Drug Insight: oral phosphodiesterase type 5 inhibitors for erectile dysfunction.
Erectile dysfunction (ED) is a common medical condition that affects the sexual life of millions of men. At present, first-line oral pharmacotherapy for most patients with ED is a phosphodiesterase type 5 (PDE-5) inhibitor, of which three are currently available worldwide. Sildenafil (Viagra, Pfizer) has a very satisfactory efficacy-safety profile in all patient categories. The first PDE-5 inhibitor to reach the market, it is now the most widely prescribed oral agent for ED. Tadalafil (Cialis, Lilly ICOS) and vardenafil (Levitra, Bayer/GlaxoSmithKline) were introduced to the European Union and the US in 2003 and 2004, respectively. These three PDE-5 inhibitors share many characteristics, but each has unique features. This review describes the chemical, pharmacologic and clinical features of sildenafil, vardenafil and tadalafil as oral first-line treatments for ED. First, we describe the physiology of penile erection and PDE-5 inhibitor pharmacology, including chemistry, PDE selectivity, pharmacokinetics, and possible drug interactions. We then summarize data on the efficacy and safety profiles of the three PDE-5 inhibitors for the treatment of ED in the general population, in patients with diabetes mellitus and in men that have undergone bilateral nerve-sparing retropubic radical prostatectomy.
Briganti
Alberto
A
Department of Urology at Università Vita Salute San Raffaele, Milan, Italy.
Salonia
Andrea
A
Gallina
Andrea
A
Saccà
Antonino
A
Montorsi
Piero
P
Rigatti
Patrizio
P
Montorsi
Francesco
F
D015106:3',5'-Cyclic-GMP Phosphodiesterases; D000284:Administration, Oral; D002243:Carbolines / Q000008:administration & dosage / Q000494:pharmacology; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage* / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases; D010879:Piperazines / Q000008:administration & dosage / Q000494:pharmacology; D011687:Purines; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000008:administration & dosage / Q000494:pharmacology; D000068581:Tadalafil; D014227:Triazines / Q000008:administration & dosage / Q000494:pharmacology; D000069058:Vardenafil Dihydrochloride
D002243:Carbolines; D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride; D000068581:Tadalafil; D000068677:Sildenafil Citrate; D010727:Phosphoric Diester Hydrolases; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; C517381:PDE5A protein, human