Taking a Heartburn Pill or a Water Pill? Ask About Your Magnesium

Many of us over 60 take the same pills every morning for years, and it has been a while since anyone reviewed the list. Two of the most common are a pill for heartburn and a pill for blood pressure or swelling, often called a water pill. Certain kinds of both can lower your magnesium, particularly with long-term use, and magnesium is often left off routine blood work.

Heartburn Pills

The heartburn pills are called proton pump inhibitors, or PPIs. They include omeprazole (Prilosec), esomeprazole (Nexium), lansoprazole (Prevacid) and pantoprazole (Protonix). They reduce stomach acid, and they work well for reflux and ulcers.

The NIH Office of Dietary Supplements, part of the National Institutes of Health, says prescription PPIs can cause low magnesium when taken for long periods, typically more than a year. It also reports what the U.S. Food and Drug Administration found when it reviewed these cases. Magnesium supplements often raised the low levels. In a quarter of the cases they did not, and the patient had to stop the PPI. That figure comes from the reported cases the FDA reviewed, so it does not tell you your own chances. The FDA advises doctors to consider checking magnesium before starting long-term PPI treatment and to check it periodically after that.

The NIH statement covers prescription PPIs. If you take an over-the-counter version every day, tell your doctor how long you have been taking it.

Water Pills

Some diuretics, the pills that make you pass more urine, also make you lose more magnesium in your urine when you take them for a long time. The NIH names two kinds: loop diuretics such as furosemide (Lasix) and thiazide diuretics such as hydrochlorothiazide. A third group, the potassium-sparing diuretics such as spironolactone (Aldactone), has the opposite effect and reduces magnesium loss.

Why Age Matters

The NIH lists older adults as a group at risk of low magnesium. As we age, we tend to eat less magnesium, our gut absorbs less of it, and our kidneys pass more of it into urine. We are also more likely to have chronic illnesses or to take medicines that change magnesium levels.

In otherwise healthy people, the NIH says, a low-magnesium diet alone seldom causes symptoms, because the kidneys hold on to magnesium when intake is low. What can lead to a deficiency is low intake over a long time, certain health conditions, heavy drinking or certain medicines.

Why Your Blood Work May Not Show It

My book, Your  Labs Are Fine. You’re Not, is about the gap between a normal lab result and how you feel. Magnesium is one of the clearest examples.

Less than one percent of the magnesium in your body is in your blood. Most of it is in your bones and soft tissues. The NIH says the body keeps the blood level under tight control, and that blood levels have little correlation with how much magnesium your body holds overall. It also says magnesium is not evaluated during routine electrolyte testing in hospitals and clinics. So the basic chemistry panel at your checkup may not include magnesium at all. If it does, a normal number does not prove your stores are full.

The blood test is still worth having. The NIH calls it the most commonly used and readily available way to assess magnesium, and it is the test the FDA advises doctors to consider for patients on long-term PPIs. A low result is a finding your doctor can act on. The NIH also says no single test is considered satisfactory, so your doctor may weigh your symptoms and 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 the deficiency worsens, signs can include numbness, tingling, muscle cramps, seizures, personality changes and an abnormal heart rhythm. These symptoms have many possible causes. Your doctor can review your medicines, examine you and decide whether a magnesium test or other checks are needed. A seizure, or a racing or irregular heartbeat, needs medical care right away.

What to Do

Keep taking a prescribed PPI or water pill until you have talked with your doctor. The NIH advises people who take these medicines regularly to discuss their magnesium intake with their health care providers. Then:

• Write down every medicine you take, including over-the-counter heartburn pills, and how long you have taken each one.
• Take 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 you start a magnesium supplement. This matters most if you have kidney disease, because kidneys that work poorly cannot clear extra magnesium well.
• Eat magnesium-rich foods. According to the NIH, an ounce of roasted pumpkin seeds has about 156 mg, an 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 the book I use a method I call Feel. Pause. Act. With magnesium, you feel the tiredness or the cramps. Before deciding it is age, or buying a supplement, you pause and look at what you already take. Then you act: you bring that list to someone who can check it.

A normal lab report tells you about the tests that were run. It is fair to ask which tests those were.

Please Join the Conversation:

Which of the above symptoms do you recognize? Has anyone ever checked your magnesium, or talked with you about how your daily medicines affect it?