title: Differences in side-effect duration and related bother levels between phosphodiesterase type 5 inhibitors.
abstract: OBJECTIVE
  To assess whether the longer half-life of tadalafil is associated with longer lasting or more severe side-effects than the other phosphodiesterase type 5 inhibitors (PDE-5Is), as clinical trials have shown that the efficacy and safety of the three available are similar, but tadalafil has a half-life four times longer than the other two drugs.
  
  
  METHODS
  Treatment-naive men beginning PDE5-I therapy were recruited from a specialist clinic. Data on the type and duration of drug-associated side-effects were collected prospectively. Levels of bother were assessed with a visual analogue scale (VAS). Differences in type, duration and bother of side-effect were compared between drugs.
  
  
  RESULTS
  In all, 409 men provided data; there were no differences between drugs in the proportion of men responding, or the overall prevalence of side-effects. The mean duration of side-effects with tadalafil was 14.9 h, compared to 3.9 and 7.7 h for sildenafil and vardenafil. Of men taking tadalafil, 30% had side-effects lasting >12 h. There were no differences in mean VAS scores between the drugs. Individual side-effects caused similar levels of bother, except for facial flushing, which was less bothersome.
  
  
  CONCLUSIONS
  Men taking tadalafil are at risk of prolonged side-effects, although levels of bother associated with these side-effects are not significantly greater than those seen with short-acting PDE5-Is.
authors.affiliation: Department of Urology, York District Hospital, York, UK.
authors.forename: Joby
authors.initials: J
authors.lastname: Taylor
authors.forename: Omer B
authors.initials: OB
authors.lastname: Baldo
authors.forename: Anne
authors.initials: A
authors.lastname: Storey
authors.forename: Jon
authors.initials: J
authors.lastname: Cartledge
authors.forename: Ian
authors.initials: I
authors.lastname: Eardley
mesh_terms: D002243:Carbolines / Q000009:adverse effects / Q000627:therapeutic use; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006801:Humans; D007093:Imidazoles / Q000009:adverse effects / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D010726:Phosphodiesterase Inhibitors / Q000009:adverse effects* / Q000627:therapeutic use; D010879:Piperazines / Q000009:adverse effects / Q000627:therapeutic use; D011446:Prospective Studies; D011687:Purines / Q000009:adverse effects / Q000627:therapeutic use; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000009:adverse effects / Q000627:therapeutic use; D011795:Surveys and Questionnaires; D000068581:Tadalafil; D013997:Time Factors; D014227:Triazines / Q000009:adverse effects / Q000627:therapeutic use; D000069058:Vardenafil Dihydrochloride
chemical_list: D002243:Carbolines; D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride; D000068581:Tadalafil; D000068677:Sildenafil Citrate