What is the maximum recommended dose of paracetamol (acetaminophen) per day?

Maximum Daily Dose of Paracetamol (Acetaminophen)

The maximum recommended dose of paracetamol is 4000 mg (4 grams) per 24 hours for healthy adults, though increasingly conservative recommendations suggest limiting chronic use to 3000 mg per day to reduce hepatotoxicity risk. 1, 2, 3

Standard Dosing Parameters

For healthy adults:

• Maximum daily dose: 4000 mg per 24 hours 1, 2, 3
• Maximum single dose: 1000 mg 1, 2
• Typical dosing interval: 650-1000 mg every 4-6 hours 1, 3
• Maximum number of doses: Not to exceed 6 doses in 24 hours 3

The FDA-approved maximum of 4000 mg/day was established through the monograph process, though this limit is being reconsidered due to safety concerns. 4, 5

Conservative Dosing for Chronic Use

For patients requiring daily paracetamol beyond short-term use:

• Limit to 3000 mg per day maximum to minimize hepatotoxicity risk 4, 1
• The National Comprehensive Cancer Network specifically recommends this lower threshold for chronic administration 4, 1
• If pain control is inadequate at 3000 mg/day, add adjuvant analgesics or use multimodal approaches rather than increasing to 4000 mg/day 4

This conservative approach is critical because repeated supratherapeutic ingestions (doses just above therapeutic range) carry worse prognosis than acute single overdoses, accounting for approximately 30% of paracetamol overdose admissions. 4, 1, 2

High-Risk Populations Requiring Dose Reduction

Patients with liver disease:

• Limit to 2000-3000 mg daily for those with cirrhosis or chronic liver disease 4, 1, 2
• Paracetamol is contraindicated in hepatic insufficiency 6

Elderly patients (≥60 years):

• Some guidelines suggest reducing maximum daily dose to 3000 mg or less 1, 2
• Single dose maximum of 1000 mg remains unchanged 2
• However, no evidence supports routine dose reduction solely based on age; dosing should be individualized based on comorbidities 7

Chronic alcohol users:

• Exercise caution as hepatotoxicity can occur at doses ≤4000 mg 8
• Case series demonstrate severe hepatotoxicity and mortality with doses as low as 5-8.75 g/day in chronic alcohol users 8

Critical Safety Warnings

Hepatotoxicity risk:

• Severe liver damage may occur if an adult takes more than 6 doses in 24 hours or exceeds 4000 mg 3
• Elevated liver enzymes (AST >1000 IU/L defines severe hepatotoxicity) may indicate developing toxicity 4, 2
• Even therapeutic doses of 4 g/day for 14 days caused ALT elevations >3× normal in 31-41% of healthy adults in controlled trials 8

Combination products:

• The FDA mandates prescription combination products contain ≤325 mg paracetamol per dosage unit 4, 1, 2
• When prescribing up to 4000 mg/day, explicitly counsel patients to avoid ALL other paracetamol-containing products including over-the-counter cold remedies, sleep aids, and opioid combinations 4, 1
• Failing to recognize paracetamol in multiple products is a common cause of unintentional overdose 4

Common Pitfalls to Avoid

• Using multiple paracetamol-containing products simultaneously without tracking total daily intake 4
• Not adjusting dosage for patients with liver disease or chronic alcohol use 4
• Exceeding dosing frequency by taking doses too close together 4
• Assuming brand-name products have different limits: Generic manufacturers maintain 3900 mg maximum while some brands (Tylenol®) voluntarily reduced to 3000 mg, creating confusion 5