American Board of Internal Medicine (ABIM) Certification Practice Exam

What is a common toxicity of tamoxifen?

1. Weight gain

2. Hot flushes

3. Fatigue

4. Nausea

The correct answer is: Hot flushes

Tamoxifen, a selective estrogen receptor modulator (SERM) commonly used in the treatment and prevention of breast cancer, has a range of side effects due to its action on estrogen receptors in various tissues. One of the most frequently reported toxicities associated with tamoxifen is hot flushes. Hot flushes result from tamoxifen's antagonistic effect on estrogen receptors in the hypothalamus, which regulates body temperature. This leads to the classic symptom of sudden feelings of warmth, sweating, and reddening of the skin, particularly affecting the upper body. While other side effects such as weight gain, fatigue, and nausea may occur, hot flushes stand out as a particularly common experience for patients undergoing treatment with tamoxifen. Additionally, the prevalence of hot flushes with tamoxifen treatment has been substantiated in clinical studies, making them a well-recognized side effect. Understanding these toxicities is important for patient management and counseling.