Potassium Chloride Concentration in Standard Formulations
Standard intravenous potassium chloride (KCl) formulations contain 2 mEq of potassium per milliliter (2 mEq/mL). 1
FDA-Approved Concentrations
The FDA-labeled potassium chloride injection products are available in the following standardized concentrations 1:
- 10 mEq/100 mL = 0.1 mEq/mL (100 mEq/L)
- 10 mEq/50 mL = 0.2 mEq/mL (200 mEq/L)
- 20 mEq/100 mL = 0.2 mEq/mL (200 mEq/L)
- 20 mEq/50 mL = 0.4 mEq/mL (400 mEq/L)
- 40 mEq/100 mL = 0.4 mEq/mL (400 mEq/L)
Concentrated Formulations
Highly concentrated KCl vials (undiluted) typically contain 2 mEq/mL, which must be diluted before administration to prevent fatal cardiac complications 1. These concentrated vials should be removed from general clinical areas and stored in locked cupboards to prevent medication errors 2, 3.
Clinical Safety Considerations
- Concentrated KCl (≥400 mEq/L) is hypertonic and may cause vein damage, requiring central venous access for safe administration 1
- Peripheral infusions should be limited to ≤40 mEq/L concentration to minimize phlebitis and tissue injury 1
- Pre-diluted formulations are strongly preferred over manual dilution of concentrated vials to reduce preparation errors and accidental undiluted administration 2, 3
- A mandatory double-check policy must be applied to every step of potassium preparation and administration, including verification of concentration, dose, and infusion rate 2
Common Pitfall
The most dangerous error is administering undiluted concentrated KCl (2 mEq/mL) directly into a patient, which causes immediate cardiac arrest 3. This is why the British Medical Journal and multiple safety organizations recommend removing concentrated vials from patient care areas entirely 2, 3.