What is the recommended dose of paracetamol (acetaminophen) for adults and children?

Paracetamol (Acetaminophen) Dosing Guidelines

Adult Dosing

For adults, the standard dose is 650-1000 mg every 4-6 hours, with a maximum daily limit of 4000 mg per day, though a more conservative limit of 3000 mg per day is increasingly recommended for chronic use to reduce hepatotoxicity risk. 1

Standard Adult Dosing

• Single dose: 650-1000 mg every 4-6 hours 2, 3
• Maximum daily dose: 4000 mg (4 grams) in 24 hours 1, 2
• Conservative maximum for chronic use: 3000 mg per day 1
• Minimum interval between doses: 4 hours 4
• Maximum number of doses: 6 doses in 24 hours 4, 2

Critical Safety Considerations for Adults

• Combination products: When prescribing up to 4000 mg/day, explicitly counsel patients to avoid ALL other acetaminophen-containing products including over-the-counter cold remedies, sleep aids, and opioid combination products 1
• FDA combination product limit: Prescription combination products are limited to ≤325 mg acetaminophen per dosage unit 1, 5
• Hepatotoxicity threshold: Risk increases significantly with any dose exceeding 4000 mg in 24 hours 4

Special Adult Populations

Elderly Patients (≥60 years):

• Maximum daily dose: Reduce to 3000 mg per day or less 5
• Starting dose: Begin at lower end of dosing range (325 mg per dose) for frail elderly 5
• Dosing schedule: Regular scheduled dosing every 6 hours is more effective than as-needed administration 5
• No routine dose reduction needed: Despite reduced clearance, standard dosing is generally safe unless other risk factors present 3, 6

Patients with Liver Disease:

• Chronic liver disease/cirrhosis: Maximum 2000-3000 mg per day 1, 5
• Decompensated cirrhosis: Requires individualized dosing with physician consultation 6
• Hepatic insufficiency: Contraindicated in severe hepatic insufficiency 3

Chronic Alcohol Users:

• Maximum daily dose: Consider limiting to 2000-3000 mg per day 1, 4
• Risk: Hepatotoxicity can occur at doses ≤4000 mg in chronic alcohol users 1
• Avoid concurrent alcohol: Increases hepatotoxicity risk even at therapeutic doses 5

Renal Insufficiency:

• Chronic renal insufficiency: Usually no dose reduction necessary despite reduced clearance 3, 6
• Advanced kidney failure: May require individualized dosing 6

Pediatric Dosing

Children and Adolescents (≥12 years)

• Dose: 650 mg (20.3 mL of liquid formulation) every 4-6 hours 2
• Maximum: 6 doses in 24 hours, not exceeding 4000 mg total daily 4, 2
• Weight-based dosing: 10-15 mg/kg every 6 hours, maximum 60 mg/kg/day 4

Children 6 to <12 years

• Dose: 325 mg (10.15 mL) every 4 hours 2
• Maximum: 5 doses in 24 hours 2

Children 4 to <6 years

• Dose: 240 mg (7.5 mL) every 4 hours 2
• Maximum: 5 doses in 24 hours 2

Children 2 to <4 years

• Dose: 160 mg (5 mL) every 4 hours 2
• Maximum: 5 doses in 24 hours 2

Children <2 years

• Consult physician for appropriate dosing 2

General Pediatric Guidelines

• Standard oral dose: 10-15 mg/kg every 4-6 hours 3, 7
• Maximum daily dose: 60 mg/kg/day 4, 3, 7
• Optimal unit dose: 15 mg/kg every 4 hours in most children 3
• Chronic overdose risk: Exposures >140 mg/kg/day for several days carry risk of serious toxicity 4, 7

Intravenous Dosing (Adolescents)

• Loading dose: 15-20 mg/kg 4
• Maintenance: 10-15 mg/kg every 6-8 hours 4
• Maximum: 60 mg/kg/day or 4000 mg, whichever is lower 4

Route-Specific Considerations

Oral Administration

• Effervescent tablets: Provide more rapid absorption and onset of action compared to conventional tablets 3
• Bioavailability: Linear pharmacokinetics at therapeutic concentrations 3

Rectal Administration

• Adults: Require 35-45 mg/kg to achieve therapeutic plasma concentrations (10-20 μg/mL) 8
• Absorption: Slower and more irregular compared to oral route 3
• Not recommended as first-line due to unpredictable bioavailability 3, 8

Duration of Use

Acute Pain

• Short-term use (<14 days): Standard maximum of 4000 mg/day acceptable 6
• Typical duration: Few days or less for acute pain 9

Chronic Pain

• Recommended maximum: 3000 mg/day or less for chronic administration 1
• Monitoring: Regular liver enzyme monitoring (AST/ALT) when used chronically at higher doses 1
• Reassessment: Frequently reassess need for continued use and reduce dose when appropriate 1

Critical Warnings

Hepatotoxicity Risk

• Repeated supratherapeutic ingestions (doses just above therapeutic range) carry worse prognosis than acute single overdoses 1
• Definition of hepatotoxicity: Any AST increase; severe hepatotoxicity defined as AST >1000 IU/L 1
• Approximately 30% of acetaminophen overdose admissions involve repeated supratherapeutic ingestions 1

Common Pitfalls to Avoid

• Multiple acetaminophen-containing products: Failing to recognize acetaminophen in combination products leads to unintentional overdose 1
• Not tracking total daily intake: Using multiple products simultaneously without monitoring cumulative dose 1
• Inadequate dose adjustment: Not reducing dosage for patients with liver disease or chronic alcohol use 1

Multimodal Approach When Inadequate Relief

When acetaminophen alone provides insufficient pain control, add adjuvant therapies rather than exceeding the 3000 mg daily maximum: 1, 5

• Add topical lidocaine patches 5
• Consider regional nerve blocks 5
• Add NSAIDs (ibuprofen 10 mg/kg every 8 hours in adolescents) 4
• Reserve opioids only for breakthrough pain at lowest effective dose for shortest duration 5