Intraurethral alprostadil for erectile dysfunction: a review of the literature.

The global burden of erectile dysfunction (ED) is increasing. It is estimated that 8-19% of men in Europe have ED and that by 2025 the prevalence of ED worldwide will reach 322 million. The gold standard therapy for ED is an oral phosphodiesterase type 5 (PDE5) inhibitor, but they are not suitable for everyone; approximately 25% of patients do not respond to this therapy and it is contraindicated in others, e.g. those with vascular disease. When PDE5 inhibitors are not suitable, available options include intraurethral and intracavernosal alprostadil - a synthetic vasodilator chemically identical to the naturally occurring prostaglandin E(1) indicated for the treatment of ED. Intraurethral alprostadil is delivered by the Medicated System for Erection (MUSE).- a single-use pellet containing alprostadil suspended in polyethylene glycol administered using an applicator. It is recommended that intraurethral alprostadil be initiated at a dose of 500 µg, as it has a higher efficacy than the 250 µg dose, with minimal differences with regard to adverse events. Data from key clinical studies of intraurethral alprostadil show that it has a fast onset of effect and a good safety profile, with no occurrences of priapism, fibrosis (as seen with intracavernosal injection) or the typical systemic effects observed with oral ED pharmacological treatments. Intraurethral alprostadil has been associated with high patient preference, acceptance rates and quality of life versus intracavernosal injection due to its ease of administration. Evidence has shown that combination treatment with sildenafil may be a possible efficient alternative when single oral or local treatment has failed. Intraurethral alprostadil can be administered in all patients irrespective of ED origin and should be the first option in patients with ED for whom therapy with PDE5 inhibitors has failed or is contraindicated.

A multicenter, randomized, double-blind, crossover study of patient preference for tadalafil 20 mg or sildenafil citrate 50 mg during initiation of treatment for erectile dysfunction.

BACKGROUND: Tadalafil is a phosphodiesterase 5 (PDE5) inhibitor approved in >30 countries for the treatment of erectile dysfunction (ED). It has been shown to improve erectile function compared with placebo in Phase III studies, but clinical experience comparing tadalafil with the PDE5 inhibitor sildenafil citrate is lacking. OBJECTIVE: This study compared patient preference for tadalafil 20 mg or sildenafil 50 mg during initial treatment for ED. It also compared the tolerability of the 2 agents at these doses. METHODS: This randomized, double-blind, fixed-dose, 2-period crossover trial took place at 13 sites in the United States and Germany. Patients were randomized 1:1 to receive 4 weeks of treatment with tadalafil 20 mg or sildenafil 50 mg, followed by the alternative treatment, to be taken as needed up to once daily before sexual activity. RESULTS: The study enrolled 215 men with ED, 109 randomized to the tadalafil-sildenafil sequence and 106 to the sildenafil-tadalafil sequence. Their mean age was 49.8 years; 84.7% were sildenafil naive and 15.3% had undergone a previous inadequate trial of sildenafil. Most patients had moderate ED (60.5%) of >or=1 year's duration (74.9%). Of 190 evaluable patients, 126 (66.3%) preferred to initiate treatment with tadalafil, compared with 64 (33.7%) with sildenafil (P < 0.001). Patients' preference did not differ by age, duration of ED, treatment sequence, or previous sildenafil exposure. Both medications were well tolerated, with no significant differences in the incidence of treatment-emergent adverse events. Headache (11.2% tadalafil, 8.8% sildenafil), dyspepsia (6.0% and 4.2%, respectively), nasopharyngitis (4.7% and 2.8%), and flushing (2.8% and 4.7%) were the most common adverse events. The rate of ocular disturbances was low: 1 patient experienced intermittent bilateral reduction in visual acuity with tadalafil, and 2 exhibited conjunctival hyperemia or eyelid edema with sildenafil. CONCLUSIONS: Tadalafil 20 mg was preferred to sildenafil 50 mg for the initiation of ED therapy in this study population. Both medications were well tolerated.