Purpose: We evaluate the response to intraurethral alprostadil administration using the Medicated Urethral System for Erection (MUSE) in unselect men with a history of erectile dysfunction. We determine the effects on blood pressure during in office monitoring and assess safety of this form of treatment. We compare the efficacy of MUSE in an office setting with the placebo controlled pivotal study.
Materials and methods: A total of 115 men with erectile dysfunction underwent in office testing with MUSE following the algorithm recommended by the manufacturer and outlined in the original pivotal study. Patients were asked to rate the rigidity of erection from 1 to 5 with scores 4 and 5 for erections sufficient for intercourse, and level of discomfort from 1 (very uncomfortable) to 5 (very comfortable) at 15-minute intervals. Patients who did not achieve a sufficient erection were scheduled to return for in office testing using the next higher dose up to 1,000 microg. Patient supine and sitting blood pressures were recorded by a nurse before and every 15 minutes after administration. Telephone contact with patients 2 to 3 months after the last in office testing was made to determine whether they were using the system.
Results: Mean plus or minus standard deviation rigidity scores independent of dosage increased from 2.34+/-0.99 at 15 minutes to 2.49+/-0.96 at 30 minutes and decreased thereafter. Although the 1,000 microg. dosage resulted in highest mean score at all times, the differences between dosages were not significant. Rigidity score 4 or 5 was achieved in 13.2% (500 microg.) and 30% (1,000 microg.) of patients at 30 minutes. Mean level of discomfort was 3.6+/-1.2 at 15 minutes and improved thereafter. Comfort levels were not significantly different among dosages. Overall, at 15 minutes 16.8% of patients were uncomfortable (score 1 or 2) and 41.3% were somewhat uncomfortable (1, 2 or 3). For all dosages supine and sitting systolic and diastolic blood pressures decreased significantly from before treatment to 15 minutes and stayed lower during monitoring. Defined by strict criteria 41.2% of patients experienced orthostatic hypotension during in office testing. A total of 21 patients had adverse events, including pain, discomfort and burning in the penis (the most common), dizziness and chest pain. One patient had a syncopal episode and fell in the office. At last followup only 18.6% of the tested patients continued to use MUSE at home, while the remainder discontinued treatment due to pain, insufficient erections for intercourse and cost.
Conclusions: We were unable to achieve similar results to the pivotal study following manufacturer instructions and the algorithm provided by that study. Independent of age and etiology no more than 30% of patients at any given time using any dose achieved erections sufficient for intercourse during in office testing. Because of this limited efficacy, discomfort, pain and burning associated with treatment, and cost, more than 80% of patients did not continue to use MUSE at home.