WASHINGTON – Sildenafil may be useful in treating the pain of diabetic neuropathy, Dr. Thomas Brannagan reported in a poster presented at the annual meeting of the American Association of Neuromuscular and Electrodiagnostic Medicine.
Dr. Brannagan, a neurologist at Cornell University, New York, was inspired to conduct the study after diabetic patients taking sildenafil for erectile dysfunction experienced some relief from their neuropathic pain. The trial included eight patients: six men and two women. All reported pain of above 40 on a 0–100 visual analog pain scale, despite receiving one to seven medications each for neuropathic pain.
The patients received an upwardly titrated dose of sildenafil from 25 mg/day the first week to 50 mg/day after week 1 and up to 100 mg/day thereafter, if necessary and tolerated. They also maintained their existing pain medications. Every week they recorded pain on the following scales: 11-point Likert; a 10-point sleep interference; Rand-36 quality of life; and Toronto Clinical Neuropathy.
Two patients discontinued the drug because of rash, while four patients completed the 8-week trial. The four patients experienced a significant reduction in pain, with the average weekly Likert score decreasing from 5.6 at baseline to 1.5, Dr. Brannagan reported.
When all patients were considered, with the last observation carried forward, the average weekly Likert pain score decreased from 6.3 to 3.7. Four patients had a score reduction of more than two points, and three had at least a 50% reduction in pain. Scores in all other areas improved as well: visual analog pain score, 49 to 31; Rand score, 46 to 65; sleep score, 8 to 4; and Toronto score, 12/19 to 10/19, said Dr. Brannagan, who is a consultant for Eli Lilly & Co.