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. The oral route for potassium repletion (40 mEq KCL, PO, Q 4-6 hours) is the safest. Severe hypokalemia can be treated via IV KCl infusion (10 mEq/hour KCL) with doses that shouldn't exceed 60 mEq/L unless ECG monitoring is provided. A central line can be used for administration of greater concentrations of KCl.[1]
Medical Therapy
The most important step in severe hypokalemia is removing the cause, such as treating diarrhea or stopping offending medication. If hydration is needed, dextrose solutions should be avoided because dextrose increases insulin which can causes intracellular shift of potassium, and further exacerbates hypokalemia.
- 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.
- IV potassium infusion should be reserved for symptomatic patients with severe hyperkalemia and patients who can't take oral supplements.
Dosages for potassium repletion are:
- PO: 40 mEq KCL Q 4-6 hours
- IV: 10 mEq/hour KCL
Notes the following:
- Check the potassium concentration frequently.
- Avoid excessive potassium repletion, particularly in the cases of transcellual shifts of potassium that can be reversed when the initial cause of hypokalemia is treated.
- Treat low magnesium blood concentration.
There are many oral potassium salts that can be prescribed including potassium chloride KCl (the most popular) and the organic alkalinizing salts that are metabolized to potassium bicarbonate KHCO3 in the body.
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.
- 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.[2]
- Potassium infusions via a central line can reach 200 mEq/L (20 mEq in 100 mL of isotonic saline) 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.
Contraindicated medications
Hypokalemia is considered an absolute contraindication to the use of the following medications:
References
- ↑ Chang SL, Hsiao YW, Tsai YN, Lin SF, Liu SH, Lin YJ; et al. (2018). "Interleukin-17 enhances cardiac ventricular remodeling via activating MAPK pathway in ischemic heart failure". J Mol Cell Cardiol. doi:10.1016/j.yjmcc.2018.08.005. PMID 30096409.
- ↑ "Safety Issues With Adding Lidocaine to IV Potassium Infustions (Excerpt)". Retrieved 2013-02-27.