title: Testosterone implants in women: pharmacological dosing for a physiologic effect.
abstract: OBJECTIVE
  The objectives of this study were to determine therapeutic serum testosterone (T) levels/ranges and inter-individual variance in women treated with subcutaneous T implants.
  
  
  METHODS
  In study group 1, T levels were measured at two separate time intervals in pre- and post-menopausal women treated with subcutaneous T for symptoms of androgen deficiency: (i) four weeks after pellet insertion, and (ii) when symptoms of androgen deficiency returned. In a separate pharmacokinetic study (study group 2), 12 previously untreated postmenopausal women each received a 100mg T implant. Serum T levels were measured at baseline, 4 weeks and 16 weeks following T pellet implantation. In study 'group' 3, serial T levels were measured throughout a 26 h period in a treated patient.
  
  
  RESULTS
  In study group 1, serum T levels measured at 'week 4' (299.36±107.34 ng/dl, n=154), and when symptoms returned (171.43±73.01 ng/dl, n=261), were several-fold higher compared to levels of endogenous T. There was significant inter-individual variance in T levels at 'week 4' (CV 35.9%) and when symptoms returned (CV 42.6%). Even with identical dosing (study group 2), there was significant inter-individual variance in T levels at 'week 4' (CV 41.9%) and 'week 16' (CV 41.6%). In addition, there was significant intra-individual circadian variation (CV 25%).
  
  
  CONCLUSIONS
  Pharmacologic dosing of subcutaneous T, as evidenced by serum levels on therapy, is needed to produce a physiologic effect in female patients. Safety, tolerability and clinical response should guide therapy rather than a single T measurement, which is extremely variable and inherently unreliable.
authors.affiliation: Millennium Wellness Center, Dayton, OH 45458, USA. rglaser@woh.rr.com
authors.forename: Rebecca
authors.initials: R
authors.lastname: Glaser
authors.forename: Sophia
authors.initials: S
authors.lastname: Kalantaridou
authors.forename: Constantine
authors.initials: C
authors.lastname: Dimitrakakis
mesh_terms: D000728:Androgens / Q000008:administration & dosage* / Q000097:blood* / Q000493:pharmacokinetics; D004343:Drug Implants; D005260:Female; D006801:Humans; D017698:Postmenopause / Q000097:blood* / Q000187:drug effects; D017697:Premenopause / Q000097:blood* / Q000187:drug effects; D018709:Statistics, Nonparametric; D013739:Testosterone / Q000008:administration & dosage* / Q000097:blood* / Q000172:deficiency / Q000493:pharmacokinetics
chemical_list: D000728:Androgens; D004343:Drug Implants; D013739:Testosterone