Sildenafil citrate tablets (VIAGRA; Pfizer Inc) have been used since 1998 as an oral therapy for the treatment of erectile dysfunction. However, in some cases, patients may have difficulty in swallowing tablets, and the need to use water to aid in the oral administration of the tablets has the potential to interrupt the sexual encounter, reduce spontaneity, and therefore decrease the quality of the experience. Two oral soluble film (OSF) formulations of sildenafil were developed using MonoSol Rx's proprietary PharmFilm technology. Both films were formulated to dissolve rapidly on the tongue, thereby releasing the drug into the oral cavity, whereupon it is swallowed without the use of water. From a patient perspective, it is anticipated that the film formulations of sildenafil citrate will provide a more compliant and discreet dosage form. The purpose of this clinical study was to compare the bioequivalence of the 2 sildenafil OSF 100 mg formulations (MonoSol Rx, LLC) with the sildenafil citrate 100 mg tablets. The design was a single-dose, randomized, open-label, 3-period, 6-sequence, 3-treatment, single-center, crossover study conducted in 18 healthy, nonsmoking male volunteers under fasting conditions, with each treatment period separated by a 7-day washout period. Plasma sildenafil concentrations were measured predose and then periodically to 24 hours after dosing. The 90% confidence intervals for plasma sildenafil AUC0–t, AUC0–∞, and Cmax for both sildenafil OSF formulations as compared with sildenafil citrate tablets were all within the 80%–125% range, indicating bioequivalence of both film formulations to sildenafil citrate tablets. Overall, the demonstrated bioequivalence coupled with the performance advantages of an OSF dosage form (ie, rapid dissolution in the mouth, can be taken without water, and can be dosed discreetly) suggest that the sildenafil OSF may provide an attractive alternative to sildenafil citrate oral tablets.