The objective of our study was to assess the effec- tiveness of combining medicated urethral system for erection (MUSE) with sildenafil citrate in men unsatisfied with the sildenafil alone. Baseline and follow-up data from 23 patients (mean age, 62.5 6 5.23 years) unsatisfied with the use of the sildenafil citrate alone for the treatment of erectile dysfunction following nerve-sparing rad- ical prostatectomy (mean use, 4 attempts/100-mg dose) was ob- tained. All patients started oral sildenafil citrate more than 6 months after radical prostatectomy. Combination therapy was initiated using 100 mg sildenafil citrate orally 1 hour prior to intercourse. Patients used combination therapy for a minimum of 4 attempts prior to as- sessment with the Sexual Health Inventory of Men (International In- dex for Erectile Function-5) and visual analog scale to gauge rigidity (0-100). The effect of therapy on the total International Index for Erectile Function (IIEF) score and penile rigidity score was as- sessed. Of the 23 patients, 4 (17%) had no improvement with the addition of medicated urethral system for erection and discontinued the drug, while 19 (83%) reported improvement with the penile rigid- ity and sexual satisfaction. The IIEF scores of these 19 patients showed significant improvements in each sexual domain, and the patients reported that erection was sufficient for vaginal penetration 80% of the time. Rigidity scores on a scale of 0-100 with sildenafil alone averaged 38% (23-53) for men and 46% (26-67) for their partners. With the addition of MUSE, scores increased to 76% for men and 62% for their partners. We conclude that the addition of MUSE to sildenafil improved sexual satisfaction and penile rigidity in patients unsatisfied with sildenafil alone.