Does Femara (letrozole) cause side effects?

Femara (letrozole) is an anti-estrogen drug that is used to treat postmenopausal women with breast cancer

The growth of some breast cancers in postmenopausal women is promoted by estrogens that circulate in the blood, and the adrenal glands are the main source of these circulating estrogens. Femara inhibits the enzyme in the adrenal glands (aromatase) that produces the estrogens, estradiol and estrone. 

Common side effects of Femara include

Serious side effects of Femara include

Drug interactions of Femara include tamoxifen, which reduces blood levels of Femara when both drugs are administered together. However, in clinical studies the benefit of Femara was not reduced when administered immediately after tamoxifen. 

Femara is an anti-estrogen drug. Therefore, estrogen containing products counteract the effect of Femara. 

Femara damages a fetus. It should not be taken by pregnant women. It is unknown if Femara is secreted into breast milk. Consult your doctor before breastfeeding.

What are the important side effects of Femara (letrozole)?

The most common side effects with letrozole are:

Cholesterol levels may increase during letrozole therapy. Cholesterol levels should be monitored and some patients may require treatment for high cholesterol levels. Letrozole decreases bone mineral density, increasing the risk of osteoporosis and fractures.

Femara (letrozole) side effects list for healthcare professionals

The following adverse reactions are discussed in greater detail in other sections of the labeling.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reactions 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.

Adjuvant Treatment Of Early Breast Cancer
  • In study, BIG 1-98, the median treatment duration of adjuvant treatment was 60 months and the median duration of follow-up for safety was 96 months for patients receiving Femara and tamoxifen.
  • Certain adverse reactions were prospectively specified for analysis (see Table 1), based on the known pharmacologic properties and side effect profiles of the two drugs.
  • Adverse reactions were analyzed irrespective of whether a symptom was present or absent at baseline.
  • Most adverse reactions reported (approximately 75% of patients who reported AEs) were
    • Grade 1 or Grade 2 applying the Common Toxicity Criteria (CTC) Version 2.0/Common Terminology Criteria for Adverse Events (CTCAE),
    • Version 3.0. Table 1 describes adverse reactions (Grades 1-4 and Grades 3-4) irrespective of relationship to study treatment in the adjuvant trial for the monotherapy arms analysis (safety population).

Table 1: Patients with Adverse Reactions (CTC Grades 1-4,) in the Adjuvant Study – Monotherapy Arms Analysis (Median Follow-up 96 Months; Median Treatment 60 Months)

