title: Tadalafil has no detrimental effect on human spermatogenesis or reproductive hormones.
abstract: OBJECTIVE
  We assessed the effects on spermatogenesis of placebo vs 10 or 20 mg tadalafil administered daily for 6 months to healthy men and men with mild erectile dysfunction.
  
  
  METHODS
  In 2 studies 421 healthy men or men with mild erectile dysfunction who were 45 years or older and met semen criteria derived from WHO reference values were randomized to 6 months of treatment with placebo (101) or 10 mg tadalafil (103), or to placebo (106) or 20 mg tadalafil (111). Semen samples and serum for reproductive hormones (testosterone, luteinizing hormone and follicle-stimulating hormone) were collected at baseline, after 3 months and at the end of treatment.
  
  
  RESULTS
  Tadalafil had no adverse effects on spermatogenesis, as assessed by sperm concentration, sperm count per ejaculate, percent sperm motility, normal morphology or serum reproductive hormones. Tadalafil was well tolerated. Common adverse events were headache, dyspepsia and back pain.
  
  
  CONCLUSIONS
  Chronic daily administration of tadalafil at doses of 10 and 20 mg for 6 months had no adverse effects on spermatogenesis or on reproductive hormones in men older than 45 years.
authors.affiliation: Department of Urology SL-42, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA. whellst@tulane.edu
authors.forename: Wayne J G
authors.initials: WJ
authors.lastname: Hellstrom
authors.forename: James W
authors.initials: JW
authors.lastname: Overstreet
authors.forename: Albert
authors.initials: A
authors.lastname: Yu
authors.forename: Khalil
authors.initials: K
authors.lastname: Saikali
authors.forename: Wei
authors.initials: W
authors.lastname: Shen
authors.forename: Charles M
authors.initials: CM
authors.lastname: Beasley
authors.forename: Vish S
authors.initials: VS
authors.lastname: Watkins
mesh_terms: D015106:3',5'-Cyclic-GMP Phosphodiesterases; D002243:Carbolines / Q000008:administration & dosage / Q000494:pharmacology*; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D005640:Follicle Stimulating Hormone / Q000097:blood; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D007986:Luteinizing Hormone; D008297:Male; D008875:Middle Aged; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D010727:Phosphoric Diester Hydrolases; D012661:Semen / Q000187:drug effects; D013081:Sperm Motility / Q000187:drug effects; D013091:Spermatogenesis / Q000187:drug effects*; D000068581:Tadalafil; D013739:Testosterone / Q000097:blood
chemical_list: D002243:Carbolines; D012739:Gonadal Steroid Hormones; D010726:Phosphodiesterase Inhibitors; D013739:Testosterone; D000068581:Tadalafil; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D010727:Phosphoric Diester Hydrolases; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; C517381:PDE5A protein, human