Medrysone (INN, USAN) (brand names HMS, Medrocort, others; former developmental code name NSC-63278), also known as hydroxymethylprogesterone, methylhydroxyprogesterone, or hydroxymesterone, as well as 6α-methyl-11β-hydroxyprogesterone or 6α-methyl-11β-hydroxypregn-4-ene-3,20-dione, is a synthetic glucocorticoid that is or has been used in the treatment of inflammatory eye diseases.

[1][2][3] It has been discontinued in the United States.

[4] Although it is very similar in structure to progesterone,[5] neither progestogenic nor androgenic activity has been demonstrated for or attributed to medrysone.

[6][7][8] In 2021, medrysone was one of the 12 compounds identified in sludge samples taken from 12 wastewater treatment plants in California that were associated with estrogenic activity in in vitro.

[9] This article about a steroid is a stub.