Double-blind manometric assessment of two topical glyceryl trinitrate formulations in patients with chronic anal fissures

Background. Chronic anal fissure is a frequent and troubling condition, that may need surgical sphincterotomy for relief of symptoms. However, this approach may yield minor incontinence in up to 30% of cases. Interest has, therefore, recently increased in ″chemical sphincterotomy″ by using topical glyceryl trinitrate ointment. Unfortunately, there is, to date, no specific pharmaceutical preparation of such compound. Aims. To compare, according to a randomized double-blind crossover study, the effects of a pharmaceutical preparation of a specific 0.2% glyceryl trinitrate ointment [PMF 303] and of the common preparation reported in the literature on the anal resting pressure in patients with anal fissure. Patients and Methods. Twelve patients with chronic anal fissure [6 males and 6 females, age range 23-60 years] were recruited for the study. Two paired manometric studies were carried out at one-week intervals. After the basal anal pressure had been assessed, the patients were randomized to receive either one of the two preparations, and manometric measurements were repeated at 20, 40 and 60 minutes. Results. No differences were found between anal resting pressure in the basal study. Both preparations were able to significantly decrease [p=0.001] anal pressure throughout the study period. No significant differences were found between the two preparations. Conclusions. PMF 303 is able to decrease anal pressure in patients with anal fissure, to a similar extent to the widely tested [galenic] literature preparation. Availability of a specific formulation for the treatment of this condition may be clinically useful.