Can I take Letrozole and Magnesium together?

Why this happens

Letrozole is processed by the liver (specifically the CYP3A4 and CYP2A6 enzymes), while magnesium is a mineral absorbed in the intestines and excreted by the kidneys. They do not interfere with each other's absorption or metabolism.

You can continue taking both as prescribed. However, letrozole can sometimes cause joint pain or bone thinning; magnesium is often used to support bone health, but you should always inform your doctor or pharmacist about all supplements you are taking to ensure your overall treatment plan is balanced.

Pregnancy and Breastfeeding

You must not take letrozole if you are pregnant or breastfeeding as it can cause severe harm to a developing baby. If you are pre-menopausal, you must use effective contraception during treatment and for at least 20 days after stopping.

Severe Kidney Disease

Do not take magnesium supplements if you have severe kidney impairment. Your kidneys may not be able to remove excess magnesium from your blood, which can lead to dangerous levels (hypermagnesaemia) affecting your heart and breathing.

Osteoporosis (Bone Thinning)

Letrozole significantly lowers oestrogen levels, which can lead to rapid bone mineral loss and increased risk of fractures. Your doctor should monitor your bone density before and during treatment.

Alcohol

Chronic or excessive alcohol consumption can increase the amount of magnesium your body loses through urine, potentially making the supplement less effective.

Large meals / High-fat foods

Taking magnesium on an empty stomach can sometimes cause diarrhoea or stomach upset. Taking it with a small meal or snack can help prevent this.

Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.

Disclaimer

This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.