Rx Only
Femring® (estradiol acetate vaginal ring) is an off-white, soft, flexible ring with a central core containing estradiol acetate.
Femring is made of cured silicone elastomer composed of dimethyl polysiloxane silanol, silica (diatomaceous earth), normal propyl orthosilicate, stannous octoate; barium sulfate and estradiol acetate. The rings have the following dimensions: outer diameter 56 mm, cross-sectional diameter 7.6 mm, core diameter 2 mm.
Femring is available in two strengths: Femring 0.05 mg/day has a central core that contains 12.4 mg of estradiol acetate, which releases at a rate equivalent to 0.05 mg of estradiol per day for 3 months. Femring 0.10 mg/day has a central core that contains 24.8 mg of estradiol acetate, which releases at a rate equivalent to 0.10 mg of estradiol per day for 3 months.
Estradiol acetate is chemically described as estra-1,3,5(10)-triene-3,17β-diol-3-acetate. The molecular formula of estradiol acetate is C20H26O3 and the structural formula is:

The molecular weight of estradiol acetate is 314.41.
Endogenous estrogens are largely responsible for the development and maintenance of the female reproductive system and secondary sexual characteristics. Although circulating estrogens exist in a dynamic equilibrium of metabolic interconversions, estradiol is the principal intracellular human estrogen and is substantially more potent than its metabolites, estrone and estriol, at the receptor level.
The primary source of estrogen in normally cycling adult women is the ovarian follicle which secretes 70 to 500 mcg of estradiol daily depending on the phase of the menstrual cycle. After menopause, most endogenous estrogen is produced by conversion of androstenedione, secreted by the adrenal cortex, to estrone by peripheral tissues. Thus, estrone and the sulfate conjugated form, estrone sulfate, are the most abundant circulating estrogens in postmenopausal women.
Estrogens act through binding to nuclear receptors in estrogen-responsive tissues. To date, two estrogen receptors have been identified. These vary in proportion from tissue to tissue.
Circulating estrogens modulate the pituitary secretion of the gonadotropins, luteinizing hormone (LH) and follicle stimulating hormone (FSH) through a negative feedback mechanism. Estrogens act to reduce the elevated levels of these hormones seen in postmenopausal women.
Estradiol acetate is rapidly hydrolyzed to estradiol.
Drug delivery from Femring is rapid for the first hour and then declines to a relatively constant rate for the remainder of the 3-month dosing interval. In vitro studies have shown that this initial release is higher as the rings age upon storage. Estradiol acetate and estradiol are rapidly absorbed through the vaginal mucosa as evidenced by tmax values for estradiol of less than 1 hour. Following Cmax, serum estradiol concentrations decrease rapidly such that by 24 to 48 hours postdose, serum estradiol concentrations are relatively constant through the end of the 3-month dosing interval, see Figure 1. Mean serum estradiol concentrations following multiple dose administration of Femring (0.05 mg/day estradiol) (second dose administered at 13 weeks) (inset: mean (±SD) of serum concentration-time profile for dose 1 from 0-24 hours) for results from rings stored for 16 months.
Following administration of Femring (0.05 mg/day estradiol), average serum estradiol concentration was 40.6 pg/mL; the corresponding apparent in vivo estradiol delivery rate was 0.052 mg/day. Following administration of Femring (0.10 mg/day estradiol), average serum estradiol concentration was 76 pg/mL; apparent in vivo delivery rate was 0.097 mg/day. Results are summarized in Table 1. Summary of Mean (%RSD)* Pharmacokinetic Parameters for Femring below.
Dose (as estradiol) | Number of subjects | Cmax (pg/mL) | Tmax (hour) | Cavg (pg/mL) | |
0.05 mg/day | Estradiol1 | 25 | 1129 (25) | 0.9 (41) | 40.6 (26) |
| Estrone1 | 25 | 141 (25) | 6.2 (84) | 35.9 (21) | |
| Estrone sulfate1 | 25 | 2365 (44) | 9.3 (39) | 494.6 (48) | |
0.10 mg/day | Estradiol2 | 12 | 1665 (23) | 0.7 (90) | --4 |
| Estradiol3 | 11 | -- | -- | 76.0 (24) | |
| Estrone3 | 11 | -- | -- | 45.7 (25) | |
| * Relative Standard Deviation, 1Study 1, 2Study 2, 3Study 3, 4-- Not determined | |||||
Consistent with the avoidance of first pass metabolism achieved by vaginal estradiol administration, serum estradiol concentrations were slightly higher than estrone concentrations.
The distribution of exogenous estrogens is similar to that of endogenous estrogens. Estrogens are widely distributed in the body and are generally found in higher concentrations in the sex hormone target organs. Estrogens circulate in the blood largely bound to sex hormone binding globulin (SHBG) and to albumin.
