mEq (Milliequivalent): Meaning in Dosage Calculation
Shows the work. Every example is computed with the formula and numbered steps. For study and exam practice, not for patient care.
mEq: Milliequivalent: one thousandth of an equivalent, the unit electrolytes such as potassium are ordered and labeled in.
A milliequivalent (mEq) measures an electrolyte by its chemical combining power rather than its weight. Potassium chloride, for example, is ordered in mEq, and its label states the strength in mEq (per tablet, or per mL for a liquid).
Because an equivalent depends on the ion’s charge and weight, there is no single factor between mEq and mg: don’t convert one into the other unless the label gives both. When the order and the label are both in mEq, calculate exactly as with mg, using Desired ÷ Have × Vehicle.
Potassium chloride 40 mEq PO is ordered. Available: potassium chloride oral solution 20 mEq per 15 mL.
- Desired dose
- 40 mEq
- Have
- 20 mEq
- Vehicle
- 15 mL
- Give as
- mL (liquid or injection)
Formula Amount = desired ÷ have × vehicle.
- mL = desired ÷ have × vehicle.
- 40 mEq ÷ 20 mEq × 15 mL = 30 mL.
- 30 mL is exact, so no rounding is needed.
Answer 30 mL
The dosage calculator and the units/hr calculator both accept mEq.
Sources
- Clinical Calculations: With Applications to General and Specialty Areas — Elsevier (Kee, Marshall, et al.)
- DailyMed: drug labeling — U.S. National Library of Medicine