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Phosphodiesterase Type-5 Inhibitors: A Critical Comparative Analysis

2004; Elsevier BV; Volume: 2; Issue: 2 Linguagem: Inglês

10.1016/j.euus.2004.03.007

1873-2038

Hartmut Porst,

Pharmacology and Obesity Treatment

All three PDE5 inhibitors are targeting the same site of action e.g. PDE5 and this is why a quite similar efficacy and safety profile could be expected and was finally proven in many controlled studies. The efficacy as assessed by the endpoint successful intercourse with maintenance of erection (SEP3) ranges between 65 and 75% in broad-spectrum ED populations with clearly lower success-rates of 40–50% in patients with involvement of the penile nerve supply such as diabetics or patients after pelvic surgery. Generally speaking the drug-related adverse events are principally comparable except visual disturbances being more frequently reported after sildenafil and back pain/myalgia more often occurring after tadalafil. Considering the pharmacokinetic profile tadalafil distinguishes itself from sildenafil and vardenafil by its long half-life (T1/2=17.5 h) resulting in the majority of patients in successful coitus attempts even after 112 days. As a rule of thumb the clinical efficacy of the respective PDE5 inhibitors corresponds pretty well to the 2.5–3-fold half-life time. In terms of onset of action as mirrored by the Tmax vardenafil has the shortest one (40 min) followed by vardenafil (60 min) and tadalafil (120 min) As efficacy and side-effects may be differently perceived in the same individual patient with each of the three PDE5 inhibitors it seems reasonable to grant the couples the opportunity to try all drugs sequentially.