Generic name: Conjugated estrogens
Brand names: Premphase, Prempro, Cenestin, Premarin
Premarin is an estrogen replacement drug. The tablets are used to reduce moderate to severe symptoms of menopause, including feelings of warmth in the face, neck, and chest, and the sudden intense episodes of heat and sweating known as "hot flashes." Cenestin tablets, containing a synthetic form of conjugated estrogens, may also be prescribed for these symptoms.
In addition to the symptoms of menopause, Premarin tablets are prescribed for teenagers who fail to mature at the usual rate, and to relieve the symptoms of certain types of cancer, including some forms of breast and prostate cancer.
In addition, either the tablets or Premarin vaginal cream can be used for other conditions caused by lack of estrogen, such as dry, itchy external genitals and vaginal irritation.
Along with diet, calcium supplements, and exercise, Premarin tablets are also prescribed to prevent postmenopausal osteoporosis, a condition in which the bones become brittle and easily broken. Before taking Premarin solely for this purpose, you should carefully consider using alternative, nonestrogen therapies.
The addition of progesterone to estrogen-replacement therapy has been shown to reduce the risk of uterine cancer. Prempro combines estrogen and progesterone in a single tablet taken once daily. Premphase is a 28-day supply of tablets. The first 14 contain only estrogen. The second 14 supply both estrogen and progesterone. Both Prempro and Premphase are prescribed to reduce the symptoms of menopause, including vaginal problems, and to prevent osteoporosis.
Special warnings about Prempro
For women who have not had a hysterectomy, the risk of endometrial and uterine cancer increases when estrogen-only drugs are used for a long time or taken in large doses. Estrogen therapy can also worsen endometriosis (uterine tissue growing outside the uterus). If you've ever had endometriosis, make sure the doctor is aware of it. If you've had a hysterectomy but still have residual endometriosis, your doctor may want you to use an estrogen/progesterone combination.
Certain studies have shown that women taking estrogen for prolonged periods of time (4 years or more) face an increased risk of breast cancer, and a study by the National Heart, Lung and Blood Institute (NHLBI) has confirmed an increased risk among women taking estrogen/progesterone combinations. Use combination products (and estrogen-only preparations, too) with special caution if you have a family history of breast cancer or have ever had an abnormal mammogram. Be sure to get an annual breast exam from your doctor, and do your own self-examination each month.
The NHLBI study also found an increased risk of dementia for women taking estrogen or estrogen/progesterone combinations.
Because Premarin can increase the risk of heart attack, stroke, blood clots, and certain estrogen-dependent cancers, contact your doctor right away if you notice any of the following:
- Abdominal pain, tenderness, or swelling
- Abnormal bleeding from the vagina
- Breast lumps
- Coughing up blood
- Pain in your chest or calves
- Severe headache, dizziness, or faintness
- Sudden shortness of breath
- Vision changes
Women who take Premarin after menopause are more likely to develop gallbladder disease.
Estrogens such as Premarin can cause hypercalcemia, a severe increase of calcium levels in the blood. Women with breast or bone cancer are especially at risk and should stop taking Premarin immediately if they develop hypercalcemia. In addition, women with the opposite problem--hypocalcemia, or a severe decrease of calcium in the blood--should use Premarin with caution.
Women who have not had a hysterectomy and take estrogen along with progesterone have a lower risk of precancerous endometrial changes. However, you should be aware that estrogen/progesterone combinations could increase "bad" LDL cholesterol and blood sugar levels as well as increase the risk of breast cancer.
There is a slight chance that estrogen therapy could cause an increase in blood pressure. Ask your doctor to check your blood pressure regularly.
If you have high levels of fat in your blood, specifically a high triglyceride level, conjugated estrogens such as Premarin are likely to cause side effects in the pancreas.
Use Premarin with caution if you have a history of liver problems, including jaundice. Call your doctor right away if you develop abdominal pain or yellowing of the skin.
Premarin can alter thyroid function. If you're taking thyroid medication, you may need your dosage adjusted.
Premarin can also cause fluid retention. Use the drug with caution if you have heart or kidney problems, or any other condition that's affected by excess fluid in the body.
Some studies have shown that using estrogen-only drugs, especially for 10 years or more, could increase the risk of ovarian cancer. It's unknown whether this also applies to estrogen/progesterone combinations.
Estrogens such as Premarin have been known to make certain conditions worse, including asthma, diabetes, epilepsy, migraine, porphyria (a genetic enzyme deficiency), lupus, and liver tumors.
If you are using Premarin vaginal cream, you should be aware that this product can weaken latex condoms, diaphragms, and cervical caps.
