Tamoxifen blocks the actions of estrogen, and is used to treat certain types of breast cancer. Some types of breast cancer require estrogen to spread. Some women are prescribed Tamoxifen if they have a high risk of developing breast cancer, such as a family history of the disease. This drug is manufactured by AstraZeneca and was approved in 1989.
In a study conducted in Sweden, researchers compared two groups of 1,372 women. The first group took the drug Tamoxifen, while the second group was the control group. 23 of the patients in the first group contracted uterine cancer, while only four patients in the second group developed the disease. This study pointed to the fact that Tamoxifen increases the risk of uterine cancer in women and the FDA now warns patients of these risks.
Another study found that women who take this drug for more than a year may suffer from memory loss and decreased cognitive abilities. In the test, women took a verbal memory and executive function test. The women who had taken Tamoxifen for an extended period of time scored lower, according to researchers in Amsterdam.
This drug has also been thought to cause pulmonary embolisms and may even increase the risk of relapse in cancer patients.
Serious side effects may include:
- Sudden numbness or weakness, especially on one side of the body
- Sudden severe headache, confusion, problems with vision, speech, or balance
- Chest pain, sudden cough, wheezing, rapid breathing, fast heart rate
- Pain, swelling, warmth, or redness in one or both legs
- Nausea, loss of appetite, increased thirst, muscle weakness, confusion, and feeling tired or restless
- Unusual vaginal bleeding or discharge
- Irregular menstrual periods
- Pain or pressure in your pelvic area
- Blurred vision, eye pain, or seeing halos around lights
- Easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin
- Fever, chills, body aches, flu symptoms
- New breast lumps
- Upper stomach pain, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes)
Less serious side effects may include:
- Hot flashes
- Bone pain, joint pain, or tumor pain
- Swelling in your hands or feet
- Vaginal itching or dryness
- Decreased sex drive, impotence, or difficulty having an orgasm
- Headache, dizziness, depression
- Thinning hair