Over a dose selection of 2.5 to 20 mg, tadalafil exposure (AUC) increases proportionally with dose in healthy subjects. Steady-state plasma concentrations are attained within 5 days of once daily dosing and exposure is roughly 1.6-fold higher than after having a single dose. Mean tadalafil concentrations measured following your administration of a single oral dose of 20 mg and single as soon as daily multiple doses of 5 mg, from a separate study, (see Figure 4) to healthy male subjects are depicted in Figure 4.