Educational use only. Drug cards are AI-assisted study material for NCLEX preparation.
Potassium chloride (KCl, K-Dur, Klor-Con)
Mechanism of action
Replaces extracellular potassium, the principal intracellular cation responsible for membrane potential, cardiac and neuromuscular excitability, and acid-base balance. Used for hypokalemia from any cause — diuretics, GI losses, DKA correction, refeeding — and for prevention in chronic diuretic users.
Adverse effects
Life-threatening / NCLEX-tested
- Cardiac arrest from rapid IV push or bolus — IV potassium is NEVER pushed; it is ALWAYS infused via pump and concentration limits
- Severe hyperkalemia → peaked T waves, widened QRS, sine-wave ECG, ventricular fibrillation, asystole
- Severe burning and tissue necrosis with extravasation
- GI ulceration with extended-release tablets if not swallowed whole or if patient lies down right after
- Dysrhythmias with even moderate hyperkalemia
Side effects
Common — what to teach
- GI upset with oral form (take with food and a full glass of water)
- Burning at peripheral IV site (slow the rate, check the line)
- Diarrhea
- Mild nausea
- Bad taste with liquid form (mix with juice)
Food & drug interactions
ACE inhibitors, ARBs, and potassium-sparing diuretics (spironolactone, eplerenone, triamterene) compound hyperkalemia — review home meds before replacement. Salt substitutes are KCl-based — counsel patients. Rapid correction during DKA before insulin is given is dangerous (insulin drives K+ intracellularly).
Nursing implications
Assessment, monitoring, patient teaching
- ABSOLUTE RULES for IV potassium: NEVER push, NEVER give IV bolus, ALWAYS via pump, NEVER concentrations above 10 mEq/100 mL via peripheral (40 mEq/100 mL via central line per facility), maximum infusion rate typically 10 mEq/hour peripheral, 20 mEq/hour central with continuous ECG monitoring
- Verify patent IV — burning at the site means slow the rate or replace the line; extravasation causes severe tissue injury
- Two-nurse independent verification on every IV potassium order — high-alert medication
- PO: give with full glass of water; have patient sit upright for 10–30 minutes after extended-release tablets to prevent esophageal ulceration
- Recheck serum K+ after replacement, especially if multiple doses are given
- Verify urine output (≥ 30 mL/hr) before replacing — anuria is a contraindication
- Reconcile K+-raising drugs (ACE/ARB, spironolactone, NSAIDs) before ordering replacement
When to hold / contraindications
- Anuria or significant oliguria (< 30 mL/hr)
- Hyperkalemia (K+ > 5.0 — confirm hypokalemia is the actual problem)
- Severe acidosis with rising K+
- Active extravasation or infiltrated IV — restart the line first
- Bradyarrhythmia or new wide-complex rhythm during infusion
Memory anchor
"Never IV push, never bolus." 10 mEq/hr peripheral max; central line for higher concentrations; continuous ECG over 10 mEq/hr. Sit up after the pill.
Practice Potassium questions
Test your recall on real NCLEX-style pharmacology questions — with full rationales and an AI Coach for the parts you miss.