Sildenafil failures may be due to inadequate patient instructions and follow-up: a study on 100 non-responders

The objective of this study was to identify factors that affect efficacy response rate to sildenafil in the clinical practice.

The study comprised 100 consecutive sildenafil non-responders. Mean patient age was 59+/-14.4 years and mean duration of ED 5.5+/-6.4 years. All patients underwent detailed medical and sexual history and completed the IIEF and a questionnaire regarding the previous use of sildenafil. When inadequate instructions were reported, information on the appropriate use of sildenafil was given and patients were asked to use at least 4 tablets at home. Pharmacologic efficacy was re-evaluated in a scheduled follow-up visit.

Mean Erectile Function Domain (ED) of the IIEF score was 14+/-9.9. In 56 patients inappropriate use of sildenafil was recognized; 45 had never used the highest recommended dose (100 mg), 32 had taken the pill with a full stomach right after a meal, 22 had taken the pill just before the initiation of sexual activity and 12 were not aware that sexual stimulation was mandatory to achieve an erection. Furthermore, 8 patients had tried the 100mg dose, despite the presence of factors associated with sildenafil clearance reduction (renal insufficiency, cimetidine treatment). Only 34 patients reported that their physician had scheduled a follow-up visit. Following adequate dose titration and time adjustment, 31 patients responded to sildenafil; 10 patients used the 50 mg dose and 21 the 100 mg. Second and third-line treatment options were offered to the rest of the patients.

ED patients may receive inadequate instructions with their prescriptions. Response rate to sildenafil may be maximized after receiving appropriate dose titration and instructions on administration. ED should be treated in the same way as other chronic conditions; follow-up is necessary to evaluate the appropriate application and pharmacologic efficacy of the proposed treatment.