[A multi-center, randomized, double-blind, placebo-controlled trial of glyceryl trinitrate ointment in the treatment of anal fissure].

Objective To evaluate the clinical efficacy and safety of glyceryl trinitrate (GTN) ointment in the treatment of anal fissure.Methods In this multi-center,randomized,double-blind and placebo-controlled trial,240 chronic anal fissure patients from 7 clinical centers were randomized to receive eight-week treatment with GTN ointment (treatment group) or vaseline ointment (control group) respectively.Healing rate,visual analogue score (VAS),maximum anal resting pressure (MARP) and adverse reactions were recorded and compared.Results A total of 221 patients (92.1％) finished the trial,including 114 patients in treatment group (95.0％,114/120) and 107 in control group (89.2％,107/120).At the endpoint of treatment (56 d),90 patients in treatment group (78.9％,90/114) healed completely compared to 31 patients in control group(29.0％,31/107),and decrease rates of VAS in the two groups were (94.8±15.7)％ and (61.2±35.7)％ respectively,both differences were statistically significant (P＜0.01).MARP after first administration was (20.2± 18.5) mm Hg in treatment group (n=12)and (7.1 ± 14.7) mm Hg in control group (n=6),which was not significantly different (P=0.152).Adverse reaction incidence was higher in treatment group (42.1％ vs.9.3％,P＜0.05),while these adverse reactions were mainly headache and fullness in head,which were self-limiting.Conclusion GTN ointment can effectively promote healing and relieve pain in anal fissure with safety and tolerance. Key words: Chronic anal fissure;  Glyceryl trinitrate ointment;  Randomized controlled trial; Treatment outcomes