title: Sildenafil failures may be due to inadequate patient instructions and follow-up: a study on 100 non-responders.
abstract: OBJECTIVE
  The objective of this study was to identify factors that affect efficacy response rate to sildenafil in the clinical practice.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Urology and Center for Sexual and Reproductive Health, Aristotle University of Thessaloniki, Thessaloniki, Greece. hatzichr@med.auth.gr
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Hatzichristou
authors.forename: Kyriakos
authors.initials: K
authors.lastname: Moysidis
authors.forename: Apostolos
authors.initials: A
authors.lastname: Apostolidis
authors.forename: Athanasios
authors.initials: A
authors.lastname: Bekos
authors.forename: Vasilios
authors.initials: V
authors.lastname: Tzortzis
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Hatzimouratidis
authors.forename: Evangelos
authors.initials: E
authors.lastname: Ioannidis
mesh_terms: D000328:Adult; D000368:Aged; D007172:Erectile Dysfunction / Q000188:drug therapy*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010353:Patient Education as Topic / Q000592:standards*; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage* / Q000627:therapeutic use; D010879:Piperazines / Q000008:administration & dosage* / Q000627:therapeutic use; D011687:Purines; D000068677:Sildenafil Citrate; D013450:Sulfones; D017211:Treatment Failure
chemical_list: D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate