Medication Calculations

Medication arithmetic is a dose-safety task, not a mathematics exercise. A decimal-place or unit error can change the delivered exposure by tenfold or one-hundredfold. With a narrow-therapeutic-index, high-alert drug, the distance between the intended dose and a lethal dose may be very small. Before calculating, reconcile five things: the complete order, the patient-specific dosing variable, the product concentration, the units used by the pump or device, and the clinical appropriateness of the result. A neat calculation does not make an unsafe order safe. The administering nurse remains accountable for recognizing an implausible dose, clarifying an incomplete order, and withholding a dose believed to be unsafe.