Unlike the SSRIs mentioned above, dapoxetine was developed specifically for treatment of PE and is the only SSRI approved for treatment of the condition. What sets dapoxetine apart from other SSRIs currently used off-label to treat PE is its pharmacokinetic profile. Briefly, the pharmacology of dapoxetine may be summarized as follows:
Dapoxetine is rapidly absorbed following oral administration, whereas other SSRIs take several days or even weeks to reach steady-state concentrations.
Peak plasma levels of dapoxetine are reached in approximately 1 hour following a dose of 30 mg or 60 mg
Dapoxetine is rapidly eliminated; its initial half-life is approximately 1.4 hours for both doses, compared with 21 hours to 4 days for other SSRIs
Dapoxetine has a terminal half-life of 18.7 hours for the 30 mg dose and 21.9 hours for the 60 mg dose
Even with multiple dosing, the pharmacokinetics of dapoxetine are unchanged, and it does not appear to accumulate significantly.
These pharmacokinetic characteristics make dapoxetine ideal for on-demand dosing, which reduces the probability of unwanted side effects. Previous Phase II studies identified the optimal dose to be 30 mg initially, with an increase to 60 mg (the maximum recommended dose) if required. Pharmacodynamic studies identified the optimal dose administration time to be 1–3 hours before sexual intercourse.