Exogenous estrogens are metabolized in the same manner as endogenous estrogens. Circulating estrogens exist in a dynamic equilibrium of metabolic interconversions. These transformations take place mainly in the liver. Estradiol is converted reversibly to estrone, and both can be converted to estriol, which is the major urinary metabolite. Estrogens also undergo enterohepatic recirculation via sulfate and glucuronide conjugation in the liver, biliary secretion of conjugates into the intestine, and hydrolysis in the gut followed by reabsorption. In postmenopausal women, a significant proportion of the circulating estrogens exist as sulfate conjugates, especially estrone sulfate, which serves as a circulating reservoir for the formation of more active estrogens.
Estradiol, estrone, and estriol are excreted in the urine along with glucuronide and sulfate conjugates.
No pharmacokinetic studies were conducted in special populations, including patients with renal or hepatic impairment.
In vitro and in vivo studies have shown that estrogens are metabolized partially by cytochrome P450 3A4 (CYP3A4). Therefore, inducers or inhibitors of CYP3A4 may affect estrogen drug metabolism. Inducers of CYP3A4 such as St. John’s Wort preparations (Hypericum perforatum), phenobarbital, carbamazepine and rifampin may reduce plasma concentrations of estrogens, possibly resulting in a decrease in therapeutic effects and/or changes in the uterine bleeding profile. Inhibitors of CYP3A4 such as erythromycin, clarithromycin, ketoconazole, itraconazole, ritonavir and grapefruit juice may increase plasma concentrations of estrogens and may result in side effects.
A 13-week double-blind, placebo-controlled clinical trial was conducted to evaluate the efficacy of 2 doses of the vaginal ring in the treatment of moderate to severe vasomotor symptoms in 333 postmenopausal women between 29 and 85 years of age (mean age 51.7 years, 77% were Caucasian) who had at least 7 moderate to severe hot flushes daily or at least 56 moderate to severe hot flushes per week before randomization. Patients were randomized to receive either placebo, Femring 0.05 mg/day or Femring 0.10 mg/day. Femring 0.05 mg/day and Femring 0.10 mg/day were shown to be statistically better than placebo at weeks 4 and 12 for relief of both the frequency and severity of moderate to severe vasomotor symptoms. Frequency results are shown in Table 2. Mean Change from Baseline in the Number of Moderate to Severe Vasomotor Symptoms per Week – ITT Population, LOCF . Severity results are shown in Table 3. Mean Change from Baseline in the Severity of Moderate to Severe Vasomotor Symptoms per Week – ITT Population, LOCF .
| Visit | Placebo (n = 105) | Estradiol 0.05 mg/day (n = 111) | Estradiol 0.10 mg/day (n = 109) |
| Baseline [1] | |||
| Mean (SD) | 83.62 (60.42) | 73.83 (24.53) | 75.11 (25.44) |
| Week 4 | |||
| Mean (SD) | 51.14 (51.19) | 21.59* (27.76) | 11.37* (19.43) |
| Mean Change from Baseline (SD) | -32.48 (46.25) | -52.24* (32.92) | -63.75* (26.68) |
| p value vs. Placebo (95% CI) [2] | - | <0.001 (-30.7, -8.8) | <0.001 (-42.2, -20.3) |
| Week 12 | |||
| Mean (SD) | 42.21 (41.13) | 15.48* (25.42) | 8.25* (16.58) |
| Mean Change from Baseline (SD) | -41.41 (65.61) | -58.36* (31.36) | -66.87* (27.44) |
| p value vs. Placebo (95% CI) [2] | - | 0.006 (-30.5, -3.4) | <0.001 (-39.1, -11.8) |
*Denotes statistical significance at the 0.050 level [1] The baseline number of moderate to severe vasomotor symptoms (MSVS) is the weekly average number of MSVS during the two weeks between screening and randomization. [2] p values and confidence intervals are from a two-way ANOVA with factors for treatment and study center for the difference between treatment groups in the mean change from baseline. Confidence intervals are adjusted for multiple comparisons within each timepoint using Dunnett’s method. ITT = intent to treat; LOCF = last observation carried forward; CI = confidence interval | |||
Visit | Placebo (n = 105) | Estradiol 0.05 mg/day (n = 111) | Estradiol 0.10 mg/day (n = 109) |
| Baseline [1] | |||
| Mean (SD) | 2.51 (0.26) | 2.46 (0.23) | 2.48 (0.24) |
| Week 4 | |||
| Mean (SD) | 2.23 (0.71) | 1.67* (1.07) | 1.15* (1.14) |
| Mean Change from Baseline (SD) | -0.28 (0.69) | - 0.79* (1.08) | -1.33* (1.10) |
| p value vs. Placebo (95% CI) [2] | - | <0.001 (-0.8, -0.2) | <0.001 (-1.3, -0.8) |
| Week 12 | |||
| Mean (SD) | 2.00 (0.96) | 1.41* (1.17) | 0.92* (1.09) |
| Mean Change from Baseline (SD) | -0.51 (0.94) | -1.06* (1.16) | -1.56* (1.06) |
| p value vs. Placebo (95% CI) [2] | - | <0.001 (-0.9, -0.2) | <0.001 (-1.4, -0.7) |
*Denotes statistical significance at the 0.050 level [1] The baseline severity of moderate to severe vasomotor symptoms (MSVS) is the average severity of MSVS during the two weeks between screening and randomization. [2] p values and confidence intervals are from a two-way ANOVA with factors for treatment and study center for the difference between treatment groups in the mean change from baseline. Confidence intervals are adjusted for multiple comparisons within each timepoint using Dunnett’s method. ITT = intent to treat; LOCF = last observation carried forward; CI = confidence interval | |||
In the same 13-week clinical trial, vaginal superficial cells increased by a mean of 16.0% and 18.9% for Femring 0.05 mg/day and Femring 0.10 mg/day, respectively, as compared to 1.11% for placebo at week 13. A corresponding reduction in parabasal cells was observed at week 13. Vaginal pH decreased for Femring 0.05 mg/day and Femring 0.10 mg/day by a mean of 0.73 and 0.60, respectively, compared to a mean decrease of 0.25 in the placebo group.
