HYPOKALEMIA

Etiology Definition serum potassium concentration < 3.5 mEq/L total body potassium deficit Poor intake Excessive renal & GI loss serum potassium is shifted into the intracellular compartment drug

Drug induce hypo K

Category & Clinical presentation State Serum K level Clinical presenttation mild 3-3.5 mEq/L asymptomatic moderate 2.5-3 mEq/L cramping, weakness, malaise, and myalgias severe < 2.5 mEq/L ECG changes arrhythmias ECG changes: ST-segment depression or flattening,T-wave inversion, and U-wave elevation

Treatment K supplement  3 salt (Chloride, phosphate, carbonate) PO  mild to moderate (should be divided into 3-4 doses to minimize the developement of GI side effects) IV  severe (K < 2.5 mEq/L)  exhibiting signs symptoms of hypokalemia  patients unable to tolerate oral therapy

KCl oral 10% KCl elixir (20 mEq/15 ml) Ped KCl 2% (4 mEq/15ml) serum K 60 ml 0.3-0.8 120 ml 0.4-1.6 180 ml 0.6-2.4

KCl IV infusion NaCl D5W  advoided 10 to 20 mEq of potassium is diluted in 100 mL 0.9% NaCl administered through a peripheral vein over 1 hour Mutiple dose: can be repeated as needed until the serum potassium concentration normalizes (equilibium time 30 min)

KCl IV infusion (Conc.) Severe K depletion KCl 300 to 400 mEq/day dilute 40 to 60 mEq in 1,000 mL 0.45% NaCl Rate of infusion: not exceeding 40 mEq/h Central intravenous line into a large vein (e.g., superior vena cava)

Alternative therapy Potassium-sparing diuretics Spironolactone : 25-mg, 50-mg, and 100-mg tablets Start 25 to 50 mg daily  titrated to a maximum dose of 400 mg/day. side effects: hyperkalemia, gynecomastia, breast tenderness, and impotence

Alternative therapy Triamterene: 50-mg and 100-mg capsules Start 50 mg twice daily titrated to 100 mg twice daily side effects: hyperkalemia, sodium depletion, and metabolic acidosis Amiloride: 5-mg tablet Start 5 mg daily; however, 10 mg can be given in those with severe hypokalemia

Alternative therapy Generally, concomitant use of potassium supplementation with potassium-sparing diuretics is not necessary. There is a significant risk of hyperkalemia during combination therapy, especially in patients with underlying renal insufficiency or diabetes mellitus.

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