Optimizing the therapeutic approach of transurethral alprostadil

Objective To investigate the efficacy and safety of two different starting doses of transurethral alprostadil (250 µg and 500 µg, MUSE ® , Vivus Inc., Menlo Park, CA, USA, and Astra Läkemedel AB, Södertälje, Sweden) and the need for dose titration in a general population with erectile dysfunction. Patients and methods In a 12‐week randomized and open multicentre study with parallel groups, 166 patients were randomised to a starting dose of either 250 or 500 µg of MUSE and evaluated for safety. Of these patients, 142 were included in the analysis of efficacy. MUSE marked in four doses (125, 250, 500 and 1000 µg) was supplied and during the trial the dose could be increased or decreased step‐wise until a satisfactory response was attained. The efficacy was assessed using the Erection Assessment Scale (EAS), as coitus (by diary) and the International Index of Erectile Function. Results The lowest dose of MUSE with which the patients achieved at least one EAS score of 4 or 5 was 125 µg for 1% of participants, 250 µg for 27%, 500 µg for 32%, 1000 µg for 6%, and finally 1000 µg plus a pubic band for 8%. Thirty‐five of the 142 patients (25%) did not report an EAS of 4 or 5. Most patients (> 60%) achieved an EAS of 4 or 5 on the lower doses (125, 250 and 500 µg). Almost all patients who had an EAS score of 4 or 5 also had intercourse. In all, 68% reported sexual intercourse at least once in course of the study. More patients reported penile pain while treated with 500 µg than with 250 µg ( P < 0.05) during the first 4 weeks. However, the penile pain was severe in very few men and it was a minor problem. Hypotensive symptoms were reported six times, independently of dose level. The administration of MUSE was generally rated as comfortable. No patients reported urethral stricture, penile fibrosis, or priapism either in the clinic or at home. Conclusion Recommending 500 µg as a starting dose increased the percentage of patients reporting at least one EAS of 4–5, with or without sexual intercourse, from 28% to 60%. No serious dose‐related systemic effects were seen. When starting on 500 µg, patients were more likely to find directly the dose that gave sufficient response and treatment satisfaction. We suggest that the appropriate starting dose of MUSE should be 500 µg.