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See Boxed Warnings, WARNINGS and PRECAUTIONS.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In a 13-week clinical trial that included 225 postmenopausal women treated with Femring (estradiol acetate) and 108 women treated with placebo vaginal rings, adverse events that occurred at a rate of ≥ 2 percent are summarized in Table 6.

Table 6. Incidence of AEs Occurring in ≥ 2% of Subjects Presented in Descending Frequency of Preferred Term

Postmarketing Experience

1. A few cases of toxic shock syndrome (TSS) have been reported in women using vaginal rings. TSS is a rare, but serious disease that may cause death. Warning signs of TSS include fever, nausea, vomiting, diarrhea, muscle pain, dizziness, faintness, or a sunburn-rash on face and body.
2. A few cases of ring adherence to the vaginal or bladder wall, making ring removal difficult, have been reported in women using vaginal rings. Patients should be carefully evaluated for vaginal or bladder wall ulceration or erosion. If an ulceration or erosion has occurred, consideration should be given to leaving the ring out and not replacing it until healing is complete to prevent the ring from adhering to the vaginal tissue.
3. A few cases of bowel obstruction associated with vaginal ring use have been reported. Persistent abdominal complaints consistent with obstruction should be carefully evaluated.
4. A few cases of inadvertent ring insertion into the urinary bladder, which may require surgical removal, have been reported for women using vaginal rings. Persistent unexplained urinary symptoms should be carefully evaluated.

The following additional adverse reactions have been identified during post-approval use of Femring (estradiol acetate) . Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Genitourinary system

Uterine cancer, vaginal hemorrhage, ovarian cyst, irregular menstruation, metrorrhagia, menorrhagia, dysmenorrhea, uterine enlargement.

Breasts

Breast cancer, fibrocystic breast disease, breast disorder, breast mass, breast enlargement, breast pain, nipple pain, breast discharge.

Cardiovascular

Chest pain, increased blood pressure, irregular heart rate, pulmonary embolism, cerebrovascular accident (stroke), hemiparesis, transient ischemic attack, thrombosis.

Gastrointestinal

Abdominal pain, pancreatitis, cholecystitis, cholelithiasis, vomiting.

Skin

Generalized erythema, erythema multiforme, erythema nodosum, rash, hirsutism, pruritis.

Eyes

Blindness, contact lens intolerance.

Central Nervous System

Dizziness, headache, depression, nervousness, mood disturbances, irritability.

Miscellaneous

Medical device complication, back pain, angioedema, weight increased/decreased, edema, libido increased/decreased, urticaria, hypersensitivity, anaphylaxis.

Drug/Laboratory Test Interactions

1. Accelerated prothrombin time, partial thromboplastin time, and platelet aggregation time; increased platelet count; increased factors II, VII antigen, VIII antigen, VIII coagulant activity, IX, X, XII, VII-X complex, II-VII-X complex, and beta-thromboglobulin; decreased levels of antifactor Xa and antithrombin III, decreased antithrombin III activity; increased levels of fibrinogen and fibrinogen activity; increased plasminogen antigen and activity.
2. Increased thyroid-binding globulin (TBG) levels leading to increased circulating total thyroid hormone levels as measured by protein-bound iodine (PBI), T₄ levels (by column or by radioimmunoassay) or T₃ levels by radioimmunoassay. T₃ resin uptake is decreased, reflecting the elevated TBG. Free T₄ and free T₃ concentrations are unaltered. Women on thyroid replacement therapy may require higher doses of thyroid hormone.
3. Other binding proteins may be elevated in serum, for example, corticosteroid binding globulin (CBG), sex hormone binding globulin (SHBG)) leading to increased total circulating corticosteroids and sex steroids, respectively. Free hormone concentrations, such as testosterone and estradiol, may be decreased. Other plasma proteins may be increased (angiotensinogen/renin substrate, alpha-1-antitrypsin, ceruloplasmin).
4. Increased plasma HDL and HDL₂ cholesterol subfraction concentrations, reduced LDL cholesterol concentration, increased triglycerides levels.
5. Impaired glucose tolerance.

Last reviewed on RxList: 6/15/2009
This monograph has been modified to include the generic and brand name in many instances.