Medroxyprogesterone acetate (MPA) administered orally or parenterally in the recommended doses to women with adequate endogenous estrogen, transforms proliferative into secretory endometrium. Androgenic and anabolic effects have been noted, but the drug is apparently devoid of significant estrogenic activity. While parenterally administered MPA inhibits gonadotropin production, which in turn prevents follicular maturation and ovulation, available data indicate that this does not occur when the usually recommended oral dosage is given as single daily doses.
Pharmacokinetics
The pharmacokinetics of MPA were determined in 20 postmenopausal women following a single-dose administration of eight Medroxyprogesterone acetate 2.5 mg tablets or a single administra- tion of two Medroxyprogesterone acetate 10 mg tablets under fasting conditions. In another study, the steady-state pharmacokinetics of MPA were determined under fasting conditions in 30 post- menopausal women following daily administration of one Medroxyprogesterone acetate 10 mg tablet for 7 days. In both studies, MPA was quantified in serum using a validated gas chroma- tography-mass spectrometry (GC-MS) method. Estimates of the pharmacokinetic parameters of MPA after single and multiple doses of Medroxyprogesterone acetate tablets were highly variable and are summarized in Table 1.
Table 1. Mean (SD) Pharmacokinetic Parameters for Medroxyprogesterone Acetate (MPA)
|
Tablet
Strength |
Cmax
(ng/mL) |
Tmax
(h) |
Auc0-(∞)
(ng·h/mL) |
t½
(h) |
Vd/f
(L) |
CL/f
(mL/min) |
| Single Dose |
| 2 x 10 mg |
1.01 (0.599) |
2.65 (1.41) |
6.95 (3.39) |
12.1 (3.49) |
78024
(47220) |
64110
(42662) |
| 8 x 2.5 mg |
0.805 (0.413) |
2.22 (1.39) |
5.62 (2.79) |
11.6 (2.81) |
62748
(40146) |
74123
(35126) |
| Multiple Dose |
| 10 mg |
0.71 (0.35) |
2.83 (1.83) |
6.01 (3.16) |
16.6
(15) |
40564
(38256) |
41963
(38402) |
A. AbsorptionNo specific investigation on the absolute bioavailability of MPA in humans has been conducted. MPA is rapidly absorbed from the gastrointestinal tract, and maximum MPA concentrations are obtained between 2 to 4 hours after oral administration.
Administration of Medroxyprogesterone acetate with food increases the bioavailability of MPA. A 10 mg dose of Medroxyprogesterone acetate, taken immediately before or after a meal, in- creased MPA Cmax (50 to 70%) and AUC (18 to 33%). The half-life of MPA was not changed with food.
B. DistributionMPA is approximately 90% protein bound, primarily to albumin; no MPA binding occurs with sex hormone binding globulin.
C. MetabolismFollowing oral dosing, MPA is extensively metabolized in the liver via hydroxylation, with subsequent conjugation and elimination in the urine.
D. ExcretionMost MPA metabolites are excreted in the urine as glucuronide conjugates with only minor amounts excreted as sulfates.
E. Special Populations Renal Insufficiency
The pharmacokinetics of MPA in patients with varying degrees of renal insufficiency have not been investigated.
Hepatic Insufficiency
MPA is almost exclusively eliminated via hepatic metabolism. In 14 patients with advanced liver disease, MPA disposition was significantly altered (reduced elimination). In patients with fatty liver, the mean percent dose excreted in the 24-hour urine as intact MPA after a 10 mg or 100 mg dose was 7.3% and 6.4%, respectively.
F. Drug InteractionsNo formal pharmacokinetic drug interaction studies have been conducted with Medroxyprogesterone acetate.
Clinical Studies
Effects on the Endometrium
In a 3-year, double-blind, placebo-controlled study of 356 nonhysterectomized, postmenopausal women between 45 and 64 years of age randomized to receive placebo (n=119), 0.625 mg conjugated estrogen only (n=119), or 0.625 mg conjugated estrogen plus cyclic Medroxyprogesterone acetate (n=118), results showed a reduced risk of endometrial hyperplasia in the treatment group receiving 10 mg Medroxyprogesterone acetate plus 0.625 mg conjugated estrogens compared to the group receiving 0.625 mg conjugated estrogens only. See Table 2.
