# A pediatric nurse is preparing to administer acetaminophen to a 6-year-old child weighing 20 kg. The physician's order states "acetaminophen 15 mg/kg PO q6h PRN for fever >101°F." The available medication is acetaminophen oral suspension 160 mg/5 mL. How many milliliters should the nurse administer per dose?

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> subject: Pharmacology

## 문제

A pediatric nurse is preparing to administer acetaminophen to a 6-year-old child weighing 20 kg. The physician's order states "acetaminophen 15 mg/kg PO q6h PRN for fever >101°F." The available medication is acetaminophen oral suspension 160 mg/5 mL. How many milliliters should the nurse administer per dose?

## 보기

1. 1.9 mL
2. 7.5 mL
3. 9.4 mL **✔ 정답**
4. 12.5 mL

**정답: 3**

## 해설

Calculate total dose: 20 kg × 15 mg/kg = 300 mg. Using concentration 160 mg/5 mL, set proportion: 160 mg/5 mL = 300 mg/X mL → X = 9.375 mL ≈ 9.4 mL. Other options result from incorrect weight or concentration calculations.

## 심화 해설

Core Nursing Explanation
**Key Concept Analysis**: This question tests the essential nursing skill of pediatric medication dosage calculation. The core principles involve calculating a weight-based dose and then converting that dose into a volume using the concentration of the available medication. The formula is: Key Point! (Weight in kg) × (Ordered mg/kg) = Total Dose in mg. Then, use the ratio (Available mg / Available mL) = (Total Dose mg / X mL) to solve for X.

**Answer Rationale**: Let's break it down step-by-step:

- **Calculate the total dose in milligrams (mg)**: The child weighs 20 kg, and the order is for 15 mg per kg. So, 20 kg × 15 mg/kg = 300 mg.

- **Determine the concentration of the available medication**: The oral suspension is 160 mg per 5 mL. This means every 5 mL of liquid contains 160 mg of acetaminophen.

- **Set up a proportion to find the volume (mL)**:

160 mg / 5 mL = 300 mg / X mL

Cross-multiply: 160 mg × X mL = 300 mg × 5 mL

160X = 1500

X = 1500 / 160

X = 9.375 mL

- **Round appropriately for safe administration**: Using a standard oral syringe, we round to the nearest tenth: 9.4 mL. This is the correct volume the nurse should draw up.

**Distractor Analysis**:

Watch out for confusion!

- **Option 1 (1.9 mL)**: This is likely a result of using the concentration incorrectly (e.g., 5 mL/160 mg) or a decimal place error.

- **Option 2 (7.5 mL)**: This is a common error where the nurse might calculate 300 mg and then mistakenly use the concentration as "per 1 mL" (160 mg/mL) instead of "per 5 mL." 300 mg / 40 mg/mL (if misreading 160mg/5mL as 160mg/1mL) would give 7.5 mL.

- **Option 4 (12.5 mL)**: This could result from forgetting the weight-based calculation and using the adult dose or a standard dose, or from an incorrect proportion setup (e.g., 5 mL/160 mg = X mL/300 mg).

**Related Concepts**: This calculation is fundamental for safe pediatric practice. Always remember the "rights" of medication administration: right patient, right drug, right dose, right route, right time, and right documentation. Double-checking your math is a critical part of the "right dose." For pediatric suspensions, always shake the bottle well to ensure uniform concentration before drawing up the dose.

Concept Summary

| Step | Action | Example Calculation |
| --- | --- | --- |
| 1. Find Total Dose | Weight (kg) × Ordered dose (mg/kg) | 20 kg × 15 mg/kg = 300 mg |
| 2. Identify Concentration | Read drug label (Amount of drug / Volume) | 160 mg / 5 mL |
| 3. Set Up Proportion | (Available mg / Available mL) = (Total Dose mg / X mL) | 160 mg / 5 mL = 300 mg / X mL |
| 4. Solve for X (mL) | Cross-multiply and divide | X = (300 mg × 5 mL) / 160 mg = 9.375 mL |
| 5. Round Safely | Use appropriate measuring device (oral syringe) | Round to 9.4 mL |

Anatomy, Physiology & Pharmacology Points
**Acetaminophen (Tylenol)**: A common antipyretic (fever-reducer) and analgesic (pain-reliever). It works primarily in the central nervous system to inhibit prostaglandin synthesis. Key Point! Unlike NSAIDs (e.g., ibuprofen), it has minimal anti-inflammatory effects. The maximum daily dose for children is typically 75 mg/kg/day, not to exceed 4,000 mg/day for adults. **Critical nursing consideration**: Hepatotoxicity (liver damage) is the primary risk with overdose.

Memory Tips

- **Dose Calc Mnemonic: "DDC"** - **D**esired Dose, **D**ivided by **C**oncentration. In this case, Desired Dose = 300 mg. Concentration = 160 mg/5 mL = 32 mg/mL. 300 mg / 32 mg/mL = 9.375 mL.