Adverse ReactionsGrades 1-4Grades 3-4
Femara
N = 2448
n (%)
Tamoxifen
N = 2447
n (%)
Femara
N = 2448
n (%)
Tamoxifen
N = 2447
n (%)
Patients with any adverse reaction2309(94.3)2212(90.4)636(26.0)606(24.8)
Hypercholesterolemia*1280(52.3)700(28.6)11(0.4)6(0.2)
Hot flashes*819(33.5)929(38.0)----
Arthralgia/arthritis*621(25.4)504(20.6)84(3.4)50(2.0)
Bone fractures1361(14.7)280(11.4)----
Night sweats*356(14.5)426(17.4)----
Weight increase*317(12.9)378(15.4)27(1.1)39(1.6)
Nausea*284(11.6)277(11.3)6(0.2)9(0.4)
Bone fractures**2249(10.2)175(7.2)----
Fatigue (lethargy, malaise, asthenia)*235(9.6)250(10.2)6(0.2)7(0.3)
Myalgia*221(9.0)212(8.7)18(0.7)14(0.6)
Vaginal bleeding*129(5.3)320(13.1)1(< 0.1)8(0.3)
Edema*164(6.7)160(6.5)3(0.1)1(< 0.1)
Weight decrease140(5.7)129(5.3)8(0.3)5(0.2)
Osteoporosis**126(5.1)67(2.7)10(0.4)5(0.2)
Back pain125(5.1)136(5.6)7(0.3)11(0.4)
Bone pain123(5.0)109(4.5)6(0.2)4(0.2)
Depression119(4.9)114(4.7)16(0.7)14(0.6)
Vaginal irritation*112(4.6)77(3.1)2(< 0.1)2(< 0.1)
Headache*105(4.3)94(3.8)8(0.3)4(0.2)
Pain in extremity103(4.2)79(3.2)6(0.2)4(0.2)
Osteopenia*87(3.6)76(3.1)0-3(0.1)
Dizziness/light-headedness*84(3.4)80(3.3)1(< 0.1)6(0.2)
Alopecia83(3.4)84(3.4)----
Vomiting*80(3.3)80(3.3)3(0.1)5(0.2)
Cataract*49(2.0)54(2.2)16(0.7)17(0.7)
Constipation*49(2.0)71(2.9)3(0.1)1(< 0.1)
Myocardial infarction142(1.7)28(1.1)----
Breast pain*37(1.5)43(1.8)1(< 0.1)--
Anorexia*20(0.8)20(0.8)1(< 0.1)1(< 0.1)
Endometrial proliferation disorders*14(0.6)86(3.5)0-14(0.6)
Ovarian cyst*11(0.4)18(0.7)4(0.2)4(0.2)
Endometrial hyperplasia/cancer**111(0.4)72(2.9)----
Endometrial hyperplasia/cancer**,36/1909(0.3)57/1943(2.9)----
Other endometrial disorders*2(< 0.1)3(0.1)0-0-
Myocardial infarction**224(1.0)12(0.5)----
Myocardial ischemia6(0.2)9(0.4)----
Cerebrovascular accident/TIA**174(3.0)68(2.8)----
Cerebrovascular accident/TIA**251(2.1)47(1.9)----
Angina requiring surgery**135(1.4)33(1.3)----
Angina requiring surgery**225(1.0)25(1.0)----
Thromboembolic event**179(3.2)113(4.6)----
Thromboembolic event**251(2.1)89(3.6)----
Cardiac failure139(1.6)34(1.4)----
Cardiac failure227(1.1)15(0.6)----
Hypertension1160(6.5)175(7.2)----
Hypertension2138(5.6)139(5.7)----
Other cardiovascular**1172(7.0)174(7.1)----
Other cardiovascular**2120(4.9)119(4.9)----
Second primary malignancy1129(5.3)150(6.1)----
Second primary malignancy254(2.2)79(3.2)----
* Target events pre-specified for analysis
** Events pre-printed on CRF
1At median follow-up of 96 months (i.e. any time after randomization) for Femara (range up to 144 months) and 95 months for tamoxifen (range up to 143 months )
2At median treatment duration of 60 months (i.e. during treatment + 30 days after discontinuation of treatment) for Femara and tamoxifen (range up to 68 months)
3Excluding women who had undergone hysterectomy before study entry
TIA = Transient ischemic attack
Note: Cardiovascular events (including cerebrovascular and thromboembolic events), skeletal and urogenital/endometrial events and second primary malignancies were collected life -long. All of these events were assumed to be of CTC Grade 3 to 5 and were not individually graded

  • When considering all grades during study treatment, a higher incidence of events was seen for Femara regarding
    • fractures (10.1% vs 7.1%),
    • myocardial infarctions (1.0% vs 0.5%), and
    • arthralgia (25.2% vs 20.4%) (Femara vs tamoxifen respectively).
  • A higher incidence was seen for tamoxifen regarding thromboembolic events (2.1% vs 3.6%), endometrial hyperplasia/cancer (0.3% vs 2.9%), and endometrial proliferation disorders (0.3% vs 1.8%) (Femara vs tamoxifen respectively).
  • At a median follow-up of 96 months, a higher incidence of events was seen for Femara (14.7%) than for tamoxifen (11.4%) regarding fractures.
  • A higher incidence was seen for tamoxifen compared to Femara regarding
    • thromboembolic events (4.6% vs 3.2%), and
    • endometrial hyperplasia or cancer (2.9% vs 0.4%) (tamoxifen vs Femara, respectively).
Bone Study
  • Results of a safety trial in 263 postmenopausal women with resected receptor positive early breast cancer in the adjuvant setting comparing the effect on lumbar spine (L2-L4) BMD of adjuvant treatment with letrozole to that with tamoxifen showed at 24 months a median decrease in lumbar spine BMD of 4.1% in the letrozole arm compared to a median increase of 0.3% in the tamoxifen arm (difference = 4.4%) (P < 0.0001).
  • No patients with a normal BMD at baseline became osteoporotic over the 2 years and only 1 patient with osteopenia at baseline (T score of -1.9) developed osteoporosis during the treatment period (assessment by central review).
  • The results for total hip BMD were similar, although the differences between the two treatments were less pronounced.
  • During the 2 year period, fractures were reported by 4 of 103 patients (4%) in the letrozole arm, and 6 of 97 patients (6%) in the tamoxifen arm.
Lipid Study

In a safety trial in 263 postmenopausal women with resected receptor positive early breast cancer at 24 months comparing the effects on lipid profiles of adjuvant letrozole to tamoxifen, 12% of patients on letrozole had at least one total cholesterol value of a higher CTCAE grade than at baseline compared with 4% of patients on tamoxifen.

