# A nurse is preparing to administer liquid acetaminophen to a 6-year-old child who weighs 20 kg. The prescribed dose is 15 mg/kg every 6 hours. The medication concentration is 160 mg/5 mL. What is the correct volume to administer per dose?

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> subject: Pharmacology

## 문제

A nurse is preparing to administer liquid acetaminophen to a 6-year-old child who weighs 20 kg. The prescribed dose is 15 mg/kg every 6 hours. The medication concentration is 160 mg/5 mL. What is the correct volume to administer per dose?

## 보기

1. 1.5 mL
2. 7.5 mL
3. 9.4 mL **✔ 정답**
4. 12.5 mL

**정답: 3**

## 해설

Calculate dose: 20 kg × 15 mg/kg = 300 mg. Using concentration 160 mg/5 mL, volume = (300 mg × 5 mL) / 160 mg = 9.4 mL. Other options represent incorrect calculations.

## 심화 해설

Clinical Judgment
This question evaluates the core nursing skill of accurate medication dosage calculation. Weight-based calculation is essential for pediatric patients, and dosage errors can lead to serious consequences. The key to judgment is the stepwise calculation: weight (kg) → total required dose (mg) → liquid volume to administer (mL). The Critical Cue is accurately linking the two concentration details: the prescribed '15 mg/kg' and the '160 mg/5 mL' indicated on the vial.

Memory Tip: Remember pediatric drug calculations in 3 steps: **W**eight → **D**ose → **V**olume (**WDV**). 1) Weight (kg) × mg/kg = total mg, 2) (total mg) ÷ (mg/mL concentration) = mL needed. In this problem, since the concentration is given as mg/5mL, you can first convert to mg/mL (160÷5=32 mg/mL) and then calculate 300 mg ÷ 32 mg/mL = 9.375 mL to get the same answer.

KR vs US: In Korea, syringes that measure to one decimal place (0.1 mL) are common, whereas in the US, oral syringes or measuring cups are more frequently used. A volume like 9.4 mL can be accurately measured with a 10mL oral syringe. Also, in the US, a double-check with another nurse or pharmacist is often emphasized as standard practice after calculation.

## 임상 시나리오

Clinical Practice Guide
Acetaminophen is a commonly used antipyretic and analgesic in children. The maximum daily dose should generally not exceed 75 mg per kg of body weight (or divided into 4-5 doses). For this patient, administering 300 mg per dose every 6 hours results in a total daily dose of 1200 mg (60 mg per kg of body weight), which is within the safe range.

Caution: A common trap point in SATA (Select All That Apply) questions is "What to do after the calculation?" For example, correct answers may include "Recheck the calculation," "Verify with another nurse," or "Confirm the appropriateness of the prescribed dose with the physician (especially for first-time use)." Even for simple calculation questions, you must connect them to Safe Practice.

## 핵심 개념

- **Acetaminophen** — Common antipyretic and analgesic. No anti-inflammatory effect. Overdose can cause hepatotoxicity, so accurate dosage calculation is essential.
- **Weight-Based Dosing** — Standard method for determining drug dosage in pediatric and some adult patients. Provides accurate individualized dosing by prescribing a specific number of mg per kg of the patient's body weight (mg/kg).
- **Dosage Calculation** — One of the core competencies of a nurse. The process of accurately calculating the actual amount of medication to administer (number of tablets, liquid volume, etc.) using the prescribed dose, drug concentration, patient weight, and other factors.
- **Concentration** — Content per unit volume of the drug. In this problem, it is indicated as 160 mg/5 mL. For calculation purposes, it may be convenient to convert and use it as mg/mL (32 mg/mL).
- **Pediatric Medication Safety** — Principles and practices for safely administering medication to pediatric patients. Includes accurate weight measurement, double-checking, use of appropriate administration tools (such as oral syringes), and parent/caregiver education.

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