- Hot flashes
- Mood swings
- Vaginal problems (e.g. dryness, discharge)
- Erectile dysfunction
- Decreased sexual desire (both sexes)
- Fatigue and reduced energy
- Nausea and vomiting
- Weight gain
- Loss of bone mass and strength (osteoporosis)
- Thinning of hair and nails
- Mild anemia
- Liver problems
In addition, women who take tamoxifen may be at higher risk for endometriosis, endometrial cancer and fertility problems. They may also develop thrombosis (blood clots) and have a slightly higher risk of suffering a stroke.
In some cases, patients who take hormone therapy drugs over a long period of time may find that their cancers develop resistance to the medication. For this reason, some drugs may be given for a period of time, discontinued, and started again at a later date. This schedule is used in the hope of preventing the development of such resistance. If resistance occurs, the patient may be switched to a new hormone therapy medication.
Recent research has indicated that changing drug treatments for women with breast cancer may reduce the risk of recurrence of the disease. In clinical trials, postmenopausal women who switched from five years of an anti-estrogen drug to an aromatase inhibitor demonstrated a lower risk of recurrent breast cancer. Other research has suggested that switching during the five-year standard treatment with tamoxifen may benefit certain breast cancer patients as well. Additional research is needed to confirm the findings of these studies.
