Purpose: The main purpose of this work was to investigate the effect of pummelo juice on the pharmacokinetics of sildenafil after oral administration.
Methods: This was a comparative, randomized, two-period, two-treatment, two-sequence, single dose, crossover study investigating the effect of pummelo juice on the pharmacokinetics of sildenafil citrate tablets (equivalent to 50 mg sildenafil) in healthy male participants under fasting conditions compared with water as a control. Six healthy normal adult males were administered 50 mg sildenafil with pummelo juice or water at two different periods in a crossover study.
Results: Study results showed that pummelo juice reduced the rate and extent of sildenafil bioavailability to around 60% [maximum plasma concentration (C(max)); from 212.44 ng/ml to 134.07 ng/ml, 90% confidence interval (90% CI) 44.70-89.11, and area under the plasma concentration time curve from zero to infinity (AUC(infinity)); from 564.51 ng.hr/ml to 336.87 ng.hr/ml, 90% CI 39.17-90.92]. This interaction was opposite to that expected and is speculated to be due to either an effect on transporters or a physicochemical interaction between sildenafil and some components of the juice.
Conclusion: Patients should be advised not to drink pummelo juice before or immediately after taking sildenafil.