In another postapproval randomized, multicenter, open label, study of letrozole vs anastrozole in the adjuvant treatment of postmenopausal women with hormone receptor and node positive breast cancer (FACE, NCT00248170), the median duration of treatment was 60 months for both treatment arms. Table 2 describes adverse reactions (Grades 1-4 and Grades 3-4) irrespective of relationship to study treatment in the adjuvant study (safety population).

Table 2: Adverse Reactions (CTC Grades 1-4), Occurring in at least 5% of Patients in Either Treatment Arm, by Preferred Term (Safety set)

Adverse ReactionsLetrozole
N = 2049
n (%)
Anastrozole
N = 2062
n (%)
Grade 3/4
n (%)
All Grades
n (%)
Grade 3/4
n (%)
All Grades
n (%)
Patients with at least one AR628 (30.6)2049 (100.0)591 (28.7)2062 (100.0)
Arthralgia80 (3.9)987 (48.2)69 (3.3)987 (47.9)
Hot flush17 (0.8)666 (32.5)9 (0.4)666 (32.3)
Fatigue8 (0.4)345 (16.8)10 (0.5)343 (16.6)
Osteoporosis5 (0.2)223 (10.9)11 (0.5)225 (10.9)
Myalgia16 (0.8)233 (11.4)15 (0.7)212 (10.3)
Back pain11 (0.5)212 (10.3)17 (0.8)193 (9.4)
Osteopenia4 (0.2)203 (9.9)1 (0.0)173 (8.4)
Pain in extremity9 (0.4)168 (8.2)3 (0.1)174 (8.4)
Lymphoedema5 (0.2)159 (7.8)2 (0.1)179 (8.7)
Insomnia7 (0.3)160 (7.8)3 (0.1)149 (7.2)
Hypercholesterolaemia2 (0.1)155 (7.6)1 (0.0)151 (7.3)
Hypertension25 (1.2)156 (7.6)20 (1.0)149 (7.2)
Depression16 (0.8)147 (7.2)13 (0.6)137 (6.6)
Bone pain10 (0.5)138 (6.7)9 (0.4)122 (5.9)
Nausea6 (0.3)137 (6.7)5 (0.2)152 (7.4)
Headache3 (0.1)130 (6.3)5 (0.2)168 (8.1)
Alopecia2 (0.1)127 (6.2)0 (0.0)134 (6.5)
Musculoskeletal pain6 (0.3)123 (6.0)9 (0.4)147 (7.1)
Radiation skin injury11 (0.5)120 (5.9)6 (0.3)88 (4.3)
Dyspnoea16 (0.8)118 (5.8)10 (0.5)96 (4.7)
Cough1 (0.0)106 (5.2)1 (0.0)120 (5.8)
Musculoskeletal stiffness2 (0.1)102 (5.0)2 (0.1)84 (4.1)
Dizziness2 (0.2)94 (4.6)7 (0.3)109 (5.3)

The following adverse reactions were also identified in less than 5% of the 2049 patients treated with letrozole and not included in the table:

Extended Adjuvant Treatment Of Early Breast Cancer, Median Treatment Duration Of 24 Months

In study MA-17, the median duration of extended adjuvant treatment was 24 months and the median duration of follow-up for safety was 28 months for patients receiving Femara and placebo.

Table 3 describes the adverse reactions occurring at a frequency of at least 5% in any treatment group during treatment. Most adverse reactions reported were Grade 1 and Grade 2 based on the CTC Version 2.0.

