# A 60-year-old client takes acetaminophen 650 mg every 6 hours for chronic knee osteoarthritis and asks if it is safe to add Tylenol PM at bedtime and a combination cold medicine that contains acetaminophen. Which response by the nurse is most appropriate?

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=375130&lang=en  
> language: en  
> subject: Medical Emergencies  
> category: PA

## Question

A 60-year-old client takes acetaminophen 650 mg every 6 hours for chronic knee osteoarthritis and asks if it is safe to add Tylenol PM at bedtime and a combination cold medicine that contains acetaminophen. Which response by the nurse is most appropriate?

## Option

1. Stop the scheduled acetaminophen and use only the cold medicine.
2. It is fine to use Tylenol PM nightly because nighttime doses do not count.
3. Stay under 4 grams of acetaminophen per 24 hours from all sources, or under 3 grams if you have liver disease or drink alcohol regularly; many over-the-counter combination products contain hidden acetaminophen, so read every label. **✔ Correct answer**
4. You may take all three together because acetaminophen has no maximum dose.

**Correct answer: 3**

## Explanation

Acetaminophen is the most common cause of acute liver failure in the United States, largely from inadvertent overdose using multiple combination products. Adult ceiling: 4 g per 24 hours from all sources for short-term use; 2 to 3 g per 24 hours for chronic users, alcohol use, malnutrition, or liver disease. Pediatric: 75 mg/kg/day not to exceed adult ceiling. Acetaminophen is hidden in many OTC products: cold-flu combos (DayQuil, NyQuil, Theraflu), opioid-acetaminophen (Percocet, Norco, Vicodin), Tylenol PM (acetaminophen + diphenhydramine), and many migraine and menstrual products. Teaching: (1) total daily acetaminophen from all sources, (2) read every OTC and Rx label for the word acetaminophen or APAP or paracetamol, (3) do not double-dose, (4) avoid alcohol, (5) report jaundice, dark urine, RUQ pain, persistent nausea or vomiting, (6) hepatotoxicity is biphasic — N/V/malaise within 24 hours, then asymptomatic, then RUQ tenderness and rising AST/ALT 24 to 72 hours, then encephalopathy and coagulopathy by 72 to 96 hours.

## In-depth explanation

The hidden-acetaminophen warning combined with the 4 g (or 3 g if liver/alcohol) ceiling is the universal NCLEX teaching point. Always sum acetaminophen from all sources.

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