Estring (Estradiol)
Estring Vaginal Ring
Estradiol
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Femring
Estradiol Acetate
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Nuvaring Vaginal Ring
Ethinyl Estradiol, Etonogestrel
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Prescription Required.

Product of Canada.

Shipped from Canada.

Prescription Required.Product of Canada.Shipped from Canada.

Estring (estradiol)

What is Estring (estradiol)?

Estring is an estradiol vaginal ring that contains 2 mg of estradiol that is consistently released into the vagina for 90 days. Estring is used to treat local symptoms of Menopause, such as itching, burning, and dryness in or around the vagina.

How does Estring work?

Estring is an off-white, flexible ring that releases estradiol into the vagina at a consistent rate for 90 days.

Estrogens are responsible for many functions in the human body, mainly for the development of the female reproductive system and secondary sex characteristics. Estradiol is the principal intracellular estrogen and is much more potent than its metabolites (estrone and estriol). Estradiol is the primary estrogen secreted before menopause, while estrone and estrone sulfate are more highly produced after menopause.

Estrogens modulate the pituitary secretion of gonadotropins, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) through a negative feedback loop. Estrogens act to reduce the elevated levels of these hormones in postmenopausal women.

Dosage and How to Use

Estring is only available as a 2 mg ring.

One Estring should be pressed into an oval and inserted as deeply as possible into the upper one-third of the vaginal vault. If the patient feels discomfort, Estring is probably not far enough inside.

The ring should remain in place for 90 days. The patient should not feel Estring when it is in place, and it should not interfere with sexual intercourse. Straining at defecation may make Estring move down in the lower part of the vagina. If so, it may be pushed up again with a finger.

After 90 days, the ring should be removed and, if indicated, replaced by a new ring. The need to continue treatment should be evaluated every 3 to 6 months.

If the ring falls out at any time during the 90-day treatment period, the ring should be rinsed in lukewarm water and re-inserted by the patient, physician, or nurse.

Retaining the ring for longer than 90 days will not cause overdosage, but it will result in progressively greater under dosage.

Estring can be removed by hooking a finger through the ring and pulling it out.

Storage

Store at room temperature 15° to 30° C (59° to 86° F).

Overdosage

Estrogen overdosage may cause nausea, vomiting, breast tenderness, abdominal pain, drowsiness, and withdrawal bleeding (in women). Overdosage treatment consists of removing Estring and appropriate care to reduce symptoms.

Side Effects

The more common side effects of Estring include:

  • Headache
  • Breast pain
  • Irregular vaginal bleeding or spotting
  • Stomach/abdominal cramps, bloating
  • Nausea and vomiting
  • Hair loss
  • Fluid retention
  • Vaginal yeast infection

Rare but serious side effects of Estring include:

  • Breast cancer
  • Cancer of the uterus
  • Stroke
  • Heart attack
  • Blood clots
  • Dementia
  • Gallbladder disease
  • Ovarian cancer
  • High blood pressure
  • Liver problems
  • High blood sugar
  • Enlargement of benign tumors of the uterus (“fibroids”)

Warning signs of a serious side effect may be:

  • Breast lumps
  • Unusual vaginal bleeding
  • Dizziness and faintness
  • Changes in speech
  • Severe headaches
  • Chest pain
  • Shortness of breath
  • Pains in your legs
  • Changes in vision
  • Vomiting
  • Yellowing of the skin, eyes, or nail beds

Call your doctor immediately if you experience any of these warning signs or any other unusual symptoms that raise concern.

This is not a comprehensive list of all possible side effects. Please contact your doctor or pharmacist for more information.

Warnings & Precautions

Boxed Warnings

Cardiovascular disorders (stroke, coronary heart disease, and venous thromboembolism)

  • The Women’s Health Initiative (WHI) estrogen-alone substudy reported increased risks of stroke and deep vein thrombosis (DVT).
  • The WHI estrogen plus progestin substudy reported increased risks of DVT, pulmonary embolism (PE), stroke, and myocardial infarction (MI).
  • Do not use estrogen-alone or estrogen plus progestogen therapy for the prevention of cardiovascular disease.

Malignant Neoplasms (endometrial cancer, breast cancer)

  • There is an increased risk of endometrial cancer in a woman with a uterus who uses unopposed estrogens.
  • The WHI estrogen plus progestin substudy reported increased risks of invasive breast cancer.

Dementia

  • The WHI Memory Study (WHIMS) estrogen-alone ancillary study of WHI reported an increased risk of developing probable dementia in postmenopausal women 65 years and older.
  • The WHIMS estrogen plus progestin ancillary study of WHI reported an increased risk of developing probable dementia in postmenopausal women 65 years and older.
  • Do not use estrogen-alone or estrogen plus progestogen therapy for the prevention of dementia.

Other Warnings & Precautions

  • Gallbladder disease
  • Hypercalcemia
  • Visual Abnormalities
  • Addition of a progestin should be strongly considered in women that have not had a hysterectomy
  • Elevated blood pressure
  • Hypertriglyceridemia
  • Impaired liver function and history of cholestatic jaundice
  • Hypothyroidism
  • Hypocalcemia
  • Fluid retention
  • Exacerbation of endometriosis
  • Exacerbation of other conditions (e.g., diabetes mellitus, epilepsy, migraine)
  • Vaginal irritation
  • Vaginal infection

Drug Interactions and Other Interactions

Studies have shown that estrogens are metabolized partially by cytochrome P450 3A4 (CYP3A4). Inducers or inhibitors of CYP3A4 may affect estrogen drug metabolism.

