Tamoxifen Side Effects
It is possible that some side effects of tamoxifen may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.
For the Consumer
Applies to tamoxifen: oral solution, oral tablet
Because of the way this medicine acts on the body, there is a chance that it might cause unwanted effects that may not occur until months or years after the medicine is used. Tamoxifen increases the chance of cancer of the uterus (womb) in some women taking it. Tamoxifen may cause blockages to form in a vein, lung, or brain. In women, tamoxifen may cause cancer or other problems of the uterus (womb). It also causes liver cancer in rats. In addition, tamoxifen has been reported to cause cataracts and other eye problems. Discuss these possible effects with your doctor.
As well as its needed effects, tamoxifen may cause unwanted side effects that require medical attention.
If any of the following side effects occur while taking tamoxifen, check with your doctor immediately:Less common or rare
- blistering, peeling, or loosening of the skin and mucous membranes
- blurred vision
- cataracts in the eyes or other eye problems
- change in vaginal discharge
- chest pain
- fast heartbeat
- lower back or side pain
- pain or feeling of pressure in the pelvis
- pain or swelling in the legs
- pain, redness, or swelling in your arm or leg
- painful or difficult urination
- rapid shallow breathing
- shortness of breath or trouble with breathing
- skin rash or itching over the entire body
- weakness or sleepiness
- vaginal bleeding
- yellow eyes or skin
- darkened urine
- difficulty with breathing
- joint or muscle pain
- large, hard skin blisters
- large hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, and sex organs
- loss of appetite
- pain in the stomach or side, possibly radiating to the back
- red, irritated eyes
- red skin lesions, often with a purple center
- sore throat
- sores, ulcers or white spots in the mouth or on the lips
- unusual tiredness or weakness
Some tamoxifen side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:More common
- Absent, missed, or irregular periods
- decrease in the amount of urine
- feeling of warmth
- menstrual changes
- noisy, rattling breathing
- redness of the face, neck, arms and occasionally, upper chest
- skin changes
- stopping of menstrual bleeding
- swelling of the fingers, hands, feet, or lower legs
- troubled breathing at rest
- weight gain or loss
- white or brownish vaginal discharge
- Abdominal or stomach cramps
- black, tarry stools
- bleeding gums
- blood in the urine or stools
- bluish color changes in skin color
- bone pain
- decreased interest in sexual intercourse
- feeling sad or empty
- hair loss or thinning of the hair
- inability to have or keep an erection
- itching in the genital area
- loss of interest or pleasure
- loss in sexual ability, desire, drive, or performance
- nausea or vomiting (mild)
- pinpoint red spots on the skin
- skin rash or dryness
- stomach or pelvic discomfort, aching, or heaviness
- trouble concentrating
- trouble with sleeping
- unusual bleeding or bruising
For Healthcare Professionals
Applies to tamoxifen: compounding powder, oral solution, oral tablet
In general, hot flashes, nausea, and vomiting have been the most commonly reported adverse effects, occurring in up to 25% of patients.
Oncologic side effects including numerous endometrial abnormalities have been reported with tamoxifen use. These have included both endometrial adenocarcinoma (incidence rate per 1,000 women-years of 2.20 for tamoxifen versus 0.71 for placebo) and uterine sarcoma (incidence rate per 1,000 women-years of 0.17 for tamoxifen versus 0.04 for placebo). In most women treated with tamoxifen, the endometrium remains atrophic. However, hyperplasia, metaplasia, atypical hyperplasia, and endometrial polyps have also been reported.
The National Surgical Adjuvant Breast and Bowel Cancer (NSABP) B-14 trial evaluated the incidence of endometrial cancer in women with node-negative, estrogen receptor-positive, invasive breast cancer randomized to receive either placebo or tamoxifen 20 mg per day for five years after undergoing primary therapy. Compared with the placebo group, the relative risk of endometrial cancer among tamoxifen-treated women was 7.5.
In general, patients should be examined for preexisting endometrial lesions prior to starting tamoxifen therapy. The benefits and timing of routine endometrial screening, after initial scrounge, have yet to be defined. However, any postmenopausal bleeding or abnormal bleeding in premenopausal women should prompt a gynecological evaluation.
Genitourinary side effects including endometriosis, vaginal bleeding, vaginal discharge, amenorrhea, altered menses, and oligomenorrhea have been reported in up to 24% of patients. However, these effects have rarely necessitated dosage reduction or drug withdrawal. Recurrent vulvovaginal candidiasis in postmenopausal women has been associated with long term treatment. Priapism and suppression of spermatogenesis have been reported in male patients treated with tamoxifen.
Musculoskeletal side effects including pain and bone pain or bone "flare" have been reported in some patients following onset of tamoxifen therapy and generally subside rapidly. Severe hypercalcemia or pancytopenia may occur in conjunction with these symptoms. In addition, patients with soft tissue disease may experience an initial increase in lesion size as well as local erythema during initiation of therapy. Other rheumatologic side effects have included a report of an acute, symmetrical inflammatory polyarthropathy.
