How long is it safe to use Estring?

Aug 28, 2023

Estring is an FDA-approved estradiol vaginal ring used to reduce menopausal symptoms like painful sex and vaginal dryness. Once inserted, it slowly releases a low dose of estrogen and only has to be replaced every 90 days.

Estrogen therapy such as Estring is not intended as a long-term therapy. It should be used at the lowest dose possible and only for as long as needed. The longer you use estrogens, the higher your risk of serious side effects such as blood clots, heart attack, stroke, heart disease, dementia, cancer, gallbladder disease, and liver problems. Your doctor should regularly discuss with you whether you still need treatment with Estring. You should also have a breast exam and mammogram (breast X-ray) once a year unless otherwise directed by your doctor.

Estring FAQs

What is Estring used for?

Estring is a brand-name vaginal estrogen that is manufactured by Pfizer. The active ingredient in Estring is estradiol, which is a synthetic form of estrogen. It is FDA-approved to treat moderate to severe vulvar (outer part of the vagina) and vaginal atrophy in postmenopausal women. It can cause symptoms, including vaginal dryness, burning, painful urination, and pain during sex.

Research has shown that using just an estrogen like Estring as hormone replacement therapy can increase your risk of uterine cancer. Because of this, Estring is typically only recommended for women who have undergone a hysterectomy. If you still have your uterus, you will need to take a progestin medication along with Estring treatments to reduce this risk.

How does Estring work?

Menopause naturally begins in women between the ages of 45 to 55. Estrogen levels begin to decrease, which can lead to symptoms of menopause such as hot flashes, fewer or no periods, insomnia, mood changes, night sweats, vaginal changes, weaker bones, and urinary tract infections (UTIs). Estring is a soft, flexible ring that is inserted in the vagina and left for 90 days. It will slowly release a low dose of estrogen to restore your levels back to normal to relieve symptoms of menopause.

What are the common side effects of Estring?

Some of the most common side effects of Estring seen in clinical trials include:

Headache
Yeast infection
Vaginal discharge
Back pain
Vaginal discomfort, pain, or irritation
Vaginal bleeding
Upper respiratory tract infection
Bacterial vaginal infection
Abdominal pain
Nausea

Other side effects of Estring include:

Breast pain
Breast tenderness
Genital itching
Hot flashes
Urinary tract infection
Increased triglycerides/cholesterol
Reduced sex drive
Sore throat
Vomiting
Dizziness
Fluid retention
Bloating

What are the serious side effects of Estring?

Estring sometimes causes more serious side effects such as:

Severe allergic reactions, including shortness of breath and angioedema (swelling of your face, tongue, or throat)
Increased risk of blood clots
Increased risk of heart attack, or stroke (sudden numbness or weakness on one side of your body, sudden severe headache, slurred speech, vision problems, or loss of balance)
Increased risk of uterine, ovarian, and breast cancer (tell your doctor of any new breast lumps)
Hypertension (high blood pressure)
Dementia
Hyperglycemia (high blood sugar)
Gallbladder disease that could require surgery
Changes in your thyroid hormone levels
Liver problems, including jaundice (yellowing of your skin and eyes)
Increased risk of toxic shock syndrome (TSS) with symptoms such as fever, diarrhea, nausea, vomiting, dizziness, muscle pain, faintness, or a sunburn-like rash on your face and body
Fibroids in your uterus

These are not all of the possible side effects of Estring. You should always seek medical advice from your healthcare professional for any questions or concerns about your medical condition or treatment. Be sure to read all patient information that comes with your medication. You can also report adverse effects to the FDA at www.fda.gov/medwatch or 1-800-FDA-1088.

What drugs interact with Estring?

When Estring is taken with other prescription drugs, over-the-counter medications, vitamins, and supplements, it may change how they work or increase the risk of side effects. There have not been any formal drug interaction studies done with Estring. However, estrogen is metabolized by the CYP3A4 enzyme so inducers or inhibitors of this enzyme can affect how well Estring works.

CYP3A4 inducers such as St. John's Wort, rifampin, carbamazepine, and phenobarbital may decrease the levels of estrogen in your blood which can make Estring less effective.

CYP3A4 inhibitors such as clarithromycin, erythromycin, ritonavir, grapefruit juice, ketoconazole, and itraconazole may increase the levels of estrogen in your blood which can cause more side effects.

Who should not use Estring?

You should not start using Estring if you:

Have any unusual vaginal bleeding. This can be a sign of uterine cancer and your doctor should check any unusual vaginal bleeding and find out the cause.
Currently have or have a history of certain cancers. Estring can increase your risk of cancer of the uterus, breast, or ovary.
Have had a previous heart attack or stroke.
Currently have or have a history of blood clots or liver disease.
Have a bleeding disorder.
Have an allergy to Estring or any of its ingredients/materials including silicone and barium.
Are pregnant or think you might be pregnant. If you think you are pregnant, take a pregnancy test. If it is positive, do not use Estring and contact your doctor.

What warnings or precautions are there with Estring?

You should be sure your healthcare provider is aware of all your medical conditions as they may need to monitor you more closely while on Estring. This includes:

Endometrial cancer
Breast cancer
Ovarian cancer
A blood disorder called porphyria
Asthma
Seizures (epilepsy)
Diabetes
Migraines or severe headaches
Endometriosis
Lupus
Angioedema (swelling of your face and tongue)
Heart disease
Liver, thyroid, or kidney problems
High cholesterol
High blood calcium levels
Scheduled surgery or will be on bed rest
Are breastfeeding as the hormone can pass into your breast milk

How do you store Estring?

Estring can be kept anywhere convenient as long as it is stored at room temperature between 59°F and 77°F (15°C and 25°C).

Can Estring cause dementia?

A recent observational study found that women in their 50s who took progestin and estrogen hormone replacement therapy (HRT) for menopausal symptoms had an increased risk of dementia within 20 years. After controlling for several factors that might add to the dementia risk, it was found that women who used this type of HRT had a 24% higher rate of dementia when compared to women who had never taken HRT.

It should be noted that this is an observational study so it cannot be certain that HRT was the cause of this higher rate of dementia. Further studies would be needed to confirm a link between menopausal HRT and dementia.