multi class comparison

IV Electrolyte Replacement: Potassium vs Magnesium vs Calcium — Rate, Route, Monitoring

Pushing IV potassium kills the patient. Pushing IV calcium too fast does the same. The NCLEX loves asking which electrolyte can never be given IV push and the safe infusion rates — one wrong answer choice and you've selected the lethal option.

Master this comparison — play it or drill it.

Play the gamePractice questions on this

33 practice questions available

Practice now

Comparison

Side-by-side3 compared
Comparevs
Dimension
Potassium (K⁺)
Magnesium (Mg²⁺)
Calcium (Ca²⁺)
Class & mechanism
  • KCl — restores intracellular cation
  • MgSO₄ — cofactor, smooth-muscle relaxant
  • Ca gluconate/chloride — restores Ca²⁺
Indications
  • Hypokalemia
  • Hypomagnesemia
  • torsades de pointes
  • ★Preeclampsia/eclampsia seizure prophylaxis
  • Hypocalcemia
  • Cardioprotection in hyperkalemia
Route & administration
  • IV diluted via pump
  • PO with food
  • Central line if concentrated >10 mEq/hr
  • IV infusion or IM
  • loading then maintenance
  • IV slow push/infusion
  • central line preferred
Key assessment
  • ECG: peaked T waves = hyperkalemia
  • Deep tendon reflexes + respiratory rate
  • Trousseau & Chvostek signs
Monitoring
  • Continuous cardiac/ECG monitoring
  • Verify serum level before & after
  • Continuous cardiac/ECG monitoring
  • Verify serum level before & after
  • Continuous cardiac/ECG monitoring
  • Verify serum level before & after
Adverse effects
  • Phlebitis/burning at IV site
  • Flushing, hypotension, drowsiness
  • Bradycardia if pushed too rapidly
Toxicity / safety alert
  • ★NEVER IV push — dilute & infuse via pump
  • Toxicity: loss of DTRs, resp depression
  • ★Antidote = IV calcium gluconate
  • ★Extravasation then tissue necrosis
Contraindications & interactions
  • Oliguria/renal failure
  • K-sparing diuretics
  • Heart block
  • hold if DTRs absent
  • Incompatible w/ many IVs — precipitates
Patient teaching
  • Take oral dose with food
  • never crush ER
  • Report weakness or trouble breathing
  • Report numbness/tingling around mouth
Class & mechanism

Potassium (K⁺)

  • KCl — restores intracellular cation

Magnesium (Mg²⁺)

  • MgSO₄ — cofactor, smooth-muscle relaxant
Indications

Potassium (K⁺)

  • Hypokalemia

Magnesium (Mg²⁺)

  • Hypomagnesemia
  • torsades de pointes
  • ★Preeclampsia/eclampsia seizure prophylaxis
Route & administration

Potassium (K⁺)

  • IV diluted via pump
  • PO with food
  • Central line if concentrated >10 mEq/hr

Magnesium (Mg²⁺)

  • IV infusion or IM
  • loading then maintenance
Key assessment

Potassium (K⁺)

  • ECG: peaked T waves = hyperkalemia

Magnesium (Mg²⁺)

  • Deep tendon reflexes + respiratory rate
Monitoring

Potassium (K⁺)

  • Continuous cardiac/ECG monitoring
  • Verify serum level before & after

Magnesium (Mg²⁺)

  • Continuous cardiac/ECG monitoring
  • Verify serum level before & after
Adverse effects

Potassium (K⁺)

  • Phlebitis/burning at IV site

Magnesium (Mg²⁺)

  • Flushing, hypotension, drowsiness
Toxicity / safety alert

Potassium (K⁺)

  • ★NEVER IV push — dilute & infuse via pump

Magnesium (Mg²⁺)

  • Toxicity: loss of DTRs, resp depression
  • ★Antidote = IV calcium gluconate
Contraindications & interactions

Potassium (K⁺)

  • Oliguria/renal failure
  • K-sparing diuretics

Magnesium (Mg²⁺)

  • Heart block
  • hold if DTRs absent
Patient teaching

Potassium (K⁺)

  • Take oral dose with food
  • never crush ER

Magnesium (Mg²⁺)

  • Report weakness or trouble breathing

★ marks the fact that sets a column apart.

Clinical Pearl

Potassium is NEVER pushed; magnesium toxicity is reversed by calcium; all three demand telemetry — slow is safe.

⚡ Speed Sort This Table

Swipe to sort 76 clinical items into the right bucket

Component Topics

HypocalcemiaHyperkalemiaHypokalemia

Ready to master this comparison?

Get a personalized study plan built around this topic — free to try, no card needed.

Play the gamePractice questions on this
See all Fluid, Electrolyte & Acid-Base topics