Metabolic side effects have included severe hypercalcemia. Severe hypertriglyceridemia has been reported in one patient. The drug has been shown to inhibit bone turnover in women over 70 years old.
Life-threatening hypercalcemia may occur during initial therapy with tamoxifen in patients with bone metastases. Monitoring of serum calcium levels during early therapy is recommended for patients in whom bone metastases are present or are suspected. In cases of severe hypercalcemia, discontinuation of tamoxifen may be warranted, with reinstitution at a lower dose once calcium levels have normalized.
Bone mineral density studies have failed to find evidence of increased risk of osteoporosis in women treated with tamoxifen. One study noted a significant reduction in serum osteocalcin and alkaline phosphatase, indicating that tamoxifen may actually decrease the rate of trabecular bone resorption.
Hepatic side effects have included elevation in liver function tests, jaundice, peliosis hepatitis, steatohepatitis, cholestasis, and massive hepatic necrosis. While severe hepatic effects are rare, fatalities have been reported.
Hematologic side effects have been uncommon and have included thrombocytopenia (1%), leukopenia, and agranulocytosis. Two cases of cerebral sinus thrombosis have also been reported. Small, but clinically insignificant, decreases in antithrombin III and fibrinogen have been reported.
A prospective study involving 63 patients evaluated the risk of ocular toxicity due to tamoxifen 20 mg daily for a mean duration of 25 months (range: 6 to 51 months). Ocular toxicity, characterized by decreased visual acuity and retinopathy, occurred in 4 (6.3%) patients. Irreversible subepithelial corneal opacities were noted in one patient. Earlier reports suggested ocular toxicity was only associated with high-dose (>180 mg per day) therapy. However, this study and other recent case reports support a risk with currently accepted dosage regimens.
Ocular side effects including bilateral optic neuritis, retinopathy, and subepithelial opacities have been reported. Several cases of keratopathy have also been reported.
Several studies evaluating the effect of tamoxifen on antithrombin III, fibrinogen, and platelets have been unable to provide clarification of thromboembolic risk in tamoxifen treated patients. In addition, despite its antiestrogenic activity, evidence is lacking to support a tamoxifen-associated increase in cardiovascular risk. One study concluded that tamoxifen and prior surgery, fracture, or immobilization were associated with a significantly increased risk of developing a venous thromboembolism. Another study found a decreased risk of myocardial infarction.
In one study of 8 premenopausal and 46 postmenopausal women with advanced breast cancer, tamoxifen 10 mg three times daily produced no effect on total cholesterol, triglycerides, or free fatty acids. A significant increase in HDL and subsequent increase in HDL/total cholesterol ratio were noted in addition to a significant reduction in LDL cholesterol. Overall, tamoxifen appeared to exert a favorable effect on the lipid profile.
One five year study has reported total serum cholesterol, LDL cholesterol, and lipoprotein to be significantly lower and apolipoprotein A1 levels significantly higher in 30 tamoxifen recipients compared with the 32 patients who did not receive tamoxifen. Apolipoprotein B levels were reported to have increased to a greater extent in the group which did not receive tamoxifen. After five years, fibrinogen level decreases and triglyceride level increases in the tamoxifen group were of borderline statistical significance. In general, the favorable changes in the lipid, lipoprotein, and fibrinogen levels seen early in tamoxifen therapy in postmenopausal women were reported to have continued to be seen five years into the treatment regimen.
Cardiovascular side effects including stroke (incidence rate per 1,000 women years was 1.43 for tamoxifen versus 1.00 for placebo) have been reported. Hot flushes (which may be severe in up to 22.7% of patients), edema (25%), phlebitis (1%), and thromboembolism have also been reported.
Respiratory side effects including pulmonary embolism (incidence rate per 1,000 women-years was 0.75 for tamoxifen versus 0.25 for placebo) have been reported. Cough as well as a case of exacerbation of asthma have also been reported.
Endocrine side effects have included elevations in T4 in the absence of clinical hyperthyroidism. This may be due to tamoxifen-induced elevations in circulating thyroid binding globulin. In addition, tamoxifen suppresses prolactin release in response to breast stimulation in puerperal women. Up to 30% of male breast cancer patients may experience a decrease in libido when treated with tamoxifen.
Psychiatric side effects including depression and delusional syndromes have been reported rarely.
Immunologic side effects have included a case report of purpuric vasculitis.
Rechallenge with tamoxifen resulted in reappearance of lesions.
Other side effects have included radiation recall and anorexia.
Tamoxifen-induced anorexia has been associated with fatty acid synthase inhibition in the ventromedial nucleus of the hypothalamus and accumulation of malonyl-CoA.
Dermatologic side effects including four cases of hair loss have been reported. One of those cases involved tamoxifen-induced total alopecia. A case of repigmentation following graying of the hair in a 68-year-old patient has also been reported.
One study has reported that when compared to healthy controls who were not using the drug, tamoxifen users exhibited significantly worse performance on visual memory, word fluency, immediate verbal memory, visuo-spatial ability, and processing speed tasks.
Nervous system side effects including adverse cognitive effects have been reported.
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