Quick answer

Ask your pharmacist or doctor before combining. Proton pump inhibitors can lower blood magnesium when taken for a long time, usually more than a year, according to NIH and the omeprazole label. The label calls the reports rare and says doctors may check magnesium before and during long-term use. Neither source explains how it happens.^1,2

Key facts

NIH says prescription proton pump inhibitors can cause low blood magnesium when taken for prolonged periods, typically more than a year.¹
The omeprazole label says low blood magnesium has been reported rarely after at least three months of treatment, in most cases after a year, and that doctors may check magnesium before and during long-term use.²
Serious events named on the label include tetany (muscle spasms), irregular heart rhythms and seizures.²
In the cases NIH describes from FDA's review, magnesium supplements did not raise magnesium in 25% of them and the patients had to stop the acid reducer.¹
MedlinePlus asks people to tell their doctor before taking omeprazole if they have ever had low magnesium.³

Your doctor may want to check on you

Proton pump inhibitors such as omeprazole and esomeprazole can cause low blood magnesium when taken for a long time, usually more than a year. The omeprazole label says this has been reported rarely after at least three months and that doctors may check magnesium before and during long-term use.^1,2,4

On the medicine's label

How long on a proton pump inhibitor before magnesium can drop?

MedlinePlus says omeprazole works by cutting the amount of acid the stomach makes. The omeprazole label says low blood magnesium has been reported rarely in people treated with proton pump inhibitors for at least three months, and in most cases after a year of treatment. NIH says it can happen when these medicines are taken for prolonged periods, typically more than a year.^1,2,3

The label calls the reports rare, and neither source explains how the medicine lowers magnesium. The label says doctors may consider checking magnesium before treatment starts, and from time to time, for people who expect a long course or who also take digoxin or medicines that can lower magnesium, such as water pills.²

Ask your pharmacist or doctor first

Long-term use of loop diuretics such as furosemide, and of thiazide diuretics such as hydrochlorothiazide, can increase the magnesium lost in urine, while potassium-sparing diuretics such as spironolactone reduce it. The furosemide label says it may lower blood magnesium and that levels should be checked periodically.^1,4,5

On the medicine's label

What are the signs of low magnesium?

NIH lists loss of appetite, nausea, vomiting, tiredness and weakness as early signs of low magnesium. As it worsens, numbness, tingling, muscle cramps and contractions, seizures and abnormal heart rhythms can occur. The omeprazole label names tetany (muscle spasms), irregular heart rhythms and seizures among the serious events reported, and says low magnesium may lead to low calcium or low potassium.^1,2

These signs have many causes, so tell your doctor about them instead of guessing. NIH also notes that the usual blood test has limits.¹

The usual blood test measures serum magnesium, which says little about how much magnesium the body holds overall, and no single test is considered satisfactory.¹

What happened when magnesium supplements were used in cases FDA reviewed?

NIH says that in the cases FDA reviewed, magnesium supplements often raised the low blood magnesium caused by these medicines. In 25% of the cases the supplements did not raise magnesium levels, and the patients had to stop the proton pump inhibitor. The omeprazole label says that in most patients, treating low magnesium required magnesium replacement and stopping the medicine.^1,2

These sources describe treating a low level that had already been found. They do not test whether taking magnesium in advance keeps levels from falling, and they do not rank forms of magnesium: NIH does not say which forms were used in those cases, so glycinate, L-threonate or any other form cannot be compared from them. Talk to your prescriber before stopping or changing either medicine or supplement.¹

Questions to ask about magnesium and your acid reducer

How long have I been on this acid reducer, and has anyone checked my magnesium?
Do I also take a water pill or digoxin, which the label says can matter for magnesium too?²
Which of my products contain magnesium, including antacids, laxatives and multivitamins?¹
Do any of the signs above apply to me?
Does my doctor want me to take magnesium, and in which form?

Bring the Supplement Facts panel of any magnesium product and the label of your acid reducer, so your pharmacist can see both.

Questions people ask

Can you take magnesium with proton pump inhibitors?

The sources checked describe the medicine lowering blood magnesium over time. They do not say whether to take a magnesium supplement, which depends on your own level, so ask your pharmacist or doctor.^1,2

Why do proton pump inhibitors cause low magnesium?

NIH and the omeprazole label say prolonged use can cause it, usually after a year or more, but neither explains the cause. The label calls the reports rare.^1,2

Do proton pump inhibitors deplete magnesium?

Long courses can lower blood magnesium in some people, according to NIH and the label. The label calls the reports rare and says doctors may check levels before and during long-term use.^1,2

Can I take magnesium glycinate or magnesium L-threonate with a proton pump inhibitor?

The sources do not compare forms for this question, and NIH does not say which forms were used in the cases it describes. Show your pharmacist the product you take.¹

How do proton pump inhibitors affect magnesium absorption and levels?

The sources describe lower blood magnesium after prolonged use. They do not describe a measured change in absorption, so the cause is not established there.^1,2

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Sources

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.