Recommended Paracetamol (Acetaminophen) Dosing
The recommended dose of paracetamol (acetaminophen) for adults is 1000 mg (1 gram) per single dose, with a maximum of 4000 mg (4 grams) in a 24-hour period, administered at intervals of 4-6 hours. 1, 2
Adult Dosing Guidelines
- For adults and children 12 years and older, the standard single dose is 650-1000 mg every 4-6 hours, not to exceed 4000 mg in a 24-hour period 1, 2
- The optimal unit dose for adults is 1 gram, which provides the best analgesic effect 3
- The FDA-approved maximum daily dose remains 4000 mg, though some manufacturers have voluntarily reduced their recommended maximum to 3000-3250 mg 4
- Dosing intervals should be maintained at 4-6 hours between doses to maintain therapeutic effect 1, 3
Pediatric Dosing Guidelines
- Children 6 to under 12 years: 325 mg every 4 hours, not to exceed 5 doses (1625 mg) in 24 hours 2
- Children 4 to under 6 years: 240 mg every 4 hours, not to exceed 5 doses (1200 mg) in 24 hours 2
- Children 2 to under 4 years: 160 mg every 4 hours, not to exceed 5 doses (800 mg) in 24 hours 2
- For infants and children under 2 years: consult a doctor for appropriate dosing 2
- The recommended pediatric oral dose is 15 mg/kg every 4 hours, up to a total of 60 mg/kg/day 3
Route-Specific Considerations
- Oral administration: Standard dosing applies with rapid absorption, especially with effervescent formulations 3
- Intravenous paracetamol: Loading dose of 15-20 mg/kg, followed by 10-15 mg/kg every 6-8 hours 5
- Rectal administration: Higher loading doses (20-40 mg/kg) may be required due to poor bioavailability; 15 mg/kg if weight <10 kg 5
Special Populations
- Elderly patients: Some guidelines suggest reducing the maximum daily dose to 3000 mg, though the single dose maximum of 1000 mg remains the same 1
- Patients with liver disease: Paracetamol is contraindicated in those with hepatic insufficiency 3, 6
- Patients with chronic renal insufficiency: Paracetamol is the non-opiate analgesic of choice, and dosage reduction is usually not necessary 3, 6
Safety Considerations
- The toxic dose of paracetamol is generally considered to be 150 mg/kg or greater in a single acute ingestion (approximately 10 grams for most adults) 7
- Severe hepatotoxicity can occur with repeated supratherapeutic ingestions, even with doses just above 4 grams per day 7
- Patients with risk factors for hepatotoxicity (chronic alcohol consumption, pre-existing liver disease) should limit daily intake to 2000-3000 mg 7, 6
- Warning signs of toxicity include nausea, vomiting, abdominal pain, and elevated liver enzymes 1, 7
Clinical Pearls
- Paracetamol can be safely combined with NSAIDs for enhanced analgesic effect or to allow lower doses of each medication 3
- Paracetamol has minimal drug interactions due to its low level of plasma protein binding 3
- For patients requiring around-the-clock analgesia, sustained-release formulations (2000 mg) can provide 12-hour coverage 8
- Paracetamol is suitable as a first-line analgesic for mild to moderate acute pain in many adults with comorbidities including liver, kidney, cardiovascular disease, and gastrointestinal disorders 6