Hypokalemia medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Assistant Editor(s)-In-Chief: Jack Khouri
Overview
The most important step in severe hypokalemia is removing the cause, such as treating diarrhea or stopping offending medication.
- Patients treated with loop or thiazide diuretics can be offered medications that counteract their kaliuretic effect such as aldosterone antagonists (spironolactone and eplerenone) or distal sodium channel blockers (eg, amiloride).
- The combination of thiazide and loop diuretics should be avoided.
- Oral potassium administration is safer than the IV route.
- An oral dose should not exceed 20-40 mEq.
- IV potassium infusion should be reserved for symptomatic patients with severe hyperkalemia and patients who can't take oral supplements.
Mild hypokalemia
- Potassium levels in the range 3.0-3.5 mEq/L.
- Represent potassium deficit of 200-400 mEq.
- May be treated with oral potassium salt supplements: potassium chloride KCl (Sando-K®, Slow-K®) or potassium bicarbonate KHCO3 (which can be generated from the metabolism of many organic salts eg, potassium citrate, potassium gluconate, etc).
- Potassium-containing foods may be recommended, such as tomatoes, oranges or bananas, but they are less effective than oral supplements.
- Both dietary and pharmaceutical supplements are used for people taking diuretic medications (see Causes, above).
- KCl is the most effective replacement for metabolic alkalosis-associated hypokalemia.
- KHCO3 and the organic "alkalinizing" salts potassium citrate and potassium gluconate are recommended for hypokalemia associated with metabolic acidosis (chronic diarrhea, renal tubular acidosis,etc).
Severe hypokalemia
- Potassium levels below 3.0 mEq/L
- Potassium levels between 2.0 and 3.0 correspond to 400-800 mEq deficit.
- It may require intravenous supplementation. Typically, saline is used, with 20-40 mEq KCl per liter over 3-4 hours (ie, at an infusion rate of 10 mEq/L/h)
- Giving IV potassium at faster rates may predispose to ventricular tachycardias and requires intensive ECG monitoring.
- Giving IV KCl at doses >60 mEq/L are painful and can cause venous necrosis.
- Difficult or resistant cases of hypokalemia may be amenable to amiloride, a potassium-sparing diuretic, or spironolactone.
- When replacing potassium intravenously, infusion via central line is encouraged to avoid the frequent occurrence of a burning sensation at the site of a peripheral IV and the aforementioned venous necrosis. When peripheral infusions are necessary, the burning can be reduced by diluting the potassium in larger amounts of IV fluid, or mixing 3 ml of 1% lidocaine to each 10 meq of KCl per 50 ml of IV fluid. The practice of adding lidocaine, however, raises the likelihood of serious medical errors [3].
- Potassium infusions via a central line can reach 200 mEq/L (20 mEq in 100 mL of isotonic saline (see below)) but the administration rate should not be greater than 10–20 mEq per hour.
- Saline solutions are preferred to prevent potassium transcellular shifting that is triggered by dextrose-induced insulin release!