Decreased Anticoagulant Tolerance During Methandrostenolone Therapy

Administration of methandrostenolont (δ¹ -17α-methyltestosterone) in a dosage of 10 mg a day to patients on maintenance therapy with warfarin sodium or phenylindanedione was found to produce, within two weeks, a significant decrease in the anticoagulant requirement.

The response to a single dose of 20 mg of warfarin sodium in healthy subjects was found to be increased when the test subjects had taken methandrostenolone 10 mg daily for 10 days. Liver function studies in healthy subjects, who received methandrostenolone in a similar dosage for 10 days, revealed a significant increase of the α₂-globulin fraction, a significant decrease of alkaline-phosphatase activity, and a significant decrease of bromsulfalein clearance.