Pharmacokinetics and dose finding of a potent aromatase inhibitor, aromasin (exemestane), in young males.
Author(s): Mauras N, Lima J, Patel D, Rini A, di Salle E, Kwok A, Lippe B
Affiliation(s): Nemours Children's Clinic and Research Programs, Jacksonville, Florida 32207, USA. nmuras@nemours.org
Publication date & source: 2003-12, J Clin Endocrinol Metab., 88(12):5951-6.
Publication type: Clinical Trial; Randomized Controlled Trial
Suppression of estrogen, via estrogen receptor or aromatase blockade, is being investigated in the treatment of different conditions. Exemestane (Aromasin) is a potent and selective irreversible aromatase inhibitor. To characterize its suppression of estrogen and its pharmacokinetic (PK) properties in males, healthy eugonadal subjects (14-26 yr of age) were recruited. In a cross-over study, 12 were randomly assigned to 25 and 50 mg exemestane daily, orally, for 10 d with a 14-d washout period. Blood was withdrawn before and 24 h after the last dose of each treatment period. A PK study was performed (n = 10) using a 25-mg dose. Exemestane suppressed plasma estradiol comparably with either dose [25 mg, 38% (P <or= 0.002); 50 mg, 32% (P <or= 0.008)], with a reciprocal increase in testosterone concentrations (60% and 56%; P <or= 0.003 for both). Plasma lipids and IGF-I concentrations were unaffected by treatment. The PK properties of the 25-mg dose showed the highest exemestane concentrations 1 h after administration, indicating rapid absorption. The terminal half-life was 8.9 h. Maximal estradiol suppression of 62 +/- 14% was observed at 12 h. The drug was well tolerated. In conclusion, exemestane is a potent aromatase inhibitor in men and an alternative to the choice of available inhibitors. Long-term efficacy and safety will need further study.
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