How does this medication work? What will it do for me?
Conjugated estrogens belong to the class of medications known as estrogen replacement therapy. Estrogen is a female hormone that is produced by the ovaries. Once menopause is reached, the ovaries produce less estrogen and symptoms of menopause can occur. Conjugated estrogen is an estrogen replacement hormone used to manage menopausal symptoms such as abnormal uterine bleeding (spotting), hot flashes, sweating, and chills. This medication may also help treat and prevent osteoporosis caused by estrogen deficiency when combined with diet, calcium, and exercise.
For women who are not having menopause symptoms, this medication should only be used if the woman is at serious risk of osteoporosis and cannot take other medications normally given to prevent osteoporosis. It may also be used to treat a condition where the tissues of the vagina become weak (vaginal atrophy or atrophic vaginitis), but if a woman is not having any other symptoms of menopause, an estrogen product applied to the skin (such as a cream) may be a more appropriate choice. It is also used to replace estrogen hormones in situations where the body can no longer produce estrogen, and to treat men with inoperable progressing prostate cancer when other treatments have not worked.
This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.
Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.
What form(s) does this medication come in?
C.E.S. is no longer being manufactured for sale in Canada. For brands that may still be available, search under conjugated estrogens. This article is being kept available for reference purposes only. If you are using this medication, speak with your doctor or pharmacist for information about your treatment options.
How should I use this medication?
The recommended adult dose of conjugated estrogens ranges from 0.3 mg to 1.25 mg daily, depending on the condition being treated. The usual adult starting dose is 0.3 mg daily, which may be increased gradually until your symptoms are reduced. It is recommended that this medication be taken at the lowest dose possible and for the shortest duration required to treat the condition. It is important to have regular checkups with your doctor to decide if this medication is still necessary. Tablets can either be taken every day or in a cycle, such as 25 days on the medication each month and 5 days off.
Women who have not had their uterus removed should also take a progestogen (a different type of female hormone that protects the uterus from potential harmful effects caused by estrogen) for 10 to 14 days each month, or every day depending on the hormone strength and whether a menstrual period is desired or not. Talk with your doctor or pharmacist about the advantages and disadvantages of the different dosing schedules of estrogen and progestogen.
Conjugated estrogens may be taken with or without food. Swallow the tablets whole and do not divide, crush, or chew them.
Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.
It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.
Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.
Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.
Who should NOT take this medication?
Do not take conjugated estrogens if you:
- are allergic to conjugated estrogens or any ingredients of the medication
- are or may be pregnant
- have a history of known or suspected estrogen-dependent tumours such as breast or uterine cancer
- have active liver disease or dysfunction
- have active thrombophlebitis, thrombosis, or thromboembolic disorders (blood clotting problems)
- have or have had stroke, heart attack, or coronary heart disease
- have endometrial hyperplasia (increase in the thickness of the lining of the uterus)
- have had partial or complete loss of vision due to blood vessel-related eye disease
- have undiagnosed abnormal vaginal bleeding
- have migraine with or without aura
- have certain hereditary blood clotting disorders (e.g., protein C, protein S, or antithrombin deficiency)
What side effects are possible with this medication?
Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.
The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.
Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.
- change in sexual desire
- cramps in the lower stomach
- darkening of the skin
- diarrhea (mild)
- dizziness (mild)
- headaches (mild)
- loss of appetite
- migraine headaches
- problems with wearing contact lenses
- vomiting (usually with high doses)
- weight changes
Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- breast changes (lumps, swelling, discharge)
- changes in vaginal bleeding (spotting, breakthrough bleeding, prolonged or heavier bleeding, or complete stoppage of bleeding)
- fast, pounding heartbeat
- first migraine headache
- signs of gallbladder problems (e.g., severe upper-right abdominal pain, back pain between the shoulder blades, nausea, vomiting)
- signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
- signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
- signs of retaining fluid (e.g., swelling of feet or lower legs, sudden weight gain)
- skin rash or itchiness
- symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
- symptoms of increased blood pressure (e.g., headaches, dizziness, vision problems, shortness of breath)
Stop taking the medication and seek immediate medical attention if any of the following occur:
- signs of a serious allergic reaction (i.e., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
- sudden partial or complete loss of vision
- symptoms of a blood clot in the leg (e.g., sharp pain in the foot or unexplained leg swelling, pain, redness, or tenderness)
- symptoms of a blood clot in the lung (e.g., sharp pain in the chest, coughing blood, or sudden shortness of breath)
- symptoms of a heart attack (e.g., sudden pain or discomfort in the chest, neck, jaw, shoulder, arms, or back; shortness of breath; nausea or vomiting; cool, clammy skin; anxiety or denial)
- symptoms of a stroke (e.g., sudden weakness or numbness in the face, arm, or leg – even if the weakness is temporary; sudden trouble speaking; sudden confusion; sudden vision changes; sudden severe and unusual headache; or sudden dizziness or loss of balance)
- worsening of asthma (e.g., wheezing, shortness of breath, coughing, difficulty breathing)
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.
Are there any other precautions or warnings for this medication?
Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Note the following important information about estrogen:
The Women's Health Initiative (WHI) study results indicated an increased risk of heart attack, stroke, breast cancer, blood clots in the lungs, and blood clots in the leg veins in postmenopausal women during 5 years of treatment with 0.625 mg conjugated equine estrogens and 2.5 mg medroxyprogesterone compared to women receiving sugar tablets.
