Vitaros contains alprostadil, identical to naturally occurring prostaglandin E1, which causes vasodilatation of blood vessels in the corpora cavernosa and an increase in cavernosal artery blood flow, resulting in penile rigidity.1
The efficacy of alprostadil in the treatment of ED is well established when administered by intracavernosal injection or via a transurethral stick.2
Vitaros contains 300 microgram alprostadil in a cream formulation for topical application to the meatus of the penis. The cream incorporates a skin-permeation enhancer that aids absorption of alprostadil through the glans. After application, the onset of action is within five to 30 minutes and the effect lasts for 1-2 hours after dosing.1
Vitaros was assessed for efficacy and safety in two pivotal phase III, double-blind, parallel-group studies in 1732 men aged 21 years and older with a history of ED for at least three months. Among the participants, 22% had diabetes, 29% had cardiac disorders, 13% had undergone prostatectomy and 19% had failed to respond to sildenafil.3
Following initial assessment and a four-week run-in period, patients were randomised to receive topical alprostadil cream (100, 200, or 300 microgram per unit dose) or placebo for use at home as required over 12 weeks. They completed a sexual encounter profile (SEP) diary to record attempts at intercourse.3
The primary efficacy measures were change from baseline to final visit score in the erectile function domain of the International Index of Erectile Function (IIEF) and final visit responses for SEP questions 2 and 3 (relating to successful vaginal penetration and ejaculation, respectively). Patient satisfaction was also assessed using the Global Assessment Questionnaire, where the patient was asked "When using the study medication, did you feel your erections improved?".3
In an integrated analysis of the combined intention-to-treat population from the two trials, all three doses of alprostadil produced statistically significant improvements in IIEF erectile function scores (ranging from +1.7 to +2.5), compared with placebo (–0.7; p≤0.001 for all comparisons). Similar significant improvementsin SEP successful vaginal penetration and ejaculation scores were observed for all doses (p≤0.001 for all).3
Patient satisfaction showed a significant dose-dependent improvement over placebo for all alprostadil doses at 12 weeks: 40% of the 100-microgram group, 47% of the 200-microgram group and 52% of the 300-microgram group reported improved erections, compared with 20% of the placebo group (p<0.001 for all).3
Localised adverse events
Localised penile irritation, including burning, pain and erythema, was the most commonly observed adverse reaction, but was generally transient and mild to moderate in severity. Adverse reactions (eg, vaginal burning) may also occur in partners of patients using topical alprostadil, so use of latex condoms is advised and must be ensured for sexual intercourse with women who are of childbearing potential, pregnant or lactating.1,3
- Vitaros Summary of Product Characteristics, October 2013.
- Becher E. Expert Opin Pharmacother 2004; 5: 623–32.
- Padma-Nathan H and Yeager JL. Urology 2006; 68: 386–91.
Further information: Takeda