title: Repeated intramuscular injections of testosterone undecanoate for substitution therapy in hypogonadal men.
abstract: OBJECTIVE
  To investigate the suitability of intramuscular testosterone undecanoate (TU) injections for substitution therapy in hypogonadal men.
  
  
  METHODS
  Clinical, open-label, non-randomized trial of 13 hypogonadal men receiving 4 intramuscular injections of 1000 mg TU in 4-ml castor oil at 6-week intervals. General wellbeing, sexual parameters, clinical chemistry, hormone levels, prostate size and prostate-specific antigen (PSA) were evaluated over 24 weeks and compared with baseline values.
  
  
  RESULTS
  Testosterone serum levels were never found below the lower limit of normal and only briefly after the 3rd and 4th injection above the upper limit of normal, while peak and trough values increased over the 24-week observation period. Oestradiol and dihydrotestosterone followed this pattern, not exceeding the normal limits. No serious side-effects were noted. Slight increases in body weight, haemoglobin, haematocrit, prostate volume and PSA, suppression of gonadotrophins as well as increased ejaculation frequency occurred as signs of adequate testosterone substitution.
  
  
  CONCLUSIONS
  Testosterone undecanoate is well tolerated by the patients. The injection intervals can be extended even beyond the 6-week periods chosen in the present study. Altogether, intramuscular testosterone undecanoate appears to be well suited for long-term substitution therapy in hypogonadism and hormonal male contraception.
authors.affiliation: Institute of Reproductive Medicine of the University, Münster, Germany. nieschl@uni-muenster.de
authors.forename: E
authors.initials: E
authors.lastname: Nieschlag
authors.forename: D
authors.initials: D
authors.lastname: Büchter
authors.forename: S
authors.initials: S
authors.lastname: Von Eckardstein
authors.forename: K
authors.initials: K
authors.lastname: Abshagen
authors.forename: M
authors.initials: M
authors.lastname: Simoni
authors.forename: H M
authors.initials: HM
authors.lastname: Behre
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001835:Body Weight / Q000187:drug effects; D013196:Dihydrotestosterone / Q000097:blood; D004542:Ejaculation / Q000187:drug effects; D004958:Estradiol / Q000097:blood; D020249:Hormone Replacement Therapy; D006801:Humans; D007006:Hypogonadism / Q000097:blood / Q000188:drug therapy*; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013739:Testosterone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use
chemical_list: D012738:Sex Hormone-Binding Globulin; D013196:Dihydrotestosterone; D013739:Testosterone; D004958:Estradiol; C010792:testosterone undecanoate