title: Serum concentrations of enclomiphene and zuclomiphene across consecutive cycles of clomiphene citrate therapy in anovulatory infertile women.
abstract: OBJECTIVE
  To determine the serum concentrations of enclomiphene and zuclomiphene across consecutive cycles of clomiphene citrate treatment in anovulatory infertile women.
  
  
  METHODS
  Prospective cohort.
  
  
  METHODS
  Tertiary institutional infertility clinic.
  
  
  METHODS
  Fourteen consenting anovulatory infertile women receiving standardized, cyclic, incremental treatment with clomiphene citrate for ovulation induction.
  
  
  METHODS
  Clomiphene citrate treatment (50-150 mg/d, cycle days 5-9), titrated to the minimum effective ovulation-inducing dose, was administered for three to six total cycles. Blood samples were obtained on cycle days 3 and 10 in each treatment cycle.
  
  
  METHODS
  Serum concentrations of enclomiphene and zuclomiphene.
  
  
  RESULTS
  Cycle day 3 zuclomiphene levels were below assay limits in all initial cycles, increased progressively across three consecutive cycles, and thereafter plateaued. Cycle day 3 enclomiphene concentrations were uniformly undetectable. Cycle day 10 enclomiphene levels increased with dose administered, but these observations were not statistically significant.
  
  
  CONCLUSIONS
  Clomiphene citrate induction of ovulation results in an isomer-specific systemic accumulation of zuclomiphene across consecutive cycles of treatment. The combined maximum concentration of enclomiphene and zuclomiphene attained in practice approximates 100 nmol/L and is generally well below levels previously demonstrated to have adverse effects in vitro.
authors: Department of Obstetrics and Gynecology, The University of Texas Medical Branch at Galveston, 77555-0587, USA. slyoung@utmb.edu
authors: S L
authors: SL
authors: Young
authors: M S
authors: MS
authors: Opsahl
authors: M A
authors: MA
authors: Fritz
mesh_terms: D000328:Adult; D000858:Anovulation / Q000188:drug therapy*; D002996:Clomiphene / Q000097:blood* / Q000493:pharmacokinetics* / Q000627:therapeutic use; D015331:Cohort Studies; D064695:Enclomiphene; D005260:Female; D005300:Fertility Agents, Female / Q000493:pharmacokinetics* / Q000627:therapeutic use; D006801:Humans; D007247:Infertility, Female / Q000188:drug therapy*; D010062:Ovulation Induction; D011446:Prospective Studies
chemical_list: D005300:Fertility Agents, Female; D002996:Clomiphene; D064695:Enclomiphene