Table 2. Number (%) of Endometrial Biopsy Changes Since Baseline After 3 Years of Treatment*
| * Includes most extreme abnormal result |
|
Histological
Results |
Placebo
(n=119) |
CEE
(n=119) |
Medroxyprogesterone
Acetate
+ CEE
(n=118) |
Normal/No hyperplasia (%)
|
116 (97) |
45 (38) |
112 (95) |
Simple (cystic) hyperplasia (%)
|
1 (1) |
33 (28) |
4 (3) |
Complex (adenomatous) hyperplasia (%)
|
1 (1) |
27 (22) |
2 (2) |
Atypia (%)
|
0 |
14 (12) |
0 |
Adenocarcinoma (%)
|
1 (1) |
0 |
0 |
In a second 1-year study, 832 postmenopausal women between 45 and 65 years of age were treated with daily 0.625 mg conjugated estrogen (days 1 to 28), plus either 5 mg cyclic Medroxyprogesterone acetate or 10 mg cyclic Medroxyprogesterone acetate (days 1 5to 28), or daily 0.625 mg conjugated estrogen only. The treatment groups receiving 5 or 10 mg cyclic Medroxyprogesterone acetate (days 15 to 28) plus daily conjugated estrogens showed a significantly lower rate of hyperplasia as compared to the conjugated estrogens only group. See Table 3.
Table 3. Number (%) of Women with Endometrial Hyperplasia at 1 Year
|
|
CEE |
MPA + CEE* |
|
(n=283) |
MPA 5 mg
(n=277) |
MPA 10 mg
(n=272) |
Cystic hyperplasia (%)
|
55 (19) |
3 (1) |
0 |
Adenomatous hyperplasia without
atypia |
2 (1) |
0 |
0 |
Women’s Health Initiative Studies
The Women’s Health Initiative (WHI) enrolled approximately 27,000 predominantly healthy postmenopausal women in two substudies to assess the risks and benefits of either the use of daily oral conjugated estrogens (CE 0.625 mg) alone or in combination with Medroxyprogesterone acetate (MPA 2.5 mg) 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 the CE/MPA substudy), 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 plus progestin substudy was 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 (relative risk [RR] 1.15, 95 percent, nominal confidence interval [nCI], 1.03 to 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 6 more CHD events, 7 more strokes, 10 more PEs, and 8 more invasive breast cancers, while the absolute risk reduction per 10,000 women-years were 7 fewer colorectal cancers and 5 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 percent White, 6.8 percent Black, 5.4 percent Hispanic, 3.9 percent Other) are presented in Table 4. These results reflect centrally adjudicated data after an average follow-up of 5.6 years.
Table 4: RELATIVE AND ABSOLUTE RISK SEEN IN THE ESTROGEN PLUS PROGESTIN SUBSTUDY OF WHI AT AN AVERAGE OF 5.6 YEARS
|
Event |
Relative Risk CE/MPA vs placebo
(95% nCI) |
Placebo
n = 8102 |
CE/MPA
n = 8506 |
| Absolute Risk per 10,000 Women-Years |
CHD events
Non-fatal MI
CHD death |
1.24 (1.00-1.54)
1.28 (1.00-1.63)
1.10 (0.70-1.75) |
33
25
8 |
39
31
8 |
| All strokes |
1.31 (1.02-1.68) |
24 |
31 |
| Ischemic stroke |
1.44 (1.09-1.90) |
18 |
26 |
| Deep vein thrombosis |
1.95 (1.43-2.67) |
13 |
26 |
| Pulmonary embolism |
2.13 (1.45-3.11) |
8 |
18 |
| Invasive breast cancer† |
1.24 (1.01-1.54) |
33 |
41 |
| Invasive colorectal cancer |
0.56 (0.38-0.81) |
16 |
9 |
| Endometrial cancer |
0.81 (0.48-1.36) |
7 |
6 |
| Cervical Cancer |
1.44 (0.47-4.42) |
1 |
2 |
| Hip fracture |
0.67 (0.47-0.96) |
16 |
11 |
| Vertebral fractures |
0.65 (0.46-0.92) |
17 |
11 |
| Lower arm/wrist fractures |
0.71 (0.59-0.85) |
62 |
44 |
| Total fractures |
0.76 (0.69-0.83) |
199 |
152 |
Women's Health Initiative Memory Study
The estrogen plus progestin Women’s Health Initiative Memory Study (WHIMS), a substudy of WHI, enrolled 4,532 predominantly healthy postmenopausal women 65 years of age and older (47 percent were aged 65 to 69 years, 35 percent were 70 to 74 years, and 18 percent were 75 years of age and older) to evaluate the effects of daily conjugated estrogens (CE 0.625 mg) plus Medroxyprogesterone acetate (MPA 2.5 mg) on the incidence of probable dementia (primary outcome) compared with placebo.