- Estrogens with or without progestins should be used for the shortest time period possible at the lowest dose that relieves your menopausal symptoms.
- Estrogens with or without progestins should not be used to prevent heart disease, heart attacks, or strokes.
Blood clotting disorders: Estrogens should not be used by people with active thrombophlebitis (inflammation of a vein leading to a clot) or thromboembolic disorders (diseases of blood clotting and abnormal circulation). Some studies have suggested that there is an increased risk for healthy women to develop blood clots in the groin, legs, or lungs (conditions called deep vein thrombosis or pulmonary embolism) when taking hormone replacement therapy.
Women with severe varicose veins or severe obesity, and those needing to stay in bed for 3 weeks or more, are generally considered to be at increased risk of blood clots.
If you have a family history of thromboembolic disorders (see above), or have experienced a blood clot either during pregnancy or while taking estrogens, inform your doctor so that you can be monitored closely. Women with cerebrovascular disease (such as stroke) or coronary artery disease (such as angina) should use estrogens with caution, and only if clearly needed.
Blood pressure: There have been reports of increased blood pressure in a small number of people taking this medication. Regular checkups by your doctor are recommended. If you have high blood pressure, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Cancer: Some studies have shown that estrogen replacement therapy may increase the risk of breast, ovarian, and endometrial cancer. While taking a progestin at the right time and with the estrogen reduces the risk of endometrial cancer to the same level as that of a woman who does not take estrogen, it does not seem to reduce the risk of breast or ovarian cancer. Discuss with your doctor whether any special monitoring is needed before you start this medication.
Women using estrogens should have regular breast examinations and should be taught how to do a breast self-examination. Your doctor may also recommend regular mammograms depending on your age, risk factors, and previous mammogram results. Discuss the benefits and risks with your doctor so that you can make an informed choice about using this medication.
Cholesterol: Oral estrogens can increase triglyceride levels in the blood. If you have high blood cholesterol levels, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Dementia: Women over age 65 receiving estrogen, with or without a progestin may be at increased risk of developing dementia (loss of memory and intellectual function). If you are over 65 years of age, your doctor should closely monitor you for loss of memory and intellectual function.
Depression: Estrogens have been known to cause mood swings and symptoms of depression. If you have depression or a history of depression, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you experience symptoms of depression such as poor concentration, changes in weight, changes in sleep, decreased interest in activities, or notice them in a family member who is taking this medication contact your doctor as soon as possible.
Diabetes: Estrogens can cause changes in blood glucose control for people who have diabetes or have risk factors for developing diabetes. If you have diabetes or are at risk for developing diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
People who have diabetes (or a predisposition to diabetes) should monitor their blood glucose levels closely to detect changes in blood glucose.
Fibroids: This medication may worsen fibroids, causing sudden enlargement, pain, or tenderness. If you notice these effects, contact your doctor.
Fluid retention: Estrogen may cause fluid retention. This can be dangerous for women with heart or kidney problems, epilepsy, or asthma. If you have any of these conditions, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
If you notice the symptoms of any of these conditions getting worse, contact your doctor.
Gallbladder disease: An increased risk of gallbladder disease has been reported in postmenopausal women taking oral estrogens. If you have a history of gall bladder disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you experience symptoms of gallbladder disease such as abdominal pain, possibly with fever and chills, contact your doctor as soon as possible.
Heart disease and stroke: Studies indicate an increased risk of heart disease and stroke with estrogen (with or without progestins) for postmenopausal women. If you experience symptoms of a heart attack (chest pain, tightness or pressure, sweating, nausea, feeling of impending doom) or stroke (sudden dizziness, headache, loss of speech, changes in vision, weakness or numbness in the arms and legs) while taking this medication, get immediate medical attention.
Kidney disease: People with kidney disease should be monitored by their doctor while using estrogen.
Lab tests: Estrogen can affect certain laboratory tests and cause inaccurate readings.
Liver disease: If you have or have had liver problems, you may require special monitoring by your doctor while you use this medication. Make sure to tell your doctor if you have ever had liver problems.
If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.
Migraine: People who are at risk of experiencing migraine may have an increased risk of stroke when taking conjugated estrogens. If you have migraine with aura, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Other medical conditions: If you have hypocalcemia (low calcium in the blood), lupus, phlebitis, or porphyria, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Regular physical examinations: While on this medication, be sure to have regular examinations, particularly breast exams and mammograms, as recommended by your physician.
Seizures: Estrogens may cause an increase in seizures. If you have a history of epilepsy or medical conditions that increase the risk of seizures, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Thyroid disease: Estrogens can increase the amount of thyroid hormone your body needs to work properly. If you are hypothyroid (have reduced amount of thyroid hormone in your body) and need estrogens, you may require an increased amount of thyroid hormone for it to continue to work properly. Discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Pregnancy: Estrogen should not be used during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: When taken by breast-feeding mothers, estrogen passes into breast milk and causes a decrease in the amount and quality of milk produced. If you are a breast-feeding mother and are taking conjugated estrogens, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Children: The safety and effectiveness of using this medication have not been established for children.
What other drugs could interact with this medication?
There may be an interaction between conjugated estrogens and any of the following:
If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:
- stop taking one of the medications,
- change one of the medications to another,
- change how you are taking one or both of the medications, or
- leave everything as is.
An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.
Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.
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