If you take heart or blood pressure medicines, do not stop them or avoid magnesium automatically—check with a healthcare professional before adding a supplement.
Medications that may interact with magnesium
1. Some blood pressure medicines
- Magnesium can sometimes add to the blood-pressure-lowering effect of certain medications, which may increase the chance of dizziness or low blood pressure in some people.
- People taking multiple blood pressure medicines should be especially careful.
2. Diuretics (“water pills”)
- Some diuretics affect magnesium levels in the body.
- Depending on the medication, magnesium levels may go up or down, so monitoring may be needed.
3. Calcium channel blockers
- Medicines used for blood pressure and heart conditions (such as some calcium channel blockers) may have effects that overlap with magnesium’s role in muscle and blood vessel function.
4. Heart rhythm medications
- People taking medicines for abnormal heart rhythms should discuss magnesium supplements with their clinician, especially if they have kidney problems or abnormal electrolyte levels.
Other important magnesium interactions
Magnesium can reduce absorption of several medications if taken too close together, including some:
- Antibiotics
- Thyroid hormone replacement medicines
- Osteoporosis medicines
A common precaution is to separate magnesium supplements from certain medications by a few hours, but the exact timing depends on the drug.
Who should be extra cautious?
Talk to a healthcare professional before taking magnesium supplements if you:
- Have kidney disease
- Take multiple heart or blood pressure medications
- Have a history of abnormal heart rhythms
- Are unsure whether your symptoms are from a deficiency
Magnesium from normal foods (such as nuts, seeds, beans, and leafy greens) is usually not a concern for most healthy people. The main interaction risks are more often associated with high-dose supplements.