The Women’s Health Initiative (WHI) study enrolled a total of 27,000 predominantly healthy postmenopausal women in two substudies to assess the risks and benefits of either the use of oral 0.625 mg conjugated estrogens (CE) per day alone or the use of oral 0.625 mg conjugated estrogens plus 2.5 mg medroxyprogesterone acetate (MPA) per day compared to placebo in the prevention of certain chronic diseases. The primary endpoint was the incidence of coronary heart disease (CHD) (nonfatal myocardial infarction (MI), silent MI and CHD death), with invasive breast cancer as the primary adverse outcome studied. A “global index” included the earliest occurrence of CHD, invasive breast cancer, stroke, pulmonary embolism (PE), endometrial cancer (only in CE/MPA), colorectal cancer, hip fracture or death due to other cause. The study did not evaluate the effects of CE or CE/MPA on menopausal symptoms.
The estrogen-alone substudy was stopped early because an increased risk of stroke was observed, and it was deemed that no further information would be obtained regarding the risks and benefits of estrogen alone in predetermined primary endpoints. Results of the estrogen-alone substudy, which included 10,739 women (average age of 63 years, range 50 to 79; 75.3% White, 15.1% Black, 6.1% Hispanic, 3.6% Other) after an average follow-up of 6.8 years, are presented in TABLE 4. RELATIVE AND ABSOLUTE RISK SEEN IN THE ESTROGEN-ALONE SUBSTUDY OF WHI below.
Event | Relative Risk CE vs. Placebo (95% nCIa) | CE n = 5,310 | Placebo n = 5,429 |
| Absolute Risk per 10,000 Women-Years | |||
| CHD eventsb | 0.95 (0.79-1.16) | 53 | 56 |
| Non-fatal MIb | 0.91 (0.73-1.14) | 40 | 43 |
| CHD deathb | 1.01 (0.71-1.43) | 16 | 16 |
| Strokec | 1.39 (1.10-1.77) | 44 | 32 |
| Deep vein thrombosisb,d | 1.47 (1.06-2.06) | 23 | 15 |
| Pulmonary embolismb | 1.37 (0.90-2.07) | 14 | 10 |
| Invasive breast cancerb | 0.80 (0.62-1.04) | 28 | 34 |
| Colorectal cancerc | 1.08 (0.75-1.55) | 17 | 16 |
| Hip fracturec | 0.61 (0.41-0.91) | 11 | 17 |
| Vertebral fracturesc,d | 0.62 (0.42-0.93) | 11 | 17 |
| Total fracturesc,d | 0.70 (0.63-0.79) | 139 | 195 |
| Death due to other causesc,e | 1.08 (0.88-1.32) | 53 | 50 |
| Overall mortalityc,d | 1.04 (0.88–1.22) | 81 | 78 |
| Global Indexc,f | 1.01 (0.91-1.12) | 192 | 190 |
| aNominal confidence intervals unadjusted for multiple looks and multiple comparisons. | |||
| bResults are based on centrally adjudicated data for an average follow-up of 7.1 years. | |||
| cResults are based on an average follow-up of 6.8 years. | |||
| dNot included in Global Index. | |||
| eAll deaths, except from breast or colorectal cancer, definite/probable CHD, PE or cerebrovascular disease. | |||
| fA subset of the events was combined in a “global index,” defined as the earliest occurrence of CHD events, invasive breast cancer, stroke, pulmonary embolism, colorectal cancer, hip fracture, or death due to other causes. | |||
For those outcomes included in the WHI “global index” that reached statistical significance, the absolute excess risk per 10,000 women-years in the group treated with CE alone were 12 more strokes while the absolute risk reduction per 10,000 women-years was six fewer hip fractures. The absolute excess risk of events included in the “global index” was a nonsignificant two events per 10,000 women-years. There was no difference between the groups in terms of all-cause mortality. (See BOXED WARNINGS, WARNINGS, and PRECAUTIONS.)
