Controlled dose delivery in topical treatment of anal fissure: pilot study of a new paradigm.

PURPOSE: Topical nitroglycerin has been widely used as a means for avoiding surgery in patients with anal fissure. However, nitroglycerin has not been universally accepted for this application because of inconsistency of efficacy and side effects. This study compares conventional digital application with precise intra-anal dosing of nitroglycerin using a specialized dose-delivery device and anal cannula.

METHODS

Twenty-six consecutive patients (13 males) with chronic anal fissure and no previous treatment were randomly allocated to receive 0.75 ml of 0.3 percent nitroglycerin ointment (2.25 mg nitroglycerin) t.i.d. intra-anal using the cannula (Group A) or perianally with the gloved finger (Group B). Nitroglycerin dosage was controlled in Group A by the dose-delivery device connected to the cannula and by single-dose preloaded syringes in Group B.

RESULTS

Anal manometry: pressure reduction after application of nitroglycerin was 47 +/- 18.6 in Group A and 20.7 +/- 13.4 percent in Group B (P < 0.01). Headaches were reported by 1 of 10 patients in Group A and 10 of 12 patients in Group B (P = 0.0027). Seven patients of Group B had to be crossed to intra-anal treatment as a result of intensity of headaches. Pain relief was noted by 8 of 10 and 9 of 12 patients in Groups A and B, respectively (P = 0.6). Sphincterotomy was required in only 13.6 percent of all patients.

CONCLUSIONS

Controlled intra-anal dosing of topical nitroglycerin produces a significantly greater reduction in sphincteric pressure and lower incidence of headaches than with perianal administration of the same dose of ointment. These results suggest a new paradigm for increasing safety and efficacy of dose-dependent prescription anal topical medications.