What is the recommended dose of Tylenol (acetaminophen) for a 74-pound adult?

Acetaminophen Dosing for a 74-Pound Adult

The recommended dose of acetaminophen for a 74-pound (33.6 kg) adult is 650-1000 mg every 4-6 hours as needed, not exceeding 3000-4000 mg per day total. 1

Weight-Based Dosing Considerations

For this unusually low-weight adult (74 pounds/33.6 kg), standard adult dosing can be used, but with careful attention to the maximum daily limit:

• Standard adult dose: 650-1000 mg every 4-6 hours
• Maximum daily dose: 3000-4000 mg (conservative maximum: 3000 mg)
• For this patient, consider using the lower end of the dosing range (650 mg) per dose

Dosing Algorithm

1. Initial dose: 650 mg (two 325 mg tablets or one 650 mg extended-release tablet)
2. Frequency: Every 4-6 hours as needed
3. Maximum daily dose: Do not exceed 3000 mg in 24 hours
4. Duration: Use for the shortest duration necessary to control symptoms

Important Safety Considerations

• The CDC and other guidelines recommend starting at the lowest effective dose for all medications 2
• Risk factors for acetaminophen toxicity include:
  • Exceeding the maximum daily dose of 4000 mg
  • Concurrent use of multiple acetaminophen-containing products
  • Consumption of 3 or more alcoholic beverages daily
  • Pre-existing liver disease 1

Monitoring and Precautions

• Monitor for signs of liver dysfunction: jaundice, right upper quadrant pain, fatigue, nausea, vomiting, and dark urine 1
• Avoid alcohol consumption while taking acetaminophen
• Be aware that many combination products (especially those with opioids) contain acetaminophen, which could lead to unintentional overdose 2

Special Considerations for Low-Weight Adults

While specific guidelines for low-weight adults are limited, the principles used in pediatric dosing can be considered:

• The adult dose is appropriate as long as it doesn't exceed what would be safe based on weight
• At 74 pounds (33.6 kg), even the maximum adult single dose of 1000 mg is below 30 mg/kg, which is within safe limits

Common Pitfalls to Avoid

• Using multiple acetaminophen-containing products simultaneously
• Failing to recognize acetaminophen in combination medications (especially prescription pain medications)
• Exceeding the maximum daily dose, particularly in patients with smaller body mass
• Not adjusting dosing in patients with liver impairment

Despite recent changes in manufacturer recommendations (some suggesting 3000 mg maximum daily dose), the evidence-based maximum remains 3000-4000 mg per day for adults with normal liver function 3. However, for this low-weight adult, the more conservative 3000 mg maximum is advisable.