Aminoglutethimide administered concomitantly with high doses of MPA may significantly depress the serum concentrations of medroxyprogesterone acetate. Users of high-dose MPA should be warned of the possibility of decreased efficacy with the use of aminoglutethimide.
MPA is metabolized in-vitro primarily by hydroxylation via CYP3A4. Specific drug-drug interaction studies evaluating the clinical effects with CYP3A4 inducers or inhibitors on MPA have not been conducted and therefore the clinical effects of CYP3A4 inducers or inhibitors are unknown. (10 mg: Inducers and/or inhibitors of CYP3A4 may affect the metabolism of MPA.)