In the extended adjuvant setting, the reported drug-related adverse reactions that were significantly different from placebo were

Table 3: Adverse Reactions Occurring in at least 5% of Patients in either Treatment Arm

Number (%) of Patients with Grade 1-4
Adverse Reactions
Number (%) of Patients with Grade 3-4
Adverse Reactions
Femara
N = 2563
Placebo
N = 2573
Femara
N = 2563
Placebo
N = 2573
Any Adverse Reactions2232 (87.1)2174 (84.5)419 (16.3)389 (15.1)
Vascular Disorders1375 (53.6)1230 (47.8)59 (2.3)74 (2.9)
  Flushing1273 (49.7)1114 (43.3)3 (0.1)0
General Disorders1154 (45)1090 (42.4)30 (1.2)28 (1.1)
  Asthenia862 (33.6)826 (32.1)16 (0.6)7 (0.3)
  Edema NOS471 (18.4)416 (16.2)4 (0.2)3 (0.1)
Musculoskeletal Disorders978 (38.2)836 (32.5)71 (2.8)50 (1.9)
  Arthralgia565 (22)465 (18.1)25 (1)20 (0.8)
  Arthritis NOS173 (6.7)124 (4.8)10 (0.4)5 (0.2)
  Myalgia171 (6.7)122 (4.7)8 (0.3)6 (0.2)
  Back Pain129 (5)112 (4.4)8 (0.3)7 (0.3)
Nervous System Disorders863 (33.7)819 (31.8)65 (2.5)58 (2.3)
  Headache516 (20.1)508 (19.7)18 (0.7)17 (0.7)
  Dizziness363 (14.2)342 (13.3)9 (0.4)6 (0.2)
Skin Disorders830 (32.4)787 (30.6)17 (0.7)16 (0.6)
  Sweating Increased619 (24.2)577 (22.4)1 (< 0.1)0
Gastrointestinal Disorders725 (28.3)731 (28.4)43 (1.7)42 (1.6)
  Constipation290 (11.3)304 (11.8)6 (0.2)2 (< 0.1)
  Nausea221 (8.6)212 (8.2)3 (0.1)10 (0.4)
  Diarrhea NOS128 (5)143 (5.6)12 (0.5)8 (0.3)
Metabolic Disorders551 (21.5)537 (20.9)24 (0.9)32 (1.2)
  Hypercholesterolemia401 (15.6)398 (15.5)2 (< 0.1)5 (0.2)
Reproductive Disorders303 (11.8)357 (13.9)9 (0.4)8 (0.3)
  Vaginal Hemorrhage123 (4.8)171 (6.6)2 (< 0.1)5 (0.2)
  Vulvovaginal Dryness137 (5.3)127 (4.9)00
Psychiatric Disorders320 (12.5)276 (10.7)21 (0.8)16 (0.6)
  Insomnia149 (5.8)120 (4.7)2 (< 0.1)2 (< 0.1)
Respiratory Disorders279 (10.9)260 (10.1)30 (1.2)28 (1.1)
  Dyspnea140 (5.5)137 (5.3)21 (0.8)18 (0.7)
Investigations184 (7.2)147 (5.7)13 (0.5)13 (0.5)
Infections and Infestations166 (6.5)163 (6.3)40 (1.6)33 (1.3)
Renal Disorders130 (5.1)100 (3.9)12 (0.5)6 (0.2)

Based on a median follow-up of patients for 28 months,the incidence of clinical fractures from the core randomized study in patients who received Femara was 5.9% (152) and placebo was 5.5% (142).

The incidence of self-reported osteoporosis was higher in patients who received Femara 6.9% (176) than in patients who received placebo 5.5% (141). Bisphosphonates were administered to 21.1% of the patients who received Femara and 18.7% of the patients who received placebo.

The incidence of cardiovascular ischemic events from the core randomized study was comparable between patients who received Femara 6.8% (175) and placebo 6.5% (167).

A patient-reported measure that captures treatment impact on important symptoms associated with estrogen deficiency demonstrated a difference in favor of placebo for vasomotor and sexual symptom domains.

Bone Substudy: See prescribing information.

Lipid Substudy: In the extended adjuvant setting, based on a median duration of follow-up of 62 months, there was no significant difference between Femara and placebo in total cholesterol or in any lipid fraction at any time over 5 years. Use of lipid lowering drugs or dietary management of elevated lipids was allowed.

