High blood levels of the electrolyte potassium, a condition known as hyperkalemia, can cause serious problems with your heart. Diuretics, drugs that increase urine output in people with high blood pressure or other health problems, can cause hyperkalemia, defined as serum levels greater than 5.3 milliequivalents per liter, or mEq/L. People taking diuretics need blood tests on a regular basis to assess for hyperkalemia.
Cause
Not all diuretics cause hyperkalemia. Normally diuretics wash out not only excess fluid in your body but also electrolytes such as potassium, resulting in lower potassium levels, or hypokalemia. A class of diuretics known as potassium-sparing diuretics, which includes the drugs amiloride, spironolactone and triamterene, conserve potassium rather than eliminate it to decrease the incidence of hypokalemia. Only potassium-sparing diuretics increase the risk of developing hyperkalemia.
Frequency
Potassium-sparing diuretics commonly cause mild hyperkalemia, The Merck Manuals Online Medical Library reports. Between 4 to 19 percent of people taking potassium-sparing diuretics developed moderate to severe hyperkalemia in some studies, reports Mark Perazella, M.D., of the Nephrology Department at the Yale University School of Medicine, in the Sept. 2000 issue of "The American Journal of Medicine." As many as 26 percent of patients taking Dyazide, a commonly used combination of triamterine and hydrochlorothiazide, developed hyperkalemia in other studies, Dr. Perazella added.
Risk Factors
People who have underlying kidney disease, those with diabetes and people undergoing hemodialysis treatment have an increased likelihood of developing hyperkalemia if they take potassium-sparing diuretics, Dr. Perazella states.
Symptoms
Mild hyperkalemia often has no symptoms, but hyperkalemia can cause an irregular heart rate, nausea, vomiting or a slow, weak pulse. Sudden cardiac arrest can occur without warning in people with hyperkalemia, MedlinePlus warns.
Diagnosis and Treatment
Blood tests can diagnose hyperkalemia. An electrocardiogram, or EKG, can show irregularities in the heart rate such as abnormal rhythms or a heart block, with a slower than normal heartbeat. Stopping the drugs causing hyperkalemia is often enough to cure the problem. Loop diuretics, which eliminate potassium along with excess fluid, may be given.
