conjugated estrogens vaginal cream, Premarin Vaginal Cream
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.
Medical and Pharmacy Editor:
GENERIC NAME: conjugated estrogens vaginal cream
BRAND NAME: Premarin Vaginal Cream
DRUG CLASS AND MECHANISM: Estrogens are one of the two major classes of female hormones. (Progestins comprise the second major class). Estrogens are used primarily to treat the symptoms of menopause and states in which there is a deficiency of estrogen, for example, among women who have had their estrogen-producing ovaries removed. Conjugated estrogens are a mixture of several different estrogens (estrogen salts) that are derived from natural sources and blended to approximate the composition of estrogens in the urine of pregnant horses. The main components are sodium estrone sulphate and sodium equilin sulfate. Estrogens have widespread effects on tissues in the body. Estrogens cause growth and development of the female sexual organs and maintain female sexual characteristics such as the growth of underarm and pubic hair, body contours, and skeleton. Estrogens also increase secretions from the cervix and growth of the inner lining of the uterus (endometrium). Conjugated estrogens were first approved by the FDA in 1938.
GENERIC AVAILABLE: No
PREPARATIONS: 0.625 mg/gram
STORAGE: The cream should be stored at room temperature, 15-30 C (59-86 F).
PRESCRIBED FOR: Premarin vaginal cream is used for the relief of vaginal symptoms in postmenopausal women who have developed uncomfortable vaginal dryness, inflammation, or painful intercourse due to atrophy of the vagina and/or vulvae.
DOSING: The recommended dose is 0.5 to 2 grams administered daily for 21 days then off for 7 days. Twice weekly administration may also be used. Vaginal products work best if used at bedtime. The hands should first be washed and the applicator filled with cream from the tube. Lying on the back with the knees bent, individuals should insert the applicator into the vagina and push the applicator's plunger to deliver the cream. The applicator and plunger then should be washed with warm, soapy water and rinsed with plain water. The hands should be washed before and after use. A small amount of the cream also can be applied to the outer skin folds or "lips" of the vagina (vulvae) to relieve dryness or irritation.
DRUG INTERACTIONS: Premarin drug interaction studies have not been conducted. Estrogens are broken down in the liver by certain enzymes. Drugs that increase or decrease the activity of these enzymes may interfere with the action of Premarin. Rifampin (Rifadin), barbiturates, carbamazepine (Tegretol), griseofulvin (Grifulvin), phenytoin (Dilantin), St. John's wort, and primidone may increase the elimination of estrogen by enhancing the liver's ability to eliminate estrogens. Use of any of these medications with estrogens may result in a reduction of the beneficial effects of estrogens. Conversely, drugs such as erythromycin, ketoconazole (Nizoral), itraconazole (Sporanox), and ritonavir (Norvir) may reduce the elimination of estrogens by the liver and lead to increased levels of estrogens in the blood and increased effects. Grapefruit juice also may increase levels of estrogen by increasing the absorption of estrogens from the intestine. Increased levels of estrogens in the blood may result in more estrogen-related side effects.
PREGNANCY: Estrogens should be avoided during pregnancy since they increase the risk of fetal abnormalities.
NURSING MOTHERS: Estrogens are secreted in milk and cause unpredictable effects in the infant. In general, they should not be used by women who are breastfeeding.
SIDE EFFECTS: Among the most common endocrine side effects are breakthrough vaginal bleeding or spotting, loss of periods or excessively prolonged periods, breast pain or enlargement, and changes in sexuality (increases or decreases in libido).
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