title: The effect of letrozole on bone age progression, predicted adult height, and adrenal gland function.
abstract: A common problem in pediatric endocrinology is limited growth potential resulting from advancing skeletal maturation. We determined the efficacy of letrozole, an aromatase inhibitor, on delaying bone age advancement in adolescent males with limited growth potential. Twenty-four patients met the study inclusion criteria. Six patients treated with androgen were analyzed separately. Low-dose ACTH stimulation tests were performed to ascertain the effect of letrozole on adrenal gland function. In patients not on androgen, bone age progression decelerated from 1.51+/-0.57 (deltabone age/deltachronological age) before treatment to 0.68+/-0.66 on therapy (mean duration 12.4 months; p <0.0005). Predicted adult height standard deviation scores (SDS) increased from -1.41+/-0.54 to -0.64+/-0.65 on treatment (p <0.0005). Similar results were noted in androgen-treated patients. Approximately one-fourth of patients displayed subnormal responsiveness to ACTH. In summary: 1) letrozole decelerates skeletal maturation, resulting in significant increases in predicted adult height, and 2) letrozole causes mild adrenal suppression.
authors.affiliation: Section of Endocrinology, Department of Pediatrics, Children's Mercy Hospitals, Kansas City, MO 64108, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Karmazin
authors.forename: Wayne V
authors.initials: WV
authors.lastname: Moore
authors.forename: Jadranka
authors.initials: J
authors.lastname: Popovic
authors.forename: Jill D
authors.initials: JD
authors.lastname: Jacobson
mesh_terms: D000293:Adolescent; D000311:Adrenal Glands / Q000187:drug effects* / Q000502:physiology*; D000324:Adrenocorticotropic Hormone; D047072:Aromatase Inhibitors / Q000009:adverse effects* / Q000494:pharmacology*; D001827:Body Height; D001846:Bone Development / Q000187:drug effects*; D001842:Bone and Bones / Q000187:drug effects*; D002648:Child; D002675:Child, Preschool; D006130:Growth Disorders / Q000188:drug therapy*; D006801:Humans; D000077289:Letrozole; D008297:Male; D009570:Nitriles / Q000009:adverse effects* / Q000494:pharmacology*; D016896:Treatment Outcome; D014230:Triazoles / Q000009:adverse effects* / Q000494:pharmacology*
chemical_list: D047072:Aromatase Inhibitors; D009570:Nitriles; D014230:Triazoles; D000077289:Letrozole; D000324:Adrenocorticotropic Hormone