Final adjudicated results for CHD events from the estrogen-alone substudy, after an average follow-up of 7.1 years, reported no overall difference for primary CHD events (nonfatal MI, silent MI and CHD death) in women receiving CE alone compared with placebo (see TABLE 4. RELATIVE AND ABSOLUTE RISK SEEN IN THE ESTROGEN-ALONE SUBSTUDY OF WHI ).
The CE/MPA substudy was also stopped early. According to the predefined stopping rule, after an average follow-up of 5.2 years of treatment, the increased risk of breast cancer and cardiovascular events exceeded the specified benefits included in the “global index”. The absolute excess risk of events included in the “global index” was 19 per 10,000 women-years (RR 1.15, 95% nCI 1.03-1.28).
For those outcomes included in the WHI “global index” that reached statistical significance after 5.6 years of follow-up, the absolute excess risks per 10,000 women-years in the group treated with CE/MPA were six more CHD events, seven more strokes, ten more PEs, and eight more invasive breast cancers, while the absolute risk reductions per 10,000 women-years were seven fewer colorectal cancers and five fewer hip fractures. (See BOXED WARNINGS, WARNINGS, and PRECAUTIONS.)
Results of the CE/MPA substudy, which included 16,608 women (average age of 63 years, range 50 to 79; 83.9% White, 6.5% Black, 5.5% Hispanic, 3.9% Other), after an average follow-up of 5.6 years are presented in TABLE 5. RELATIVE AND ABSOLUTE RISK SEEN IN THE ESTROGEN-PLUS-PROGESTIN SUBSTUDY OF WHI AT AN AVERAGE OF 5.6 YEARSa below.
Event | Relative Risk CE/MPA vs. Placebo (95% nCIb) | CE/MPA n = 8,506 | Placebo n = 8,102 |
| Absolute Risk per 10,000 Women-Years | |||
| CHD events | 1.24 (1.00-1.54) | 39 | 33 |
| Non-fatal MI | 1.28 (1.00-1.63) | 31 | 25 |
| CHD death | 1.10 (0.70-1.75) | 8 | 8 |
| All strokes | 1.31 (1.02-1.68) | 31 | 24 |
| Ischemic Stroke | 1.44 (1.09-1.90) | 26 | 18 |
| Deep vein thrombosis | 1.95 (1.43-2.67) | 26 | 13 |
| Pulmonary embolism | 2.13 (1.45-3.11) | 18 | 8 |
| Invasive breast cancerc | 1.24 (1.01-1.54) | 41 | 33 |
| Invasive colorectal cancer | 0.56 (0.38-0.81) | 9 | 16 |
| Endometrial cancer | 0.81 (0.48-1.36) | 6 | 7 |
| Cervical cancer | 1.44 (0.47-4.42) | 2 | 1 |
| Hip fracture | 0.67 (0.47-0.96) | 11 | 16 |
| Vertebral fractures | 0.65 (0.46-0.92) | 11 | 17 |
| Lower arm/wrist fractures | 0.71 (0.59-0.85) | 44 | 62 |
| Total fractures | 0.76 (0.69-0.83) | 152 | 199 |
| aResults are based on centrally adjudicated data. Mortality data was not part of the adjudicated data; however, data at 5.2 years of follow-up showed no difference between the groups in terms of all-cause mortality (RR 0.98, 95% nCI 0.82-1.18). | |||
| bNominal confidence intervals unadjusted for multiple looks and multiple comparisons. | |||
| cIncludes metastatic and non-metastatic breast cancer, with the exception of in situ breast cancer. | |||
The estrogen-alone Women's Health Initiative Memory Study (WHIMS), a substudy of WHI, enrolled 2,947 predominantly healthy postmenopausal women 65 years of age and older (45%, age 65 to 69 years; 36%, 70 to 74 years; 19%, 75 years of age and older) to evaluate the effects of CE 0.625 mg daily on the incidence of probable dementia (primary outcome) compared with placebo.
After an average follow-up of 5.2 years, 28 women in the estrogen-alone group (37 per 10,000 women-years) and 19 in the placebo group (25 per 10,000 women-years) were diagnosed with probable dementia. The relative risk of probable dementia in the estrogen-alone group was 1.49 (95% CI 0.83–2.66) compared to placebo. It is unknown whether these findings apply to younger postmenopausal women. (See BOXED WARNINGS, WARNINGS, 3. Dementia and PRECAUTIONS, I. Geriatric use.)
