RESUMEN
<p><b>OBJECTIVE</b>To evaluate the clinical efficacy and safety of glyceryl trinitrate (GTN) ointment in the treatment of anal fissure.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>GTN ointment can effectively promote healing and relieve pain in anal fissure with safety and tolerance.</p>