title: Daily administration of phosphodiesterase type 5 inhibitors for urological and nonurological indications.
abstract: OBJECTIVE
  Although the discovery of phosphodiesterases (PDEs) was made soon after the identification of cyclic adenosine monophosphate nearly half a century ago, their true importance in medicine has taken many decades to be realised. The recognition of the important role PDE enzymes play and the impact of altering intracellular cyclic nucleotide levels became significant for most urologists and clinicians in the early 1990s with the discovery of sildenafil, a PDE5 inhibitor (PDE5-I). Once approved around the world, on-demand use of PDE5-Is became the gold standard. Recently, the potential beneficial effects of PDE5-Is on the pulmonary, vascular, and other systems has led to examination of alternative dosing regimens. In this review, we have synthesised the available published peer-reviewed literature to provide a critical contemporary view of evolving indications for PDE5-Is and how alternative dosing regimens may impact on sexual and other functions.
  
  
  METHODS
  MEDLINE search of all peer-reviewed English literature for the period 1990-2007.
  
  
  RESULTS
  The plethora of articles detailing potential uses of PDE5-I in multiple fields of medicine was uncovered. Use of alternative dosing regimens shows great promise across a number of clinical indications, including post-radical retropubic prostatectomy, pulmonary hypertension, endothelial dysfunction, and salvage of on-demand PDE5-I nonresponders.
  
  
  CONCLUSIONS
  Use of PDE5-I on a daily basis may evolve into a major form of drug administration both for men with erectile dysfunction and for those with a myriad of other conditions shown to benefit from this approach.
authors.affiliation: Department of Surgery, Division of Urology, University of Ottawa, Ottawa, Canada.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Bella
authors.forename: Ling X
authors.initials: LX
authors.lastname: Deyoung
authors.forename: Mussa
authors.initials: M
authors.lastname: Al-Numi
authors.forename: Gerald B
authors.initials: GB
authors.lastname: Brock
mesh_terms: D002316:Cardiotonic Agents / Q000627:therapeutic use; D007172:Erectile Dysfunction / Q000188:drug therapy; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy; D008297:Male; D058986:Phosphodiesterase 5 Inhibitors; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D016879:Salvage Therapy; D014570:Urologic Diseases / Q000188:drug therapy
chemical_list: D002316:Cardiotonic Agents; D058986:Phosphodiesterase 5 Inhibitors; D010726:Phosphodiesterase Inhibitors