The estrogen-plus-progestin WHIMS substudy enrolled 4,532 predominantly healthy postmenopausal women 65 years of age and older (47% were age 65 to 69 years, 35% were 70 to 74 years, and 18% were 75 years of age and older) to evaluate the effects of CE/MPA (0.625 mg conjugated estrogens plus 2.5 mg medroxyprogesterone acetate) on the incidence of probable dementia (primary outcome) compared with placebo.
After an average follow-up of 4 years, 40 women in the estrogen/progestin group (45 per 10,000 women-years) and 21 in the placebo group (22 per 10,000 women-years) were diagnosed with probable dementia. The relative risk of probable dementia in the hormone therapy group was 2.05 (95% CI, 1.21 to 3.48) compared to placebo.
When data from the two populations were pooled as planned in the WHIMS protocol, the reported overall relative risk for probable dementia was 1.76 (95% CI 1.19-2.60). Differences between groups became apparent in the first year of treatment. It is unknown whether these findings apply to younger postmenopausal women. (See BOXED WARNINGS, WARNINGS, 3. Dementia and PRECAUTIONS, I. Geriatric use..)
Femring therapy is indicated in the:
Femring should not be used in women with any of the following conditions:
See BOXED WARNINGS
Estrogen-alone therapy has been associated with an increased risk of stroke and deep vein thrombosis (DVT).
Estrogen-plus-progestin therapy has been associated with an increased risk of myocardial infarction as well as stroke, venous thrombosis and pulmonary embolism.
Should any of these occur or be suspected, estrogens should be discontinued immediately.
Risk factors for arterial vascular disease (e.g., hypertension, diabetes mellitus, tobacco use, hypercholesterolemia and obesity) and/or venous thromboembolism (e.g., personal history or family history of VTE, obesity and systemic lupus erythematosus) should be managed appropriately.
In the estrogen-alone Women's Health Initiative Memory Study (WHIMS), a substudy of WHI, a population of 2,947 hysterectomized women aged 65 to 79 years was randomized to CE (0.625 mg daily) or placebo. In the estrogen-plus-progestin WHIMS substudy, a population of 4,532 postmenopausal women aged 65 to 79 years was randomized to CE/MPA (0.625 mg/2.5 mg daily) or placebo.
In the estrogen-alone substudy, after an average follow-up of 5.2 years, 28 women in the estrogen-alone group and 19 women in the placebo group were diagnosed with probable dementia. The relative risk of probable dementia for CE alone vs. placebo was 1.49 (95% CI 0.83-2.66). The absolute risk of probable dementia for CE alone vs. placebo was 37 vs. 25 cases per 10,000 women-years.
In the estrogen-plus-progestin substudy, after an average follow-up of four years, 40 women in the estrogen-plus-progestin group and 21 women in the placebo group were diagnosed with probable dementia. The relative risk of probable dementia for estrogen plus progestin vs. placebo was 2.05 (95% CI 1.21-3.48). The absolute risk of probable dementia for CE/MPA vs. placebo was 45 vs. 22 cases per 10,000 women-years.
When data from the two populations were pooled as planned in the WHIMS protocol, the reported overall relative risk for probable dementia was 1.76 (95% CI 1.19-2.60). Since both substudies were conducted in women aged 65 to 79 years, it is unknown whether these findings apply to younger postmenopausal women. (See BOXED WARNINGS and PRECAUTIONS, I. Geriatric use.)
A 2- to 4-fold increase in the risk of gallbladder disease requiring surgery in postmenopausal women receiving estrogens has been reported.
Estrogen administration may lead to severe hypercalcemia in patients with breast cancer and bone metastases. If hypercalcemia occurs, use of the drug should be stopped and appropriate measures taken to reduce the serum calcium level.
Retinal vascular thrombosis has been reported in patients receiving estrogens. Discontinue medication pending examination if there is sudden partial or complete loss of vision, or a sudden onset of proptosis, diplopia or migraine. If examination reveals papilledema or retinal vascular lesions, estrogens should be permanently discontinued.
1. Addition of a progestin when a woman has not had a hysterectomy
Studies of the addition of a progestin for 10 or more days of a cycle of estrogen administration, or daily with estrogen in a continuous regimen, have reported a lowered incidence of endometrial hyperplasia than would be induced by estrogen treatment alone. Endometrial hyperplasia may be a precursor to endometrial cancer.
There are, however, possible risks that may be associated with the use of progestins with estrogens compared to estrogen-alone regimens. These include a possible increased risk of breast cancer, adverse effects on lipoprotein metabolism (e.g., lowering HDL, raising LDL) and impairment of glucose tolerance.
