Prednisone is a widely prescribed corticosteroid drug. It reduces inflammation and can help relieve symptoms for many different conditions, including arthritis, asthma, severe allergies, multiple sclerosis, ulcerative colitis and even cancer.
If you've been prescribed prednisone and heard that the drug may lower your potassium levels, you may be concerned. Here's what you should know.
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Why Is Potassium Important?
Potassium is a mineral and electrolyte your body needs to maintain proper nerve and muscle function as well as a regular heartbeat. The National Institutes of Health suggests adult men get a minimum of 3,400 milligrams of potassium a day while women get 2,600 milligrams daily.
Read more: What Is the Recommended Daily Amount of Potassium?
Most healthy people should be able to get enough potassium by eating a balanced diet that includes potassium-rich foods like orange juice, potatoes, cantaloupe, lima beans, milk and dried apricots and other dried fruits, according to the University of Wisconsin Hospitals and Clinics Authority. There are potassium supplements, but consult your doctor before taking them as high potassium levels can be dangerous, per Harvard Health Publishing.
Prednisone and Low Potassium: Is There a Connection?
There have been occasional mentions in medical literature that prednisone may cause low potassium levels — a condition called hypokalemia — because it prompts your body to secrete potassium through urine. But the research so far is very limited.
"There's not much evidence on this particular question," says Gerald Hladik, MD, chief of the division of nephrology and hypertension at the University of North Carolina School of Medicine in Chapel Hill. "One 1975 study of lung-transplant patients found that high doses of prednisone may slightly increase urinary potassium excretion. But in general, it's not clinically significant."
The study appeared in the British Journal of Diseases of the Chest and involved only eight patients, all of whom had lung disease. The authors noted that patients excreted more potassium in their urine at higher doses of prednisone, whether or not they were also taking potassium supplements. The participants didn't have any problems with blood potassium levels or actual health outcomes. There has been little, if any, research since then.
However, prednisone and other steroid medications may interact with different drugs to affect potassium levels.
For example, corticosteroids are more likely to contribute to hypokalemia if prescribed with certain diuretics like acetazolamide, according to the Prescribers' Digital Reference.
When combined with prednisone, some antibiotics, including penicillin, as well as beta-2 receptor agonists like Albuterol (used to treat asthma), may lower potassium levels, according to a March 2015 paper in Pharmacy & Therapeutics.
Always tell your doctor about any medications you’re taking and any health conditions you're experiencing so he or she can determine the effect prednisone may have on you.
If you're concerned about your potassium levels, check with your doctor, who can take a blood sample and send it to the lab for testing. This is the only way to know for sure what your potassium levels are.
Mild hypokalemia often has no symptoms, according to the Cleveland Clinic, although severe hypokalemia may cause muscle weakness or cramps, an irregular heartbeat, thirst and confusion.
Read more: Foods That Cause High Potassium Levels
Other Prednisone Side Effects to Note
Prednisone does have other side effects, some of which can be serious enough that your doctor may not want you to take the medication for long periods of time.
Many people on the drug gain weight, because prednisone makes you retain fluid and can also make you really hungry. Prednisone can also deplete other nutrients, like calcium and vitamins C and D, according to National Jewish Health. And some people get sick more frequently because prednisone suppresses your immune system.
Taking steroids long-term can cause cataracts, osteoporosis and even diabetes, notes the Mayo Clinic.
- Mayo Clinic: “Prednisone (Oral Route).”
- National Institutes of Health: “Potassium.”
- British Journal of Diseases of the Chest: “Potassium supplements in patients treated with corticosteroids.”
- Kaiser Permanente: “Prednisone.”
- Memorial Sloan Kettering Cancer Center: “Prednisone.”
- American College of Cardiology: "Prednisone"
- National Jewish Health: “Steroids and Nutrition.”
- University of California San Francisco: “ILD Nutrition Manual: Prednisone and Weight Gain.”
- Prescribers’ Digital Reference: “prednisone - Drug Summary.”
- National Library of Medicine: “Prednisone.”
- Pharmacy & Therapeutics: “Medication-Induced Hypokalemia.”
- Cancer Medicine: “Physiologic and Pharmacologic Effects of Corticosteroids.”
- Mayo Clinic: “Prednisone and other corticosteroids."
- University of Wisconsin Hospitals and Clinics Authority: "Health Facts For You."
- Cleveland Clinic: " Low Potassium Levels in Your Blood (Hypokalemia)."
- Harvard Medical School: "Should I take a potassium supplement?"
Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.