Updated Analysis, Extended Adjuvant Treatment Of Early Breast Cancer, Median Treatment Duration Of 60 Months
  • The extended adjuvant treatment trial (MA-17) was unblinded early. At the updated (final analysis), overall the side effects seen were consistent to those seen at a median treatment duration of 24 months.
  • During treatment or within 30 days of stopping treatment (median duration of treatment 60 months) a higher rate of fractures was observed for Femara (10.4%) compared to placebo (5.8%), as also a higher rate of osteoporosis (Femara 12.2% vs placebo 6.4%).
  • Based on 62 months median duration of follow-up in the randomized letrozole arm in the safety population the incidence of new fractures at any time after randomization was 13.3% for letrozole and 7.8% for placebo. The incidence of new osteoporosis was 14.5% for letrozole and 7.8% for placebo.
  • During treatment or within 30 days of stopping treatment (median duration of treatment 60 months), the incidence of cardiovascular events was 9.8% for Femara and 7.0% for placebo.
  • Based on 62 months median duration of follow-up in the randomized letrozole arm in the safety population the incidence of cardiovascular disease at any time after randomization was 14.4% for letrozole and 9.8% for placebo.

Lipid substudy

  • In the extended adjuvant setting (MA-17), based on a median duration of follow-up of 62 months, there was no significant difference between Femara and placebo in total cholesterol or in any lipid fraction over 5 years. Use of lipid lowering drugs or dietary management of elevated lipids was allowed.
First-Line Treatment Of Advanced Breast Cancer

In study P025 a total of 455 patients were treated for a median time of exposure of 11 months in the Femara arm (median 6 months in the tamoxifen arm). The incidence of adverse reactions was similar for Femara and tamoxifen.

The most frequently reported adverse reactions were bone pain, hot flushes, back pain, nausea, arthralgia and dyspnea. Discontinuations for adverse reactions other than progression of tumor occurred in 10/455 (2%) of patients on Femara and in 15/455 (3%) of patients on tamoxifen.

Adverse reactions that were reported in at least 5% of the patients treated with Femara 2.5 mg or tamoxifen 20 mg in the first-line treatment study are shown in Table 4.

Table 4: Adverse Reactions Occurring in at least 5% of Patients in either Treatment Arm

Adverse ReactionsFemara
2.5 mg
(N = 455)
%
Tamoxifen
20 mg
(N = 455)
%
General Disorders
  Fatigue1313
  Chest Pain89
  Edema Peripheral56
  Pain NOS57
  Weakness64
Investigations
  Weight Decreased75
Vascular Disorders
  Hot Flushes1916
  Hypertension84
Gastrointestinal Disorders
  Nausea1717
  Constipation1011
  Diarrhea84
  Vomiting78
Infections/Infestations
  Influenza64
  Urinary Tract Infection NOS63
Injury, Poisoning and Procedural Complications
  Post-Mastectomy Lymphedema77
Metabolism and Nutrition Disorders
  Anorexia46
Musculoskeletal and Connective Tissue Disorders
  Bone Pain2221
  Back Pain1819
  Arthralgia1615
  Pain in Limb108
Nervous System Disorders
  Headache NOS87
Psychiatric Disorders
  Insomnia74
Reproductive System and Breast Disorders
  Breast Pain77
Respiratory, Thoracic and Mediastinal Disorders
  Dyspnea1817
  Cough1313
  Chest Wall Pain66

  • Other less frequent (less than or equal to 2%) adverse reactions considered consequential for both treatment groups, included peripheral thromboembolic events, cardiovascular events, and cerebrovascular events.
  • Peripheral thromboembolic events included
  • Cardiovascular events included
  • Cerebrovascular events included
    • transient ischemic attacks,
    • thrombotic or hemorrhagic strokes and
    • development of hemiparesis.
Second-Line Treatment Of Advanced Breast Cancer
  • Study discontinuations in the megestrol acetate comparison study (AR/BC2) for adverse reactions other than progression of tumor were 5/188 (2.7%) on Femara 0.5 mg, in 4/174 (2.3%) on Femara 2.5 mg, and in 15/190 (7.9%) on megestrol acetate.
  • There were fewer thromboembolic events at both Femara doses than on the megestrol acetate arm (0.6% vs 4.7%).
  • There was also less vaginal bleeding (0.3% vs 3.2%) on Femara than on megestrol acetate.
  • In the aminoglutethimide comparison study (AR/BC3), discontinuations for reasons other than progression occurred in 6/193 (3.1%) on 0.5 mg Femara, 7/185 (3.8%) on 2.5 mg Femara, and 7/178 (3.9%) of patients on aminoglutethimide.
  • Comparisons of the incidence of adverse reactions revealed no significant differences between the high and low dose Femara groups in either study.
  • Most of the adverse reactions observed in all treatment groups were mild to moderate in severity and it was generally not possible to distinguish adverse reactions due to treatment from the consequences of the patient’s metastatic breast cancer, the effects of estrogen deprivation, or intercurrent illness.
  • Adverse reactions that were reported in at least 5% of the patients treated with Femara 0.5 mg, Femara 2.5 mg, megestrol acetate, or aminoglutethimide in the two controlled trials AR/BC2 and AR/BC3 are shown in Table 5.