2. Elevated blood pressure
In a small number of case reports, substantial increases in blood pressure have been attributed to idiosyncratic reactions to estrogens. In a large, randomized, placebo-controlled clinical trial, a generalized effect of estrogens on blood pressure was not seen. Blood pressure should be monitored at regular intervals with estrogen use.
3. Hypertriglyceridemia
In patients with preexisting hypertriglyceridemia, estrogen therapy may be associated with elevations of plasma triglycerides leading to pancreatitis and other complications.
4. Impaired liver function and a past history of cholestatic jaundice
Estrogens may be poorly metabolized in patients with impaired liver function. For patients with a history of cholestatic jaundice associated with past estrogen use or with pregnancy, caution should be exercised and in the case of recurrence, medication should be discontinued.
5. Hypothyroidism
Estrogen administration leads to increased thyroid-binding globulin (TBG) levels. Patients with normal thyroid function can compensate for the increased TBG by making more thyroid hormone, thus maintaining free T4 and T3 serum concentrations in the normal range. Patients dependent on thyroid hormone replacement therapy who are also receiving estrogens may require increased doses of their thyroid replacement therapy. These patients should have their thyroid function monitored in order to maintain their free thyroid hormone levels in an acceptable range.
6. Fluid retention
Because estrogens may cause some degree of fluid retention, patients with conditions that might be influenced by this factor, such as cardiac or renal dysfunction, warrant careful observation when estrogens are prescribed.
7. Hypocalcemia
Estrogens should be used with caution in individuals with severe hypocalcemia.
8. Ovarian cancer
The CE/MPA substudy of WHI reported that after an average follow-up of 5.6 years, the relative risk for ovarian cancer for CE/MPA versus placebo was 1.58 (95% nCI 0.77-3.24) but was not statistically significant. The absolute risk for CE/MPA versus placebo was 4.2 versus 2.7 cases per 10,000 women-years. In some epidemiologic studies, the use of estrogen alone, in particular for ten or more years, has been associated with an increased risk of ovarian cancer. Other epidemiologic studies have not found these associations.
9. Exacerbation of endometriosis
Endometriosis may be exacerbated with administration of estrogens. A few cases of malignant transformation of residual endometrial implants have been reported in women treated post-hysterectomy with estrogen alone therapy. For patients known to have residual endometriosis post-hysterectomy, the addition of progestin should be considered.
10. Exacerbation of other conditions
Estrogens may cause an exacerbation of asthma, diabetes mellitus, epilepsy, migraine or porphyria, systemic lupus erythematosus and hepatic hemangiomas, and should be used with caution in women with these conditions.
Malignant transformation of residual endometrial implants have been reported in women treated post-hysterectomy with estrogen-alone therapy. For patients known to have residual endometriosis post-hysterectomy, the addition of progestin should be considered.
11. Vaginal use and expulsion
Femring may not be suitable for women with conditions that make the vagina more susceptible to vaginal irritation or ulceration, or make expulsions more likely, such as narrow vagina, vaginal stenosis, vaginal infection, cervical prolapse, rectoceles and cystoceles. If local treatment of a vaginal infection is required, Femring can remain in place during treatment.
12. Toxic Shock Syndrome (TSS)
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.
Physicians are advised to discuss the PATIENT INFORMATION leaflet with patients for whom they prescribe Femring.
Estrogen administration should be initiated at the lowest dose approved for the indication and then guided by clinical response rather than by serum hormone levels (e.g., estradiol, FSH).
Long-term continuous administration of estrogen, with and without progestin, in women with and without a uterus, has shown an increased risk of endometrial cancer, breast cancer and ovarian cancer. (See BOXED WARNINGS, WARNINGSand PRECAUTIONS.)
Long-term continuous administration of natural and synthetic estrogens in certain animal species increases the frequency of carcinomas of the breast, uterus, cervix, vagina, testis, and liver.
Estradiol acetate was assayed for mutation in four histidine-requiring strains of Salmonella typhimurium and in two tryptophan-requiring strains of Escherichia coli. Estradiol acetate did not induce mutation in any of the bacterial strains tested under the conditions employed.
Femring should not be used during pregnancy. (See CONTRAINDICATIONS.)
Estrogen administration to nursing mothers has been shown to decrease the quantity and quality of the milk. Detectable amounts of estrogens have been identified in the milk of mothers receiving this drug. Caution should be exercised when Femring is administered to a nursing woman.
Safety and effectiveness in pediatric patients have not been established.
Clinical studies of Femring did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greatest frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.
Of the total number of subjects in the estrogen-alone substudy of the Women's Health Initiative (WHI) study, 46% (n = 4,943) were 65 years and over, while 7.1% (n = 767) were 75 years and over. There was a higher relative risk (CE vs. placebo) of stroke in women less than 75 years of age compared to women 75 years and over.