CYP3A4 inducers (e.g., St. John’s Wort, phenobarbital, carbamazepine, and rifampin) may reduce plasma concentrations of estrogens.

CYP3A4 inhibitors (e.g., clarithromycin, erythromycin, ketoconazole, itraconazole, ritonavir, grapefruit juice) may increase plasma concentrations of estrogens.

Contraindications

Estring should not be used in women with any of the following:

  • Undiagnosed abnormal genital bleeding
  • Known, suspected, or history of breast cancer or other estrogen-dependent neoplasia
  • Active or history of deep vein thrombosis or pulmonary embolism
  • Active or recent (within the past year) arterial thromboembolic disease (for example, stroke and myocardial infarction)
  • Known liver dysfunction
  • Known hypersensitivity to any of the ingredients in Estring
  • Known or suspected pregnancy

Frequently Asked Questions

Estring is an estradiol vaginal ring that contains 2 mg of estradiol that is consistently released into the vagina for 90 days.

Estring is used to treat local symptoms of Menopause, such as itching, burning, and dryness in or around the vagina.

You should not use Estring if you:

  • Have unusual vaginal bleeding
  • Known, suspected, or history of breast cancer or other estrogen-dependent cancer
  • Have or have had blood clots
  • Have or have had a stroke or heart attack in the last year
  • Have or have had liver problems
  • Are allergic to any of the ingredients in Estring
  • Think you may be pregnant

You should tell your doctor all the following information:

  • If you are breastfeeding
  • About all of your past and present medical problems
  • About all the medicines you take
  • Including prescription, over-the-counter, vitamins, and natural supplements
  • If you are going to have surgery or will be on bed rest

You should tell your doctor all the following information:

  • If you are breastfeeding
  • About all of your past and present medical problems
  • About all the medicines you take
  • Including prescription, over-the-counter, vitamins, and natural supplements
  • If you are going to have surgery or will be on bed rest

  • After washing and drying your hands, remove Estring from its pouch using the tear-off notch on the side. Make sure your hands are dry before handling it because the ring is slippery when wet.
  • Hold Estring between your thumb and index finger and press the opposite sides of the ring.
  • Gently push the compressed ring into your vagina as far as you can.

The exact position is not critical as long as it is within the upper third of the vagina.

If you feel discomfort, this likely means Estring is not far enough inside. Use your finger to gently push Estring further into the vagina. You should not feel any discomfort when Estring is in the proper place.

There is no risk of Estring being pushed too far, as the cervix will block it from going any further.

Estring should stay in place for 90 days. After 90 days, there will no longer be enough estradiol in the ring to have its full effect.

Estring may slide down to the lower part of the vagina as a result of abdominal pressure that can accompany constipation. If this happens, gently guide Estring with your finger back into the correct position.

If Estring completely falls out of the vagina, wash Estring in lukewarm water (not hot) and reinsert it.

After 90 days, Estring should be removed and replaced with a new Estring (if you are continuing treatment).

  • Wash and dry your hands thoroughly.
  • Assume a comfortable position, either standing with one leg up, squatting, or lying down.
  • Loop your finger through the ring and gently pull it out.
  • Discard the used ring in a waste receptacle. Do not flush Estring.

If you have trouble removing Estring, contact your doctor or healthcare provider.

The most common side effects of Estring are:

  • Headache
  • Breast pain
  • Irregular vaginal bleeding or spotting
  • Stomach/abdominal cramps, bloating
  • Nausea and vomiting
  • Hair loss
  • Fluid retention
  • Vaginal yeast infection

This is not a comprehensive list of all possible side effects. Please contact your doctor or pharmacist for more information.

Estring can cause some rare but serious side effects, including:

  • Breast cancer
  • Cancer of the uterus
  • Stroke
  • Heart attack
  • Blood clots
  • Dementia
  • Gallbladder disease
  • Ovarian cancer
  • High blood pressure
  • Liver problems
  • High blood sugar

This is not a comprehensive list of all possible side effects. Please contact your doctor or pharmacist for more information.

Contact your doctor immediately if you have any one of the following signs of a serious side effect:

  • Breast lumps
  • Unusual vaginal bleeding
  • Dizziness and faintness
  • Changes in speech
  • Severe headaches
  • Chest pain
  • Shortness of breath
  • Pains in your legs
  • Changes in vision
  • Vomiting
  • Yellowing of the skin, eyes, or nail beds

You can reduce your chances of serious side effects by:

  • Carefully following instructions for use
  • Discussing with your healthcare provider regularly if you should continue treatment with Estring
  • Contacting your doctor immediately if you have vaginal bleeding, fever, nausea, diarrhea, muscle pain, dizziness, sunburn-like rash, or anything else that concerns you
  • Having a breast exam and mammogram every year
  • Asking your doctor about ways to lower your chances of getting heart disease

You should avoid grapefruit and grapefruit juice because it can lead to unwanted side effects when using Estring.

No formal drug interaction studies have been done with Estring. However, estradiol is partially metabolized by CYP3A4, and CYP3A4 inhibitors or inducers can affect the levels of estradiol in your body.

CYP3A4 inhibitors (e.g., clarithromycin, erythromycin, ketoconazole, itraconazole, ritonavir, grapefruit juice) may increase levels of estrogens and lead to side effects.

CYP3A4 inducers (e.g., St. John’s Wort, phenobarbital, carbamazepine, and rifampin) can reduce levels of estrogens and decrease how well Estring works.

Estring is an off-white ring that contains 2 mg of estradiol in the core. The ring is made of estradiol, silicone polymers, and barium sulfate.