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  Testolactone (Teslac)
Author: Donna Karasic, PharmD Last modified: February 24, 2002


  • Gynecomastia in males (non-FDA approved use)
  • Breast cancer


  • Gynecomastia: 450mg/day
  • Breast Cancer: 250mg four times daily (1gm/day); may be increased to 2gm/day in patients that do not respond to 1gm/day


  • Testolactone is absorbed from the GI tract
  • Testolactone is metabolized by the liver to several derivatives
  • Renal excretion is 94%


  • Increased blood pressure
  • Nausea, vomiting, anorexia
  • Maculopapular erythema
  • Paresthesia, aches, edema of the extremities
  • Glossitis
  • Alopecia alone and in association with nail growth disturbances


  • Men with breast cancer
  • Hypersensitivity to testolactone


  • oral anticoagulants


  • 50mg tablets


  • Testolactone is a synthetic testosterone derivative without significant androgen activity
  • Testolactone inhibits steroid aromatase activity, blocking the production of estradiol and estrone from androgen precursors such as testosterone and androstenedione
  • The enzymatic block provided by testolactone is transient and is usually limited to period of 3 months
  • It has been suggested that Testolactone may reduce estrone synthesis from adrenal androstenedione via noncompetitive, irreversible inhibition of A-ring reductase (aromatase)
  • When used in conjunction with oral anticoagulants, monitor and adjust anticoagulant dose
  • Monitor hepatic function
  • Monitor for edema (congestive heart failure or preexisting cardiac, renal, or hepatic disease)
  • Use caution with epilepsy, migraine, or any condition that may be aggravated by fluid retention
  • Use caution in patients receiving treatment for hypertension
  1. Hutchinson TA & Shahan DR (Eds) ;  Testolactone ;  MICROMEDEX Healthcare Series; MICROMEDEX, Greenwood Village, Colorado (edition expires 3-2002)

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