After an average follow-up of 4 years, 40 women in the estrogen plus 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 percent CI, 1.21 to 3.48) compared to placebo.
Indications and Usage for Medroxyprogesterone
Medroxyprogesterone Acetate Tablets USP are a progestin indicated for the treatment of secondary amenorrhea and abnormal uterine bleeding due to hormonal imbalance in the absence of organic pathology, such as fibroids or uterine cancer. Medroxyprogesterone Acetate Tablets USP are also indicated to reduce the incidence of endometrial hyperplasia in nonhysterectomized postmenopausal women receiving daily oral conjugated estrogens 0.625 mg tablets.
Contraindications
Medroxyprogesterone Acetate Tablets USP should not be used in women with any of the following conditions:
- Undiagnosed abnormal genital bleeding.
- Known, suspected, or history of cancer of the breast.
- Known or suspected estrogen- or progesterone-dependent neoplasia.
- Active deep vein thrombosis, pulmonary embolism or a history of these conditions.
- Active or recent (within the past year) arterial thromboembolic disease (for example, stroke and myocardial infarction).
- Known liver dysfunction or disease.
- Missed abortion.
- As a diagnostic test for pregnancy.
- Known hypersensitivity to the ingredients in Medroxyprogesterone acetate tablets.
- Known or suspected pregnancy.
Warnings
See BOXED WARNINGS.
1. Cardiovascular Disorders.
An increased risk of stroke, deep vein thrombosis (DVT), pulmonary embolism, and myocardial infarction has been reported with estrogen plus progestin therapy. Should any of these events occur or be suspected, estrogen plus progestin therapy should be discontinued immediately.
Risk factors for arterial vascular disease (for example, hypertension, diabetes mellitus, tobacco use, hypercholesterolemia, and obesity) and/or venous thromboembolism (for example, personal history or family history of venous thromboembolism [VTE]), obesity, and systemic lupus erythematosus should be managed appropriately.
a. StrokeIn the estrogen plus progestin substudy of the Women’s Health Initiative (WHI) a statistically significant increased risk of stroke was reported in women receiving daily conjugated estrogens (CE 0.625 mg) plus Medroxyprogesterone acetate (MPA 2.5 mg) compared to women receiving placebo (31 versus 24 per 10,000 women-years). The increase in risk was demonstrated after the first year and persisted. (See CLINICAL STUDIES.)
b. Coronary heart diseaseIn the estrogen plus progestin substudy of WHI, no statistically significant increase of CHD events (defined as non-fatal myocardial infarction [MI], silent MI or CHD death was reported in women receiving CE/MPA compared to women receiving placebo (39 versus 33 per 10,000 women-years). An increase in relative risk was demonstrated in year one, and a trend toward decreasing relative risk was reported in years 2 through 5. (See CLINICAL STUDIES.)
In postmenopausal women with documented heart disease (n = 2,763, average age 66.7 years), in a controlled clinical trial of secondary prevention of cardiovascular disease (Heart and Estro- gen/Progestin Replacement Study [HERS]), treatment with daily CE 0.625 mg/ MPA 2.5 mg per day demonstrated no cardiovascular benefit. During an average follow-up of 4.1 years, treatment with CE/MPA did not reduce the overall rate of CHD events in postmenopausal women with established coronary heart disease. There were more CHD events in the CE/MPA-treated group than in the placebo group in year 1, but not during the subsequent years. Two thousand three hundred and twenty one (2,321) women from the original HERS trial agreed to participate in an open label extension of HERS, HERS II. Average follow-up in HERS II was an additional 2.7 years, for a total of 6.8 years overall. Rates of CHD events were comparable among women in the CE/MPA group and the placebo group in HERS, HERS II, and overall.
c. Venous thromboembolism (VTE)In the estrogen plus progestin substudy of WHI, a statistically significant two-fold greater rate of VTE, (DVT and pulmonary embolism [PE]), was reported in women receiving daily CE/MPA compared to women receiving placebo (35 versus 17 per 10,000 women-years). Statistically significant increases in risk for both DVT (26 versus 13 per 10,000 women-years) and PE (18 versus 8 per 10,000 women-years) were also demonstrated. The increase in VTE risk was observed during the first year and persisted. (See CLINICAL STUDIES.)
