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 syntheticglucocorticoid that is or has been used in the treatment of inflammatoryeye 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]