PROMETRIUM® is bio-identical to progesterone, which means it is structurally identical to the naturally occurring progesterone in your body. As you can see below, the physical structures of progesterone and PROMETRIUM® are the same. There is no evidence that bio-identical hormones are safer or more effective than other progestogens.

Comparing progesterone and PROMETRIUM®
 

Unlike PROMETRIUM®, synthetic (man-made) progestins have chemical structures that are different from progesterone. In the image below, you can see how certain progestins are structurally different from your body’s natural progesterone.

The clinical significance of this difference has not been determined.

Comparing progesterone and progestins

†Provera® is a registered trademark of Pharmacia & Upjohn Company.
‡ Aygestin® is a registered trademark of Duramed Pharmaceuticals, Inc.

PATIENTS WHO ARE ALLERGIC TO PEANUTS SHOULD NOT USE PROMETRIUM® CAPSULES.[2]

PROMETRIUM® is contraindicated for patients with any of the following conditions: known hypersensitivity to any of the ingredients: undiagnosed abnormal genital bleeding; known, suspected, or history of cancer of the breast; active deep vein thrombosis, pulmonary embolism, or history of these conditions; active or recent (within the past year) arterial thromboembolic disease (e.g., stroke, myocardial infarction); liver dysfunction or disease; or known or suspected pregnancy.[2]

References:
1. AHFS Drug Information. Bethesda, Md: American Society of Health-System Pharmacists, Inc; 2000. 2. PROMETRIUM® [package insert]. Marietta, Ga: Solvay Pharmaceuticals, Inc.; 2004. 3. Provera® [package insert]. New York, NY: Pharmacia & Upjohn Co, a division of Pfizer Inc; 2004. 4. Aygestin® [package insert]. Pomona, NY: Duramed Pharmaceuticals, Inc, a subsidiary of Barr Laboratories, Inc; 2003.