title: Sildenafil citrate (Viagra) impairs fertilization and early embryo development in mice.
abstract: OBJECTIVE
  To determine the effects of sildenafil citrate, a cyclic monophosphate-specific type 5 phosphodiesterase inhibitor known to affect sperm function, on fertilization and early embryo cleavage.
  
  
  METHODS
  This acute mammal study included male and female mice assigned randomly, the females sacrificed after mating and their oocytes/embryos evaluated at four time periods after treatment.
  
  
  METHODS
  Academic research environment.
  
  
  METHODS
  Male and female CBAB(6) mice.
  
  
  METHODS
  Female mice were injected intraperitoneally with 5 IU gonadotropin (hCG) to stimulate follicular growth and induce ovulation. They were each caged with a male that had been gavaged with sildenafil citrate (0.06 mg/0.05 mL) and allowed to mate. After 12, 36, 60, and 84 h, females were killed, their oviducts were dissected out, and retrieved embryos were assessed for blastomere number and quality.
  
  
  METHODS
  Fertilization rates and numbers of embryos were evaluated after treatment.
  
  
  RESULTS
  Fertilization rates (day 1) were markedly reduced (-33%) in matings where the male had taken sildenafil citrate. Over days 2-4, the numbers of embryos developing in the treated group were significantly fewer than in the control group. There was also a trend for impaired cleavage rates within those embryos, although this did not reach significance.
  
  
  CONCLUSIONS
  The impairments to fertility caused by sildenafil citrate have important implications for infertility centers and for couples who are using this drug precoitally while attempting to conceive.
authors.affiliation: Obstetrics and Gynaecology, Institute of Clinical Science, School of Medicine, Belfast, United Kingdom.
authors.forename: David R J
authors.initials: DR
authors.lastname: Glenn
authors.forename: Neil
authors.initials: N
authors.lastname: McClure
authors.forename: S Louise
authors.initials: SL
authors.lastname: Cosby
authors.forename: Michael
authors.initials: M
authors.lastname: Stevenson
authors.forename: Sheena E M
authors.initials: SE
authors.lastname: Lewis
mesh_terms: D000818:Animals; D001757:Blastomeres / Q000187:drug effects*; D002970:Cleavage Stage, Ovum / Q000187:drug effects*; D003307:Copulation; D047108:Embryonic Development / Q000187:drug effects; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D008297:Male; D051379:Mice; D010062:Ovulation Induction; D010726:Phosphodiesterase Inhibitors / Q000009:adverse effects*; D010879:Piperazines / Q000009:adverse effects*; D011247:Pregnancy; D011687:Purines / Q000009:adverse effects; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000009:adverse effects*; D013997:Time Factors
chemical_list: D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate