Potassium Chloride

KCl · K-Dur · Klor-Con

Potassium salt for replacement therapy

Provides K⁺ for replacement of intracellular and serum stores. Maintains resting membrane potential. 1 mEq KCl = 39 mg potassium.

Indications

Context	Adult	Pediatric
Acute IV severe (K <3.0)	10–20 mEq/h IV via central line, with continuous ECG; max 40 mEq/h via central with strong indication	—
Acute IV peripheral	10 mEq/h max, concentration ≤10 mEq/100 mL	—
Mild oral	20–60 mEq PO daily divided	—
DKA prophylactic replacement	20–40 mEq/L in IV fluid as long as K <5.3	—

PO peak 1–2 h. IV effect immediate but redistribution into cells takes hours. Renal excretion (≥90%).

Excess serum K⁺ → cardiac arrhythmias up to and including asystole.

None directly.

!Cardiac arrhythmias from too-rapid administration or overshoot (peaked T waves, widened QRS, sine wave, asystole)
!Phlebitis with peripheral lines (always dilute)
!GI upset / ulceration with extended-release oral

★NEVER IV PUSH: 'KCl IV push' has killed patients; sentinel-event in nursing/pharmacy literature. Always dilute and infuse with continuous ECG.
★PERIPHERAL LIMIT: 10 mEq/h, ≤10 mEq/100 mL concentration — beyond this, central line.
★MAGNESIUM PARTNER: refractory hypokalemia almost always co-exists with hypomagnesemia — replace both. Mag deficiency causes urinary K wasting.
★DKA RULES (ADA): K <3.3 → hold insulin, replace K first, restart insulin once K >3.3; K 3.3–5.3 → start insulin + replace 20–30 mEq/L in fluid; K >5.3 → start insulin without K replacement.

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