A comparative review of apomorphine formulations for erectile dysfunction : Recommendations for use in the elderly

Erectile dysfunction (ED) is a common medical condition that affects the sexual life of millions of men worldwide. First-line oral therapy for ED includes the use of phosphodiesterase type 5 inhibitors (sildenafil, tadalafil and vardenafil) and sublingual apomorphine. Apomorphine is a dopamine D(1) and D(2) receptor agonist that has been approved for marketing in Europe. Different apomorphine formulations have been tested, such as sublingual, subcutaneous and intranasal. However, the sublingual formulation has shown the best results in terms of efficacy, safety and tolerability, especially the 2mg and 3mg doses. Although clinical studies of the efficacy and tolerability of apomorphine sublingual (SL) have included older patients, who are more likely to have ED, no study has specifically assessed the efficacy and tolerability of different doses of apomorphine SL in aging men. Therefore, a MEDLINE search was conducted from January 1987 to November 2005 to identify studies of the efficacy, safety (in particular cardiovascular safety) and tolerability of different apomorphine formulations and doses as treatments for ED in the subcohort of aging men. On the basis of the most recent peer-reviewed publications, the first part of this article critically evaluates data regarding the epidemiology of ED in the aging population. The second part of the article focuses on the mechanism of action and pharmacokinetics of apomorphine both in the general and the elderly population. Finally, a critical analysis of the efficacy and safety of different apomorphine formulations and doses for the treatment of ED is reported. Apomorphine represents a first-line oral treatment for ED. Available formulations include only sublingual administration. Few studies have assessed the efficacy and safety of apomorphine in the elderly population. However, in clinical practice, older patients with multiple vascular risk factors and systematic vascular damage show poor overall response to apomorphine SL for the treatment of ED.