High Quality Content by WIKIPEDIA articles! Premarin is the commercial name for a compound cream of vaginally administered estrogens, consisting primarily of conjugated estrogens. Isolated from mares` urine (PREgnant MARes` urINe), it is manufactured by Wyeth Pharmaceuticals (part of Pfizer since January 2009) and has been marketed since 1942. It is available in oral (0.3/ 0.45/ 0.625/ 0.9/ 1.25 mg), IV, and topical form.