About letrozole
Aromatase inhibitor
Used for
- Treats hormone receptor-positive breast cancer after menopause.
- May reduce breast cancer recurrence after initial treatment.
- Sometimes used for fertility treatment outside approved labeling.
Usual adult dose
Breast cancer: 2.5 mg by mouth once daily. Fertility dosing varies by clinician.
Common side effects
- Hot flushes and sweating
- Joint or muscle pain
- Fatigue and dizziness
- Bone thinning and increased fracture risk
Important warnings
- Used mainly after menopause; it can harm an unborn baby.
- May reduce bone density; fracture risk can increase.
- Cholesterol may rise; monitoring may be needed.
- Report new or worsening bone pain or unusual symptoms.
Pregnancy
Avoid during pregnancy; it may cause fetal harm. Pregnancy status should be established before treatment when relevant.
Breastfeeding
Breastfeeding is not recommended during treatment and for at least 3 weeks after the last dose.
Interactions
- Tamoxifen can reduce letrozole levels and effectiveness.
- Estrogen-containing medicines may reduce its effectiveness.
- Rifampin may lower letrozole levels.
- Some medicines affecting liver enzymes, including certain seizure medicines, may alter its levels.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.