Dr. Berry on the Differences Between LHRH Antagonists and Agonists

William R. Berry, MD, medical oncologist, Duke University, talks about the differences between luteinizing hormone-releasing hormone (LHRH) antagonists and agonists.

Agonists and antagonists are similar drugs because they both indicate for the decrease in the testicle's testosterone production. However, agonists and antagonists differ in how they work through the pituitary gland.

When agonists bind to the pituitary gland's LHRH receptor, the receptor's initial stimulation results in the excess release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), causing early testosterone release in the testicles typically within the first 10 days after therapy. Antagonists block the receptor from the start, resulting in the immediate decrease in FSH and LH secretion, causing an instant decrease in the testicle's testosterone production.

The FDA-approved agonist drugs include leuprolide acetate (Eligard) and goserelin (Zoladex), and the only FDA-approved antagonist is degarelix (Firmagon).