Medically reviewed by Patricia Mikula, PharmDMedically reviewed by Patricia Mikula, PharmD.

Magnesium is an essential mineral crucial for many bodily functions. It is necessary for more than 300 biochemical reactions in the body, including blood sugar control, blood pressure regulation, and muscle and nerve function. Magnesium also supports bone health and is important for immune health and normal heart rhythm.

Magnesium is naturally found in many foods and is also available as a nutritional supplement. Good dietary sources of magnesium include nuts, seeds, legumes, whole grains, fruits such as bananas and avocados, and dark, leafy greens such as spinach. Magnesium is also added as a nutrient to cereals and other fortified foods.

While magnesium is available as a supplement, it is not recommended unless you are magnesium deficient. There are some medications you shouldn't mix with magnesium to avoid potential side effects or interactions.

Antibiotics

Magnesium can interact with certain antibiotics, including tetracyclines such as Declomycin (demeclocycline), Vibramycin (doxycycline), and quinolone antibiotics such as Cipro (ciprofloxacin) and Levaquin (levofloxacin).

Antibiotics taken with magnesium or taken too soon after magnesium may not be absorbed properly or work as effectively. To ensure optimal absorption, take your antibiotics at least two hours before or 4-6 hours after your magnesium supplement. This timing varies based on the kind of antibiotic you're taking.

Diuretics

Diuretics are drugs that help the body get rid of excess salt and fluid by causing the kidneys to produce more urine. Taking diuretics alongside magnesium can either increase or decrease the loss of magnesium through the passage of urine, depending on the type of diuretic taken.

Taking diuretics with magnesium will also counteract the effects of magnesium since they cause hypomagnesemia, a condition in which magnesium levels become dangerously low in the blood. Low levels of magnesium can cause symptoms such as muscle weakness, hyperexcitability, and sleepiness.

Bisphosphonates

Magnesium-rich supplements can decrease the absorption of oral bisphosphonates, a family of drugs used to treat osteoporosis, a chronic (long-lasting) health condition that causes bones to become weak and brittle.

This interaction can occur when bisphosphonates, such as Fosamax (alendronate) are taken too soon before or after magnesium. To prevent this, take bisphosphonates at least two hours before or after magnesium supplementation. This timing depends on which bisphosphonate you're using. For some, the guidance is to wait 30-60 minutes.

Proton Pump Inhibitor (PPI) Drugs

When taken for prolonged periods of time (more than one year), proton pump inhibitor (PPI) drugs that treat peptic ulcers and relieve symptoms of acid reflux can cause low blood magnesium levels. Peptic ulcers are open sores on the inside of the stomach, while acid reflux is a condition that occurs when stomach acid moves up into the esophagus, causing a burning sensation known as heartburn.

PPI drugs include Nexium (esomeprazole) and Prevacid (lansoprazole). If you are taking PPIs or have been prescribed them, see a healthcare provider to get your blood levels of magnesium tested before starting long-term PPI treatment, and consider getting your magnesium blood levels tested periodically while on the medication.

Zinc

Zinc is an essential trace mineral that is necessary in small amounts to support health. It is an important mineral for wound healing, immune function, blood clotting, and other bodily functions.

Research has found that taking very high doses of zinc alongside magnesium can affect the body's ability to absorb and regulate magnesium. To avoid this potential interaction, take zinc and magnesium separately and at different times of the day.

When To See A Healthcare Provider

If you take any of the above medications, speak with your healthcare provider about whether it's safe to take your medications with supplemental magnesium. In some cases, magnesium can still be taken if administered at a different time than your medication.

You should also visit your healthcare provider if you experience any side effects from magnesium, which may include skin flushing, abdominal pain, impaired reflexes, diarrhea, nausea, or vomiting. Other side effects may include electrolyte disorders such as hypocalcemia and hyperkalemia.

Here are two calcium-related conditions to be aware of:

Other serious side effects of magnesium include breathing difficulty, heart failure, and hypothermia (when the body's core temperature drops below 95 degrees Fahrenheit). While side effects are rare if magnesium is taken in the correct dosage and form, they can still occur. If you experience serious side effects, visit your nearest emergency room or call 911.

A Quick Review

Magnesium is an essential mineral that supports more than 300 biochemical reactions in the body, including muscle and nerve function, heart rhythm, blood sugar control, blood pressure regulation, and more. Magnesium is found naturally in many foods, including nuts, seeds, legumes, whole grains, fruits, and vegetables, and is also available as a dietary supplement.

Certain medications should not be taken with magnesium, including certain antibiotics, PPI drugs, diuretics, bisphosphonates, and high doses of zinc. If you take any of these medications and might need to supplement your diet with magnesium, speak to your healthcare provider before adding any new medications or supplements to your daily routine.