estrogens conjugated synthetic, Cenestin

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Pharmacy Author:

Omudhome Ogbru, PharmD

Omudhome Ogbru, PharmD

Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

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Medical and Pharmacy Editor:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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GENERIC NAME: conjugated estrogens, synthetic

BRAND NAME: Cenestin

DRUG CLASS AND MECHANISM: Cenestin is a combination of nine estrogens. Estrogens are hormones produced by the ovaries that are necessary for the proper development of the female reproductive system and sexual characteristics. After menopause, there is a decrease in the amount of estrogen that is produced by the ovaries. This decrease in estrogen production is responsible for hot flashes, mood changes, sleep disturbance, decreased sexual function and other symptoms associated with menopause. Estrogen deficiency also has been linked to heart disease and bone loss (osteoporosis). Cenestin is similar to conjugated estrogens (Premarin), the other drug used for treating hot flashes. Unlike the estrogens in Premarin which are obtained from natural sources and blended to approximate the composition of estrogens found in urine of pregnant horses, the estrogens in Cenestin are synthetic (man- made) and are produced from plant material. Therefore, the estrogens in Cenestin are different from the estrogens found in Premarin. The FDA approved Cenestin in March 1999.

GENERIC AVAILABLE: No

PRESCRIPTION: Yes

PREPARATIONS: Tablets: 0.3, 0.45, 0.625, 0.9, and 1.25 mg

STORAGE: Tablets should be stored at room temperature, 15 C to 30 C (59 F to 86 F).

PRESCRIBED FOR: Cenestin is used for the relief of moderate to severe hot flashes and vulvar and vaginal atrophy due to estrogen deficiency resulting from menopause.

DOSING: The lowest effective dose should be used, starting with 0.45 mg and gradually increasing to 1.25 mg a day for treatment of hot flashes and 0.3 mg for treatment of vulvar and vaginal atrophy.

DRUG INTERACTIONS: Rifampin, carbamazepine (Tegretol), barbiturates, and St. John's Wort increase the ability of the liver to convert estrogens into inactive compounds. Therefore, use of these drugs with Cenestin may decrease the effectiveness of Cenestin. Conversely, breakdown of estrogens by the liver is reduced by erythromycin, clarithromycin (Biaxin), ketoconazole, itraconazole (Sporanox), ritonavir (Norvir), and grapefruit juice. This increases blood levels of estrogens and may result in increased side effects.

PREGNANCY: Estrogens such as Cenestin should not be used during pregnancy because they increase the risk of birth defects in the fetus.

NURSING MOTHERS: Estrogens such as Cenestin may decrease the quantity and quality of breast milk and produce unpredictable effects in the infant. Nursing mothers should avoid taking estrogens.

SIDE EFFECTS: Common side effects of conjugated estrogens include headache, abdominal pain, nervousness, nausea, back pain, joint pain and vaginal bleeding. Patients also may experience vaginal spotting, loss of periods or excessively prolonged periods, breast pain, breast enlargement, and an increase or decrease in sexual drive.

Report Problems to the Food and Drug Administration You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088. Need help identifying pills and medications? Use the pill identifier tool on RxList.