Topical 0.2 percent glyceryl trinitrate ointment has a short-lived effect on resting anal pressure

Glyceryl trinitrate ointment applied to the anal verge lowers anal resting pressure, but its duration of action is uncertain. This study investigated the effect and duration of action of 0.2 percent glyceryl trinitrate on anal resting pressure and hemodynamic parameters.

A total of 15 volunteers, 9 male, with a median age of 30 (range, 20-71) years, underwent continuous static anal manometry using a solid state catheter for ten minutes before and two hours after applying 0.2 percent glyceryl trinitrate ointment to the anoderm with a gloved finger. Pulse and blood pressure were recorded every 15 minutes.

A significant reduction in maximal anal resting pressure compared with preglyceryl trinitrate values was observed at 15, 30, 45, 60, and 90 minutes after application, but no significant difference thereafter. There was no significant change in pulse during the study. Systolic and diastolic blood pressures dropped significantly after application of glyceryl trinitrate, but had recovered and were not significantly different from original values after 90 minutes. A significant fall in blood pressure did not correlate with the onset or duration of side effects.

Continuous static manometry (as opposed to interval measurements reported in previous studies) demonstrates that 0.2 percent glyceryl trinitrate ointment significantly lowers anal resting pressure, but only for 90 minutes. Twice daily application of topical 0.2 percent glyceryl trinitrate heals two-thirds of fissures after eight weeks, but its apparently short duration of action may indicate that more frequent application might heal more fissures, more rapidly.