POTASSIUM SUPPLEMENTATION

Who Needs Nondietary Potassium Supplementation?

Very few people actually need to take a potassium supplement or a potassium-sparing diuretic (amiloride, spironolactone, triamterene). If, however, you take digoxin, have severe liver disease, or take large doses of diuretics (water pills) for heart disease, eating a potassium-rich diet may not be sufficient to replace the potassium that you are losing. If you fall into one of these categories, it is very important for your doctor to precisely monitor and regulate the amount of potassium in your bloodstream. A potassium supplement or a potassium-sparing diuretic may be necessary. Read about the methods of increasing the potassium in your body discussed below and consult with your doctor about which will be best for you.

Who Does Not Need It?

Most people taking a thiazide diuretic (hydrochlorothiazide or metolazone, for example) for high blood pressure (hypertension) do not need potassium-sparing diuretics[1] or potassium supplements. This is especially true if treatment is started at a low dose (12.5 milligrams of hydrochlorothiazide for treatment of mild hypertension). Supplementing the diet with potassium-rich foods or beverages (see tables below) is sufficient to prevent low levels of potassium.[2]

Mild potassium deficiency (between 3.0 and 3.5 millimoles of potassium per liter of blood) can occur during diuretic therapy, but it usually has no symptoms and requires no treatment other than eating foods that are rich in potassium. Most people do not get severe potassium deficiency (less than 3.0 millimoles per liter) from treatment with diuretics. Comparisons of people eating a potassium-rich diet, people taking potassium supplements, and people taking potassium-sparing drugs have shown that (1) diet is the safest method of replacing potassium and (2) potassium supplements and potassium-sparing drugs return potassium levels to normal in only 50% of the users. Therefore, if you have mild potassium deficiency, eat a few bananas before risking the adverse effects of potassium supplements or potassium-sparing drugs. Ask your doctor what your potassium levels were before and after you started diuretic treatment. You probably do not need a nondietary potassium supplement or potassium-sparing drug.

Three Ways to Increase Your Potassium Levels

The safest and least expensive way is to increase the amount of potassium-rich food in your daily diet. This will provide sufficient potassium replacement for the overwhelming majority of people taking diuretics (people who also take digoxin or who have liver disease may be exceptions).

Restricting sodium (salt) intake also helps to maintain potassium levels while lowering sodium levels. In fact, salt substitutes containing potassium chloride may be an additional source of potassium intake.[2] If you are already taking potassium supplements or potassium-sparing diuretics, consult your doctor before using salt substitutes. A dosage adjustment may be necessary to prevent too much potassium in the body, a potentially fatal condition.

Potassium supplements are a second method for replacing potassium, but these can cause serious adverse reactions. Potassium is an irritant to the mucous membranes that line the mouth, throat, stomach, and intestines. If not properly dissolved and dispersed in the digestive tract, potassium can come in contact with these membranes and cause bleeding, ulcers, and perforations. Use of potassium supplements, because of serious potential adverse effects, should be restricted to people who are eating plenty of potassium-rich foods, yet still have a low level of potassium in their blood (less than 3.0 millimoles per liter).[3]

There are several kinds of potassium supplements:

• Liquids: Liquid supplements are safer than tablets[1] because, when taken in a diluted form over a five- to ten-minute period, potassium is effectively dispersed in the digestive tract, and thus causes less stomach and intestinal irritation and ulceration. Packaged as a liquid, powder, or dissolvable tablet, all forms must be completely dissolved in at least one-half cup of cold water or juice before drinking, and then sipped slowly over five to ten minutes.
• Extended-release tablets or capsules: Although liquid supplements are safest, tablets and capsules are widely used to avoid the unpleasant taste of the liquids.[1] Rarely, but often unpredictably, these tablets and capsules can cause stomach and intestinal ulcers, bleeding, blockage, and perforation when the potassium in the tablets and capsules does not dissolve and comes in contact with the lining of the digestive tract. Abdominal pain, diarrhea, nausea, vomiting, and heartburn have also been reported. Because the amount of time required for food to be digested and travel through the digestive tract increases with age, older people are more likely to experience adverse effects with these tablets or capsules.[1] Increased transit time leaves more opportunity for an undissolved or partially dissolved tablet or capsule to damage mucous lining.
• Enteric-coated tablets: Avoid these. “Enteric-coated” potassium tablets are not reliably absorbed and have frequently been blamed for intestinal ulceration.[4]

The last method for increasing potassium levels is with a of drugs called potassium-sparing diuretics. Examples of these drugs are spironolactone (ALDACTONE), triamterene (DYRENIUM), and amiloride (MIDAMOR). Potassium-sparing diuretics are also found in combination products such as Moduretic and Aldactazide. These should not be used for older adults. These drugs can cause potentially fatal adverse effects such as kidney failure and the retention of too much potassium, which causes irregular heartbeats and heart rhythm. Studies have shown that the potassium supplements discussed above are equally effective and less dangerous than potassium-sparing diuretics, if nondietary potassium replacement is required.

If you are taking a potassium-sparing diuretic, you should never also use a potassium supplement or salt substitute containing potassium.[1] You also should not use an ACE inhibitor such as captopril (CAPOTEN) with potassium supplements because of the risk of high levels of potassium. Too-high levels of potassium, a potentially fatal condition that may not produce warning symptoms, may develop rapidly.