title: Sildenafil citrate as a phosphodiesterase inhibitor has an antioxidant effect in the blood of men.
abstract: OBJECTIVE
  Sildenafil citrate enhances the action of nitric oxide by preventing the hydrolysis of cGMP, and is widely used to treat erectile dysfunction. We investigated the effects of sildenafil citrate administration on lipid peroxidation and antioxidant redox enzymes in blood of healthy men.
  
  
  METHODS
  Thirty healthy male subjects were divided equally into two groups. The first group was used as the control. A single dose of sildenafil citrate was administrated orally to subjects constituting the second group. Blood samples were obtained at 0, 2, 6 and 24 h after intake of the single dose of 100 mg sildenafil citrate or placebo.
  
  
  CONCLUSIONS
  The dose of sildenafil citrate resulted in significant increase in the erythrocyte superoxide dismutase and catalase activities at 6 and 24 h. Plasma lipid peroxidation levels decreased slightly. There was no statistical difference in erythrocyte glutathione peroxidase activity between the placebo and sildenafil citrate groups.
  
  
  CONCLUSIONS
  Treatment of blood with 100 mg sildenafil citrate has protective effects on oxidative stress by inhibiting free radical formation and by supporting antioxidant redox systems.
authors.affiliation: Department of Urology, Medical Faculty, Suleyman Demirel University, Isparta, Turkey.
authors.forename: H
authors.initials: H
authors.lastname: Perk
authors.forename: A
authors.initials: A
authors.lastname: Armagan
authors.forename: M
authors.initials: M
authors.lastname: Naziroğlu
authors.forename: S
authors.initials: S
authors.lastname: Soyupek
authors.forename: M B
authors.initials: MB
authors.lastname: Hoscan
authors.forename: R
authors.initials: R
authors.lastname: Sütcü
authors.forename: A
authors.initials: A
authors.lastname: Ozorak
authors.forename: N
authors.initials: N
authors.lastname: Delibas
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000494:pharmacology*; D002374:Catalase / Q000187:drug effects / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors; D055815:Young Adult
chemical_list: D000975:Antioxidants; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D009569:Nitric Oxide; D000068677:Sildenafil Citrate; D002374:Catalase; D013482:Superoxide Dismutase; D006152:Cyclic GMP