Rechallenge prior sildenafil nonresponders

Abstract

To assess inappropriate use as a cause of sildenafil (Viagra™) failure and the feasibility of successfully rechallenging nonresponding patients, a total of 60 consecutive erectile dysfunction (ED) patients who first presented to our hospital and claimed poor response to sildenafil were enrolled into the study. The International Index of Erectile Function-5 (IIEF-5) was used to evaluate their baseline ED status and a self-administered sildenafil-use questionnaire composed of nine questions (SUQ-9) to assess how they had used sildenafil. A total of 44 subjects consent to rechallenge with sildenafil and were given thorough instruction based on individual answers to SUQ-9 and four doses of sildenafil 100 mg. After a 4-week follow-up, end point efficacy of rechallenge was evaluated using the IIEF-5 and the global assessment question (GAQ), ‘After the treatment, did you have successful sexual intercourse?’ Of the 60 subjects, 44 (77.3%) had one or more areas of major suboptimal use of sildenafil: 18 (30.0%) did not know that sexual stimulation was necessary for sildenafil to work, 36 (60.0%) attempted to use sildenafil less than four times, and 27 (45.0%) took a maximal dose less than 100 mg. Of the 44 patients undergoing sildenafil rechallenge, 34 (77.3%) completed the follow-up, while seven (15.9%) received only GAQ assessment by telephone interview and three (6.8%) were lost to follow-up. The total follow-up rate was 93.2% (41/44). Based on answers to the GAQ, the response rate to rechallenge was 58.5% (24/41). The mean improvement in the IIEF-5 score was 8.4±5.5 in responders (P <0.05). With individualized thorough instruction based on answers to SUQ-9 and scheduled follow-up, a high success rate was achieved by rechallenge with sildenafil in prior failures. The efficacy of sildenafil could be improved to a great extent by adequate education of patients and continuing medical education given to primary-care physicians.