Table 5: Adverse Reactions Occurring at a Frequency of at Least 5% of Patients in Either Treatment Arm

Adverse ReactionsPooled
Femara
2.5 mg
(N = 359)
%
Pooled
Femara
0.5 mg
(N = 380)
%
Megestrol
Acetate
160 mg
(N = 189)
%
Aminoglutethimide
500 mg
(N = 178)
%
Body as a Whole
  Chest Pain6373
  Peripheral Edema15583
  Asthenia4545
  Weight Increase2293
Cardiovascular
  Hypertension5756
Digestive System
  Nausea1315914
  Vomiting7759
  Constipation6797
  Diarrhea6534
  Pain-Abdominal6598
  Anorexia5355
  Dyspepsia3465
Infections/Infestations
  Viral Infection6563
Lab Abnormality
  Hypercholesterolemia3306
Musculoskeletal System
  Musculoskeletal221223014
  Arthralgia8883
Nervous System
  Headache91297
  Somnolence3229
  Dizziness3573
Respiratory System
  Dyspnea79165
  Coughing6575
Skin and Appendages
  Hot Flushes6543
  Rash354312
  Pruritus1253
1Includes peripheral edema, leg edema, dependent edema, edema
2Includes musculoskeletal pain, skeletal pain, back pain, arm pain, leg pain
3Includes rash, erythematous rash, maculopapular rash, psoriasiform rash, vesicular rash

First And Second-Line Treatment Of Advanced Breast Cancer

In the combined analysis of the first- and second-line metastatic trials and postmarketing experiences other adverse reactions that were reported were

  • cataract,
  • eye irritation,
  • palpitations,
  • cardiac failure,
  • tachycardia,
  • dysesthesia (including hypesthesia/paresthesia),
  • arterial thrombosis,
  • memory impairment,
  • irritability,
  • nervousness,
  • urticaria,
  • increased urinary frequency,
  • leukopenia,
  • stomatitis cancer pain,
  • pyrexia,
  • vaginal discharge,
  • appetite increase,
  • dryness of skin and mucosa (including dry mouth), and
  • disturbances of taste and thirst.

Postmarketing Experience

The following adverse reactions have been identified during postapproval use of Femara. 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.

What drugs interact with Femara (letrozole)?

Tamoxifen

Coadministration of Femara and tamoxifen 20 mg daily resulted in a reduction of letrozole plasma levels of 38% on average (study P015). Clinical experience in the second-line breast cancer trials (AR/BC2 and AR/BC3) indicates that the therapeutic effect of Femara therapy is not impaired if Femara is administered immediately after tamoxifen.

Cimetidine

  • A pharmacokinetic interaction study with cimetidine (study P004) showed no clinically significant effect on letrozole pharmacokinetics.

Warfarin

  • An interaction study (P017) with warfarin showed no clinically significant effect of letrozole on warfarin pharmacokinetics.

Other Anticancer Agents

  • There is no clinical experience to date on the use of Femara in combination with other anticancer agents.

Summary

Femara (letrozole) is an anti-estrogen drug that is used to treat postmenopausal women with breast cancer. Common side effects of Femara include nausea, vomiting, fatigue, headache, muscle aches, diarrhea, constipation, and chest pain. Femara is an anti-estrogen drug and causes fetal harm during pregnancy. It is unknown if Femara is secreted into breast milk.

Treatment & Diagnosis

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Medically Reviewed on 11/10/2020
References
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