Phosphodiesterase Type-5 Inhibitors: A Critical Comparative Analysis

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.