2. Malignant Neoplasms
a. Breast cancerThe use of estrogens and progestins by postmenopausal women has been reported to increase the risk of breast cancer in some studies. Observational studies have also reported an increased risk of breast cancer for estrogen plus progestin therapy, and a smaller increased risk for estrogen alone therapy, after several years of use. The risk increased with duration of use and appeared to return to baseline in about 5 years after stopping treatment (only the observational studies have substantial data on risk after stopping). Observational studies also suggest that the risk of breast cancer was greater, and became apparent earlier, with estrogen plus progestin therapy as compared to estrogen alone therapy. However, these studies have not found significant variation in the risk of breast cancer among different estrogens or among different estrogen plus progestin combinations, doses, or routes of administration.
The most important randomized clinical trial providing information about this issue is the Women’s Health Initiative (WHI) substudy of daily conjugated estrogens (CE 0.625 mg) plus Medroxyprogesterone acetate (MPA 2.5 mg) (See CLINICAL STUDIES.)
In the estrogen plus progestin substudy of WHI, after a mean follow-up of 5.6 years, the WHI substudy reported an increased risk of breast cancer in women who took daily CE/MPA. In this substudy, prior use of estrogen alone or estrogen plus progestin therapy was reported by 26 percent of the women. The relative risk of invasive breast cancer was 1.24 (95 percent nominal confidence interval [nCI], 1.01 to 1.54), and the absolute risk was 41 versus 33 cases per 10,000 women-years, for estrogen plus progestin compared with placebo, respectively. Among women who reported prior use of hormone therapy, the relative risk of invasive breast cancer was 1.86, and the absolute risk was 46 versus 25 cases per 10,000 women-years, for CE/MPA compared with placebo. Among women who reported no prior use of hormone therapy, the relative risk of invasive breast cancer was 1.09, and the absolute risk was 40 versus 36 cases per 10,000 women-years, for estrogen plus progestin compared with placebo. In the same substudy, invasive breast cancers were larger and diagnosed at a more advanced stage in the CE/MPA group compared with the placebo group. Metastatic disease was rare with no apparent difference between the two groups. Other prognostic factors such as histologic subtype, grade, and hormone receptor status did not differ between the groups.
The use of estrogen plus progestin has been reported to result in an increase in abnormal mammograms requiring further evaluation. All women should receive yearly breast examinations by a health care provider and perform monthly breast self-examinations. In addition, mammography examinations should be scheduled based on patient age, risk factors, and prior mammogram results.
b. Endometrial cancerAn increased risk of endometrial cancer has been reported with the use of unopposed estrogen therapy in women with a uterus. The reported endometrial cancer risk among unopposed estrogen users is about 2- to 12 times greater than in nonusers, and appears dependent on duration of treatment and on estrogen dose. Most studies show no significant increased risk associated with the use of estrogens for less than 1 year. The greatest risk appears associated with prolonged use, with increased risks of 15- to 24-fold for 5 to 10 years or more. This risk has been shown to persist for at least 8 to 15 years after estrogen therapy is discontinued.
Clinical surveillance of all women using estrogen plus progestin therapy is important. Adequate diagnostic measures, including endometrial sampling when indicated, should be undertaken to rule out malignancy in all cases of undiagnosed persistent or recurring abnormal vaginal bleeding. There is no evidence that the use of natural estrogens results in a different endometrial risk profile than synthetic estrogens of equivalent estrogen dose. Adding a progestin to estrogen therapy has been shown to reduce the risk of endometrial hyperplasia, which may be a precursor to endometrial cancer.
c. Ovarian cancerThe estrogen plus progestin substudy of WHI reported that daily CE/MPA increased the risk of ovarian cancer. After an average follow-up of 5.6 years, the relative risk for ovarian cancer for CE/MPA versus placebo was 1.58 (95 percent nCI, 0.77 to 3.24) but was not statistically significant. The absolute risk for CE/MPA was 4.2 versus 2.7 cases per 10,000 women-years.
