Heartburn Medicine or Water Pill? It May Be Worth Checking Your Magnesium

Many adults over 60 take the same medications every day for years, and the list often goes unchecked for a long time. Two of the most common are medicines for heartburn and for blood pressure or swelling, often known as water pills. Certain versions of both can lower magnesium levels, especially with long-term use, and magnesium is often not included in routine blood tests.

Heartburn Medicines

The heartburn drugs are proton pump inhibitors, or PPIs. They include omeprazole (Prilosec), esomeprazole (Nexium), lansoprazole (Prevacid) and pantoprazole (Protonix). These medicines reduce stomach acid and are effective for reflux and ulcers.

The NIH Office of Dietary Supplements, part of the National Institutes of Health, says prescription PPIs can lead to low magnesium when used for long periods, usually more than a year. It also summarizes what the U.S. Food and Drug Administration found when reviewing such cases. Magnesium supplements often brought the level back up, but in about a quarter of the reports they did not, and the patient had to stop the PPI. That comes from the cases the FDA reviewed, so it does not predict an individual person’s risk. The FDA advises doctors to consider checking magnesium before starting long-term PPI treatment and to monitor it periodically afterward.

The NIH guidance applies to prescription PPIs. If you use an over-the-counter version every day, let your doctor know how long you have been taking it.

Water Pills

Some diuretics, which increase urination, can also cause the body to lose more magnesium over time. The NIH names two types: loop diuretics such as furosemide (Lasix) and thiazide diuretics such as hydrochlorothiazide. A third type, potassium-sparing diuretics such as spironolactone (Aldactone), has the opposite effect and helps reduce magnesium loss.

Why Age Raises the Risk

The NIH identifies older adults as a group at higher risk for low magnesium. With age, people often consume less magnesium, absorb less of it in the intestines, and pass more of it into the urine through the kidneys. They are also more likely to have chronic illnesses or take medications that affect magnesium levels.

In otherwise healthy people, the NIH says, a low-magnesium diet alone rarely causes symptoms because the kidneys conserve magnesium when intake is low. Deficiency is more likely to result from long-term low intake, certain medical conditions, heavy alcohol use or specific medicines.

Why a Blood Test May Miss It

My book, Your Labs Are Fine. You’re Not, focuses on the gap between a normal lab result and how someone feels. Magnesium is one of the clearest examples.

Less than 1% of the body’s magnesium is in the blood. Most of it is stored in bones and soft tissues. The NIH says the body tightly controls blood levels, and those levels have little connection to the body’s overall magnesium stores. It also notes that magnesium is not part of routine electrolyte testing in hospitals and clinics. So a standard chemistry panel at a checkup may not include magnesium at all. Even when it does, a normal number does not necessarily mean the body’s stores are adequate.

The blood test still has value. The NIH calls it the most commonly used and easiest way to assess magnesium, and it is the test the FDA advises doctors to consider for people on long-term PPIs. A low result is something a doctor can address. The NIH also says no single test is fully satisfactory, so a doctor may consider symptoms and medical history along with the number.

What Low Magnesium Can Feel Like

The NIH lists loss of appetite, nausea, vomiting, fatigue and weakness as early signs. As deficiency worsens, symptoms can include numbness, tingling, muscle cramps, seizures, personality changes and an abnormal heart rhythm. These symptoms can have many causes. A doctor can review your medications, examine you and decide whether a magnesium test or other evaluation is needed. A seizure, or a fast or irregular heartbeat, requires immediate medical attention.

What to Do

Do not stop a prescribed PPI or water pill until you have spoken with your doctor. The NIH advises people who use these medicines regularly to discuss their magnesium intake with a health care provider. Then:

• Write down every medicine you take, including over-the-counter heartburn pills, and how long you have used each one.
• Bring the list to your doctor or pharmacist and ask, “Do any of these lower my magnesium? Has my magnesium been checked, and should it be?”
• Ask before starting a magnesium supplement. This is especially important if you have kidney disease, because poorly functioning kidneys cannot clear extra magnesium well.
• Eat magnesium-rich foods. According to the NIH, 1 ounce of roasted pumpkin seeds has about 156 mg, 1 ounce of dry-roasted almonds 80 mg, half a cup of boiled spinach 78 mg, and half a cup of cooked black beans 60 mg. The recommended daily amount for women over 50 is 320 mg.

In my book, I use a method I call Feel. Pause. Act. With magnesium, you may feel tiredness or cramps. Before assuming it is just age or buying a supplement, pause and look at what you already take. Then act by bringing that list to someone who can check it.

A normal lab report tells you what tests were run. It is fair to ask which ones they were.