- **Double-Check Rule**: Always have another nurse verify high-risk or calculated doses, especially for pediatric and IV medications.

- **Unit Awareness**: Write down units (kg, mg, mL) at every step to avoid mixing them up.

High-Frequency NCLEX Topics
Pediatric dosage calculation is a **must-know** topic for the NCLEX-RN. Expect questions involving:

- Weight-based calculations (mg/kg).

- Liquid concentration conversions (mg/mL).

- IV drip rate calculations (mL/hr, gtt/min).

- Safe dose range checks (Is the ordered dose within the recommended range?).

Watch Out for Question Variations!
The NCLEX can test this core skill in many ways:

- **Priority Intervention**: "After calculating the dose, which action should the nurse take *first*?" (Answer: Verify the calculation with another nurse or reference.)

- **Safety**: "The nurse calculates the dose as 9.4 mL. The parent states they usually give 'one teaspoonful.' What is the nurse's best response?" (Answer: Educate that 1 teaspoon (tsp) is approximately 5 mL, so 9.4 mL is nearly 2 teaspoons, and the dose must be measured accurately with the provided syringe.)

- **Maximum Daily Dose**: "The child receives this dose (15 mg/kg q6h). What is the total 24-hour dose in mg/kg, and is it safe?" (Calculate: 15 mg/kg × 4 doses = 60 mg/kg/day. Compare to safe range, e.g., 75 mg/kg/day – it is safe.)

## 임상 시나리오

Nursing Clinical Practice Guide
**Clinical Scenario**: You are a nurse on a pediatric unit. A 6-year-old patient, Jamie, was admitted with pneumonia. Jamie's temperature is now 102.2°F (39°C), and they are uncomfortable. The physician's PRN order for acetaminophen is now indicated.

**Nursing Intervention Strategy**:

- **Assessment**: Confirm the patient's identity using two identifiers. Assess current temperature, pain level, weight (verify the 20 kg in the chart is current), and any history of liver problems or allergies.

- **Planning**: Calculate the dose as practiced (9.4 mL). Plan to use an oral syringe for precise measurement.

- **Implementation**:

- Shake the acetaminophen oral suspension bottle well for at least 15 seconds.

- Draw up 9.4 mL into an oral syringe.

- Administer the medication, ensuring the child swallows it. You may mix it with a small amount of juice or applesauce if approved and if the child will take the full dose.

- Document the time, dose, route, and reason for administration (fever >101°F).

- **Evaluation**: Reassess the patient's temperature and comfort level in 30-60 minutes. Document the effectiveness.

**Patient Safety and Precautions**:

- **Hepatotoxicity Risk**: Educate parents/caregivers that acetaminophen is in many cold/cough medicines. **Never** combine medications without checking labels to avoid accidental overdose.

- **Accurate Measurement**: Stress that kitchen spoons (teaspoons, tablespoons) are not accurate. Always use the measuring device (syringe, cup) provided with the medication.

- **Contraindications**: Do not administer if the child has severe liver disease or a known allergy to acetaminophen.

Nursing Procedure & Medication Flow
**Administering Pediatric Oral Liquids**:

- Perform hand hygiene.

- Verify the **"Rights" of Medication Administration**.

- Calculate dose and have a second nurse verify if required by policy.

- Shake the suspension.

- Draw up the correct volume, removing air bubbles.

- Place the child in an upright or semi-Fowler's position to prevent aspiration.

- Administer the medication slowly, allowing the child to swallow.

- Offer a sip of water or preferred drink afterward if allowed.

- Document immediately.

A Word from Your Senior Nurse
"Medication math can feel stressful, but it's one of the most concrete ways we protect our patients. In the real world, you'll often use a calculator or dose-calculation software, but *understanding the underlying math is your safety net*. Always ask yourself, 'Does this number make sense?' For a 20 kg child, 9.4 mL of a common suspension is a reasonable volume. If you calculated 1.9 mL or 12.5 mL, that should trigger a mental alarm to recalculate. This critical thinking, linking numbers to real-world expectations, is what separates a good nurse from a great one. You've got this!"

## 핵심 개념

- **Acetaminophen** — An antipyretic and analgesic medication that works centrally to reduce fever and pain. Primary concern is hepatotoxicity with overdose.
- **Weight-Based Dosing** — The standard method for calculating pediatric medication doses, using the child's weight in kilograms (mg/kg).
- **Oral Suspension** — A liquid dosage form where drug particles are suspended in a liquid. Must be shaken well before administration to ensure uniform dose.
- **Proportion** — A mathematical equation stating that two ratios are equal, used to solve for an unknown quantity in medication calculations.
- **PRN Order** — A medication order meaning "as needed." The nurse uses clinical judgment to administer based on specified criteria (e.g., fever >101°F).

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