In the estrogen-alone Women's Health Initiative Memory Study (WHIMS), a substudy of WHI, a population of 2,947 hysterectomized women, aged 65 to 79 years, was randomized to CE (0.625 mg daily) or placebo. After an average follow-up of 5.2 years, the relative risk (CE vs. placebo) of probable dementia was 1.49 (95% CI 0.83-2.66). The absolute risk of developing probable dementia with estrogen alone was 37 vs. 25 cases per 10,000 women-years with placebo.
Of the total number of subjects in the estrogen-plus-progestin substudy of the Women's Health Initiative study, 44% (n = 7,320) were 65–74 years of age, while 6.6% (n = 1,095) were 75 years and over. There was a higher relative risk (CE/MPA vs. placebo) of non-fatal stroke and invasive breast cancer in women 75 and over compared to women less than 75 years of age. In women greater than 75, the increased risk of non-fatal stroke and invasive breast cancer observed in the estrogen-plus-progestin combination group compared to the placebo group was 75 vs. 24 per 10,000 women-years and 52 vs. 12 per 10,000 women-years, respectively.
In the estrogen-plus-progestin WHIMS substudy, a population of 4,532 postmenopausal women, aged 65 to 79 years, was randomized to CE/MPA (0.625 mg/2.5 mg daily) or placebo. In the estrogen-plus-progestin group, after an average follow-up of four years, the relative risk (CE/MPA vs. placebo) of probable dementia was 2.05 (95% CI 1.21-3.48).The absolute risk of developing probable dementia with CE/MPA was 45 vs. 22 cases per 10,000 women-years with placebo.
Seventy-nine percent of the cases of probable dementia occurred in women that were older than 70 for the CE group, and 82 percent of the cases of probable dementia occurred in women who were older than 70 in the CE/MPA group. The most common classification of probable dementia in both the treatment groups and placebo groups was Alzheimer’s disease.
When data from the two populations were pooled as planned in the WHIMS protocol, the reported overall relative risk for probable dementia was 1.76 (95% CI 1.19-2.60). Since both substudies were conducted in women aged 65 to 79 years, it is unknown whether these findings apply to younger postmenopausal women. (See BOXED WARNINGS and WARNINGS, 3. Dementia.)
See BOXED WARNINGS, WARNINGSand 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. The adverse reaction information from clinical trials does, however, provide a basis for identifying the adverse events that appear to be related to drug use and for approximating rates.
In a 13-week clinical trial that included 225 postmenopausal women treated with Femring and 108 women treated with placebo vaginal rings, adverse events that occurred at a rate of ≥ 2% are summarized in Table 6. Incidence of AEs Occurring in ≥2% of Subjects Presented in Descending Frequency of Preferred Term .
| Adverse Event | Placebo (n = 108) | Estradiol 0.05 mg/day (n = 113) | Estradiol 0.10 mg/day (n = 112) |
| n (%) | n (%) | n (%) | |
| Headache (NOS) | 10 (9.3) | 8 (7.1) | 11 (9.8) |
| Intermenstrual Bleeding | 2 (1.9) | 9 (8.0) | 11 (9.8) |
| Vaginal Candidiasis | 3 (2.8) | 7 (6.2) | 12 (10.7) |
| Breast Tenderness | 2 (1.9) | 7 (6.2) | 12 (10.7) |
| Back Pain | 4 (3.7) | 7 (6.2) | 4 (3.6) |
| Genital Disorder Female (NOS) | 9 (8.3) | 3 (2.7) | 3 (2.7) |
| Upper Respiratory Tract Infection (NOS) | 6 (5.6) | 5 (4.4) | 4 (3.6) |
| Abdominal Distension | 3 (2.8) | 8 (7.1) | 3 (2.7) |
| Vaginal discharge | 9 (8.3) | 2 (1.8) | 3 (2.7) |
| Vulvovaginitis (NOS) | 7 (6.5) | 6 (5.3) | 1 (0.9) |
| Nausea | 5 (4.6) | 3 (2.7) | 2 (1.8) |
| Arthralgia | 4 (3.7) | 2 (1.8) | 2 (1.8) |
| Sinusitis (NOS) | 2 (1.9) | 2 (1.8) | 4 (3.6) |
| Uterine Pain | 1 (0.9) | 2 (1.8) | 5 (4.5) |
| Nasopharyngitis | 3 (2.8) | 2 (1.8) | 2 (1.8) |
| Pain in Limb | 3 (2.8) | 1 (0.9) | 3 (2.7) |
| Urinary Tract Infection (NOS) | 2 (1.9) | 1 (0.9) | 4 (3.6) |
| Vaginal Irritation | 4 (3.7) | 1 (0.9) | 2 (1.8) |
AE = adverse event; NOS = not otherwise specified
The following additional adverse reactions have been reported with estrogens and/or progestin therapy.