3. Dementia
In the estrogen plus progestin Women’s Health Initiative Memory Study (WHIMS), a substudy of WHI, a population of 4,532 postmenopausal women aged 65 to 79 years was randomized to daily conjugated estrogens (CE 0.625 mg) plus Medroxyprogesterone acetate (MPA 2.5 mg) or placebo.
After an average follow-up of 4 years, 40 women in the CE/MPA group and 21 women in the placebo group were diagnosed with probable dementia. The relative risk of probable dementia for CE/MPA versus placebo was 2.05 (95 percent CI, 1.21 to 3.48). The absolute risk of probable dementia for CE/MPA versus placebo was 45 versus 22 cases per 10,000 women-years. It is unknown whether these findings apply to younger postmenopausal women. (See BOXED WARNINGS and PRECAUTIONS, Geriatric Use.)
4. Visual Abnormalities
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, medication should be permanently discontinued.
Precautions
A. General
- 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 (lowering HDL, raising LDL) and impairment of glucose tolerance.
- Undiagnosed abnormal vaginal bleeding
In cases of undiagnosed abnormal vaginal bleeding, adequate diagnostic measures are indicated.
- Elevated blood pressure
Blood pressure should be monitored at regular intervals with estrogen plus progestin therapy.
- Hypertriglyceridemia
In patients with pre-existing hypertriglyceridemia, estrogen plus progestin therapy may be associated with elevations of plasma triglycerides leading to pancreatitis and other complications.
- Impaired liver function and past history of cholestatic jaundice
Estrogens plus progestins 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.
- Fluid Retention
Progestins may cause some degree of fluid retention. Patients who have conditions which might be influenced by this factor, such as cardiac or renal dysfunction, warrant careful observation when estrogen plus progestin are prescribed.
- Hypocalcemia
Estrogen plus progestin therapy should be used with caution in individuals with severe hypocalcemia.
- Exacerbation of other conditions
Estrogen plus progestin therapy may cause an exacerbation of asthma, diabetes mellitus, epilepsy, migraine, porphyria, systemic lupus erythematosus, and hepatic hemangiomas and should be used with caution in women with these conditions.
B. Patient Information
Physicians are advised to discuss the Patient Information leaflet with patients for whom they prescribe Medroxyprogesterone acetate.
There may be an increased risk of minor birth defects in children whose mothers are exposed to progestins during the first trimester of pregnancy. The possible risk to the male baby is hypospadias, a condition in which the opening of the penis is on the underside rather than the tip of the penis. This condition occurs naturally in approximately 5 to 8 per 1,000 male births. The risk may be increased with exposure to Medroxyprogesterone acetate. Enlargement of the clitoris and fusion of the labia may occur in female babies. However, a clear association between hypospadias, clitoral enlargement and labial fusion with use of Medroxyprogesterone acetate has not been established.
Inform the patient of the importance of reporting exposure to Medroxyprogesterone acetate in early pregnancy.
C. Drug/Laboratory Test Interactions
The following laboratory results may be altered by the use of estrogen plus progestin therapy:
- 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 anti-factor Xa and antithrombin III, decreased antithrombin III activity; increased levels of fibrinogen and fibrinogen activity; increased plasminogen antigen and activity.
- 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. Patients on thyroid replacement therapy may require higher doses of thyroid hormone.
- Other binding proteins may be elevated in serum (i.e., corticosteroid binding globulin (CBG), sex hormone binding globulin (SHBG) leading to increased circulating corticosteroid and sex steroids, respectively. Free or biologically active hormone concentrations are unchanged. Other plasma proteins may be increased (angiotensinogen/renin substrate, alpha-1-antitrypsin, ceruloplasmin).
- Increased plasma HDL and HDL2 cholesterol subfraction concentrations, reduced LDL cholesterol concentration, increased triglycerides levels.
- Impaired glucose metabolism.
D. Carcinogenesis, Mutagenesis, Impairment of Fertility
Long-term intramuscular administration of Medroxyprogesterone acetate has been shown to produce mammary tumors in beagle dogs. There was no evidence of a carcinogenic effect associated with the oral administration of Medroxyprogesterone acetate to rats and mice. Medroxyprogesterone acetate was not mutagenic in a battery of in vitro or in vivo genetic toxicity assays.
