Electrolyte Guide



Replete if ionized Calcium < 1.0

  • Calcium gluconate: 1g Calcium gluconate IV over 1 hour
  • Calcium chloride: 13.6 mEq of elemental calcium; DO NOT give peripherally, risk of thrombophlebitis


Goal > 2.0

Level IV
<1.0 Magnesium Sulfate 1g x 4 doses @ 1g/hr
1.0-1.4 Magnesium Sulfate 1g x 3 doses @ 1g/hr
1.5-2.0 Magnesium Sulfate 1g x 2 doses @ 1g/hr


Oral: Phospha 250 neutral (Neutra-phos)

IV: Potassium/Sodium Phosphate 15mmol

Level Oral IV
<1.5 0.5mmol/kg sodium phos
1.5-2.0 Neutraphos 0.25mmol/kg 0.25mmol/kg sodium phos
2.1-2.4 0.15mmol/kg sodium phos


Normal Range: 3.6-5.0 mEq/L


Goal: in general >3.5, in cardiac patients >4.0; use caution when repleting in patients with renal dysfunction

  • Always replete magnesium first if Mg++<2.0mg/dl

  • Note: when repleting via IV: 10mEq/hr via peripheral line or 20meq/hr central line

  • Every 10 mEq of K given is expected to raise the K by 0.1 (i.e. if you give 40mEq of K to a patient with K of 3.4, expect the repeat K to be approximately 3.8)

If rechecking, do so 3 hours after dose

Level Oral IV
<3.3 Kdur 60mEq KCl 60mEq
3.3-3.5 Kdur 40mEq KCl 20mEq
3.6-4.0 Kdur 20mEq KCl 20mEq


  • check if sample was hemolyzed or sent off IV running potassium; if either is true, order stat plasma K and recheck

  • if renal failure: patient may require immediate medical management and urgent dialysis

Hyperkalemic emergency:

  • clinical manifestations of hyperkalemia (muscle weakness, paralysis, cardiac conduction abnormalities or arrhythmias)

  • serum K > 6.5 meq/L

  • serum K > 5.5 meq/L with significant renal impairment and ongoing tissue breakdown (rhabdo, TLS, etc.)

treat with rapidly acting therapies (calcium gluconate 1g IV, insulin IV + D50) and removal (dialysis, GI cation exchangers if no contraindication, diuretics)