If you’re looking for the details behind this headline, the word “NEVER” is too strong. Magnesium supplements can interact with certain medicines, but in many cases the solution is simply to separate the doses by several hours, not avoid magnesium completely. The risk also depends on the dose, kidney function, and the specific medication. (Office of Dietary Supplements)
Medications that deserve particular attention
- Certain antibiotics
Magnesium can bind to tetracycline antibiotics such as doxycycline and quinolone antibiotics such as ciprofloxacin and levofloxacin, reducing their absorption. NIH guidance recommends taking these antibiotics at different times from magnesium. (Office of Dietary Supplements) - Bisphosphonates for osteoporosis
Magnesium can reduce absorption of oral medicines such as alendronate. These medicines should be separated from magnesium according to the medication instructions. (Office of Dietary Supplements) - Some diuretics (“water pills”)
Loop and thiazide diuretics can increase magnesium loss through urine, while potassium-sparing diuretics can have the opposite effect. This is something a clinician may monitor rather than a reason to automatically avoid magnesium. (Office of Dietary Supplements) - Proton-pump inhibitors (PPIs)
Long-term use of medicines such as omeprazole or esomeprazole can lower magnesium levels. In some people, supplementation may actually be needed if a deficiency develops. (Office of Dietary Supplements) - Some medicines taken with mineral supplements
Magnesium can interfere with absorption of certain medicines, so pharmacists may recommend a specific time interval between them.
An important warning about high doses
For adults, the NIH lists 350 mg per day as the upper limit for magnesium from supplements and medications, unless a healthcare professional recommends otherwise. This limit does not apply to magnesium naturally present in food. Excess supplemental magnesium can cause diarrhea and abdominal cramping, while extremely high amounts can cause low blood pressure, irregular heartbeat and potentially life-threatening toxicity. (Office of Dietary Supplements)
People with impaired kidney function need particular caution because the kidneys normally remove excess magnesium.
Bottom line: Don’t automatically stop magnesium because you’re taking medication. Instead, have a pharmacist or doctor check your exact medicines, magnesium dose and kidney function. And don’t change a prescribed medication without medical advice.