Medroxyprogesterone acetate at high doses is an antifertility drug and high doses would be expected to impair fertility until the cessation of treatment.
Long-term continuous administration of estrogen plus progestin therapy, has shown an increased risk of breast cancer and ovarian cancer. (See WARNINGS and PRECAUTIONS.)
E. Pregnancy
Teratogenic Effects Pregnancy Category X
Medroxyprogesterone acetate should not be used during pregnancy. (See CONTRAINDICATIONS.)
There may be increased risks for hypospadias, clitoral enlargement and labial fusion in children whose mothers are exposed to Medroxyprogesterone acetate during the first trimester of pregnancy. However, a clear association between these conditions with use of Medroxyprogesterone acetate has not been established.
F. Nursing Mothers
Medroxyprogesterone acetate should not be used during lactation. Detectable amounts of progestin have been identified in the milk of nursing mothers receiving progestins.
G. Pediatric Use
Medroxyprogesterone acetate is not intended for pediatric use and no clinical data has been collected in children.
H. Geriatric Use
Of the total number of subjects in the estrogen plus progestin substudy of the Women’s Health Initiative (WHI), 44 percent (n = 7,320) were 65 years and older, while 6.6 percent (n = 1,095) were 75 years and older. In women 75 and older compared to women less than 75 years of age, there was a higher relative risk of non-fatal stroke and invasive breast cancer in the estrogen plus progestin group versus placebo. In women greater than 75 years of age, the increased risk of non-fatal stroke and invasive breast cancer observed in the estrogen plus progestin group compared to placebo was 75 versus 24 per 10,000 women-years and 52 versus 12 per 10,000 women-years, respectively.
In the estrogen plus progestin Women’s Health Initiative Memory Study (WHIMS), a substudy of WHI, a population of 4,532 postmenopausal women, aged 65 to 70 years, was randomized to receive daily CE 0.625 mg/MPA 2.5 mg or placebo. In the estrogen plus progestin group, after an average follow-up of 4 years, the relative risk (CE/MPA versus placebo) of probable dementia was 2.05 (95 percent CI, 1.21 to 3.48). The absolute risk of developing probable dementia with CE/MPA was 45 versus 22 cases per 10,000 women-years compared with placebo.
Eighty-two percent of the cases of probable dementia occurred in women that were older than 70 in the CE/MPA group. The most common classification of probable dementia in the estrogen plus progestin and placebo groups was Alzheimer’s disease.
When data from the estrogen alone and estrogen plus progestin WHIMS substudies were pooled as planned in the WHIMS protocol, the reported overall relative risk for probable dementia was 1.76 (95 percent CI, 1.19 to 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, Dementia.)
ADVERSE REACTIONS
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.
The following adverse reactions have been reported in women taking progestins, including Medroxyprogesterone acetate tablets, without concomitant estrogens treatment:
1. Genitourinary System
Abnormal uterine bleeding (irregular, increase, decrease), change in menstrual flow, breakthrough bleeding, spotting, amenorrhea, changes in cervical erosion and cervical secretions.
2. Breasts
Breast tenderness, mastodynia or galactorrhea has been reported.
3. Cardiovascular
Thromboembolic disorders including thrombophlebitis and pulmonary embolism have been reported.
4. Gastrointestinal
Nausea, cholestatic jaundice.
5. Skin
Sensitivity reactions consisting of urticaria, pruritus, edema and generalized rash have occurred. Acne, alopecia and hirsutism have been reported.
6. Eyes
Neuro-ocular lesions, for example, retinal thrombosis, and optic neuritis.
7. Central Nervous System
Mental depression, insomnia, somnolence, dizziness, headache, nervousness.
8. Miscellaneous
Hypersensitivity reactions (for example, anaphylaxis and anaphylactoid reactions, angioedema), rash (allergic) with and without pruritus, change in weight (increase or decrease), pyrexia, edema/fluid retention, fatigue, decreased glucose tolerance.
The following additional adverse reactions have been reported with estrogen and/or progestin therapy.
1. Genitourinary System
Abnormal uterine bleeding/spotting, or flow; breakthrough bleeding; spotting; dysmenorrheal/pelvic pain; increase in size of uterine leiomyomata; vaginitis, including vaginal candidiasis; change in amount of cervical secretion; changes in cervical ectropion; ovarian cancer; endometrial hyperplasia; endometrial cancer.
