recovery, pain caused by defecation, itching, and complications were determined and compared in the groups. Data analysis was done with SPSS software (version 13.0). Chi-Square, Independent-Sample-T test, and Repeated-Measure ANOVA tests were used to compare between 2 groups. Results: A total of 44 patients completed the study and a thorough analysis was carried out. The average age in the intervention group was 43.0±11.8 years and in the control group was 42.1±6.9 years (P>0.05). The patients in the two study groups did not differ in terms of the type of fistula (P>0.05). Postoperative pain from the first to the fifth visit was significantly lower in the phenytoin group compared to the placebo group (P<0.001). Also, the pain after defecation from the first to the fifth visit in the phenytoin group was significantly less than the placebo group (P<0.001). The percentage of recovery from the first to the fifth visit was significantly higher in the phenytoin group compared to the placebo group (P<0.001). There was no statistically significant difference between the intensity of itching among the groups (P>0.05). Wound secretion was observed in the phenytoin group and the control group, respectively, 63.6% and 68.2% (P>0.05). In the phenytoin group, 85.7% of serous and 14.3% of pus were observed, and in the control group, 53.3%, 33.3%, and 13.4% of serous, pus, and blood were observed, respectively (P>0.05). The only complication in the phenytoin group was bleeding, which was observed in 3 patients (13.6%). Conclusion: In general, it can be concluded that 1% phenytoin ointment is effective in wound healing and reducing postoperative pain in patients with anal fistula undergoing fistulotomy. Therefore, the use of this topical medicine is recommended. However, studies with a larger sample size are needed to reach more definitive results. (Clinical Trials Registry Number: IRCT2015041314483N4)