1. Genitourinary system
Changes in vaginal bleeding pattern and abnormal withdrawal bleeding or flow; breakthrough bleeding; spotting; dysmenorrhea; increase in size of uterine leiomyomata; change in amount of cervical secretion; changes in cervical ectropion; ovarian cancer; endometrial hyperplasia; endometrial cancer.
2. Breasts
Enlargement, pain, nipple discharge, galactorrhea; fibrocystic breast changes; breast cancer.
3. Cardiovascular
Deep and superficial venous thrombosis; pulmonary embolism; thrombophlebitis; myocardial infarction; stroke; increase in blood pressure.
4. Gastrointestinal
Nausea, vomiting, abdominal cramps, bloating; cholestatic jaundice; increased incidence of gallbladder disease; pancreatitis; enlargement of hepatic hemangiomas.
5. Skin
Chloasma or melasma which may persist when drug is discontinued; erythema multiforme; erythema nodosum; hemorrhagic eruption; loss of scalp hair; hirsutism; pruritis, rash.
6. Eyes
Retinal vascular thrombosis; intolerance to contact lenses.
7. Central nervous system
Headache, migraine; dizziness; mental depression; chorea; nervousness; mood disturbances; irritability; exacerbation of epilepsy; dementia.
8. Miscellaneous
Increase or decrease in weight; reduced carbohydrate tolerance; aggravation of porphyria; edema; leg cramps; changes in libido; urticaria, angioedema, anaphylactoid/anaphylactic reactions; hypocalcemia; exacerbation of asthma; increased triglycerides.
Serious ill effects have not been reported following acute ingestion of large doses of estrogen-containing drug products by young children. Overdosage of estrogen may cause nausea and vomiting, and withdrawal bleeding may occur in females.
When estrogen is prescribed for a postmenopausal woman with a uterus, a progestin should also be initiated to reduce the risk of endometrial cancer. A woman without a uterus does not need progestin. Use of estrogen, alone or in combination with a progestin, should be with the lowest effective dose and for the shortest duration consistent with treatment goals and risks for the individual woman. Patients should be reevaluated periodically as clinically appropriate (e.g., 3-month to 6-month intervals) to determine if treatment is still necessary (see BOXED WARNINGS and WARNINGS). For women who have a uterus, adequate diagnostic measures, such as endometrial sampling, when indicated, should be undertaken to rule out malignancy in cases of undiagnosed persistent or recurring abnormal vaginal bleeding.
Two doses of Femring are available, 0.05 mg/day and 0.10 mg/day, for the treatment of moderate to severe vasomotor symptoms and/or moderate to severe symptoms of vulvar and vaginal atrophy associated with the menopause.
Patients should be started at the lowest dose. The lowest effective dose of Femring has not been determined.
Instructions for Use
Hands should be thoroughly washed before and after ring insertion.
Femring Insertion
Insert upon removal from the protective pouch.
The opposite sides of the vaginal ring should be pressed together and inserted into the vagina. The exact position is not critical to its function. When Femring is in place, the patient should not feel anything. If the patient feels discomfort, the vaginal ring is probably not far enough inside the vagina. Gently push Femring further into the vagina.
Femring Use
Femring should remain in place for 3 months and then be replaced by a new Femring.
The patient should not feel Femring when it is in place and it should not interfere with sexual intercourse. Straining upon bowel movement may make Femring move down in the lower part of the vagina. If so, it may be repositioned with a finger.
If Femring is expelled totally from the vagina, it should be rinsed in lukewarm water and reinserted by the patient (or healthcare provider if necessary).
Femring Removal
Femring may be removed by looping a finger through the ring and pulling it out.
For patient instructions, see PATIENT INFORMATION.
Each Femring® (estradiol acetate vaginal ring) is individually packaged in a pouch consisting of one side medical grade paper and the other side polyester/polyethylene laminate.
NDC 0430-6201-40 Femring® 0.05 mg/day (estradiol acetate vaginal ring) is available in single units.
NDC 0430-6202-40 Femring® 0.10 mg/day (estradiol acetate vaginal ring) is available in single units.
Keep out of reach of children.
STORAGE
Store at 25˚ C (77˚ F); excursions permitted to 15˚ - 30˚ C (59˚ - 86˚ F) [see USP Controlled Room Temperature]
Manufactured by: Warner Chilcott UK Ltd., Larne, Northern Ireland, UK
Marketed by: Warner Chilcott (US), Inc., Rockaway, NJ 07866
6201G014
REVISED February 2007
(Updated February 2007)
Femring® (estradiol acetate vaginal ring)
Read this PATIENT INFORMATION before you start using Femring® and read what you get each time you refill your Femring prescription. There may be new information. This information does not take the place of talking to your healthcare provider about your medical condition or your treatment.