Topical therapies for anal fissure have focused on nitric-oxide donors. These sometimes have undesirable side effects or inconsistent benefits.
Topical phosphodiesterase inhibitors have never been reported in treatment of anal fissure.
In this study, researchers from Spain and the United States assessed the effects of a phosphodiesterase-5 inhibitor, topical sildenafil, in 19 consecutive patients with chronic anal fissure with no previous treatment history.
The team performed station pullthrough manometry with patients in the left-lateral position.
|Discomfort was reported in 26% of patients.|
|Diseases of the Colon and Rectum|
They recorded maximum resting pressure, and then 0.75 ml of 10% sildenafil was then instilled in the anal canal.
The team repeated measurement of maximum resting pressure at the same distance from the anal verge, then measured pressure continuously.
They also recorded the time for initial relaxation and time to maximal relaxation.
Additionally, the team calculated the average resting pressure.
The researchers found that topical administration of 10% sildenafil was accompanied by significant reduction in anal sphincter pressure (18%). Only one patient failed to respond.
They determined that the average onset of action was less than 3 minutes. The maximum effect occurred 1 minute later.
Mild-to-moderate anal discomfort was reported in 26% of patients.
Dr Luis Torrabadella and colleagues concluded, "Topical administration of a phosphodiesterase-5 inhibitor…significantly reduces anal sphincter pressure in patients with chronic anal fissure".
"A beneficial effect of nitric oxide on the spastic anal sphincter has been demonstrated previously".
"This study confirms that this effect need not be derived solely from nitric oxide donors".
"New therapeutic avenues for treatment of anal fissure through indirect enhancement of nitric oxide activity are suggested".