title: Erectile response to vardenafil in men with a history of nonresponse to sildenafil: a time-from-dosing descriptive analysis.
abstract: BACKGROUND
  The efficacy and tolerability of vardenafil hydrochloride in men with erectile dysfunction (ED) and a history of nonresponse to sildenafil citrate have previously been reported.
  
  
  OBJECTIVE
  The aim of this descriptive analysis was to assess the efficacy and tolerability of vardenafil at various times after dosing in men with ED and a history of nonresponse to sildenafil and who chose to attempt sexual intercourse between 0.25 and 6 hours after dosing with vardenafil.
  
  
  METHODS
  This analysis used data from a previously published 12-week, prospective, randomized, double-blind, flexible-dose, placebo-controlled study conducted at 41 hospitals and outpatient clinics across Australia, Europe, Asia, and North America. In that study, men with ED and sildenafil nonresponse, defined using 6 rigorous criteria (including nonresponse to the highest recommended dose, 100 mg/d) were assigned to receive vardenafil 10 mg or placebo QD. At study weeks 4 and 8, patients in both groups were given the option to maintain the 10-mg/d dose, or have the dose titrated to 5 or 20 mg/d. The present analysis used data from patient diaries completed daily, which included information concerning attempts at sexual intercourse, time from dosing to attempt, penetration, and maintenance of erection sufficient for successful intercourse. At week 12, diary data were categorized into time intervals (in hours) after dosing. For each interval, the per-patient success rate was based on the total number of attempts made in that interval. Comparative statistics were not performed on the time-interval analysis. Tolerability was monitored throughout the study. Data concerning the primary end point were reported previously.
  
  
  RESULTS
  A total of 463 men were enrolled, of whom 457 were included in the safety analysis (vardenafil, n = 231; placebo, n = 226) and 454 in the intent-to-treat analysis (vardenafil, n = 229; placebo, n = 225; mean age, 60.1 vs 59.0 years; mean body mass index, 28.7 vs 28.0 kg/m2). Six patients were excluded from the safety analysis (2 patients did not use study medication [placebo group], postbaseline safety data unavailable in 4 patients [2 in each study group]). Men receiving vardenafil had numerically greater penetration and completion success rates compared with those receiving placebo at all time intervals. Penetration success rates were numerically higher with vardenafil compared with placebo as early as within 0.25 hour after dosing (62% vs 30%); efficacy continued beyond 6 hours after dosing in 77% and 50% of patients, respectively. Similarly, vardenafil-treated patients had numerically greater completion success rates compared with those receiving placebo at 0.25 hour (53% vs 12%) and beyond 6 hours after dosing (70% vs 24%). The most common drug-related adverse events in the vardenafil and placebo groups were flushing (7% vs 1%), headache (6% vs 2%), and nasal congestion (5% vs <1%).
  
  
  CONCLUSIONS
  This descriptive analysis suggests that erection sufficient for penetration and intercourse completion was achieved within 0.25 hour and lasted for >6 hours after dosing with vardenafil 10 mg in these men with mostly moderate to severe ED and a history of nonresponse to sildenafil and who chose to make attempts during those intervals. The drug was generally well tolerated.
authors.affiliation: Center for Sexual and Reproductive Health, Aristotle University of Thessaloniki, Thessaloniki, Greece. hatzichr@med.auth.gr
authors.forename: Dimitrios G
authors.initials: DG
authors.lastname: Hatzichristou
authors.forename: Philip
authors.initials: P
authors.lastname: Aliotta
authors.forename: Stephen
authors.initials: S
authors.lastname: Auerbach
authors.forename: Jack
authors.initials: J
authors.lastname: Barkin
authors.forename: Douglas
authors.initials: D
authors.lastname: Lording
authors.forename: Myron
authors.initials: M
authors.lastname: Murdock
authors.forename: H Jeffrey
authors.initials: HJ
authors.lastname: Wilkins
authors.forename: Trish A
authors.initials: TA
authors.lastname: McBride
authors.forename: Michael W
authors.initials: MW
authors.lastname: Colopy
authors.forename: Culley C
authors.initials: CC
authors.lastname: Carson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004311:Double-Blind Method; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D010410:Penile Erection / Q000187:drug effects*; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D010879:Piperazines / Q000008:administration & dosage / Q000627:therapeutic use*; D011687:Purines; D016032:Randomized Controlled Trials as Topic; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000008:administration & dosage / Q000627:therapeutic use; D011795:Surveys and Questionnaires; D013997:Time Factors; D014227:Triazines / Q000008:administration & dosage / Q000627:therapeutic use; D000069058:Vardenafil Dihydrochloride
chemical_list: D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride; D000068677:Sildenafil Citrate