What is the recommended dose of Paracetamol (PCM) for pain and fever management?

Paracetamol (Acetaminophen) Dosing for Pain and Fever Management

For adults, paracetamol should be dosed at 650-1000 mg every 4-6 hours, not exceeding 4000 mg per day, though a more conservative maximum of 3000 mg daily is increasingly recommended for chronic use to reduce hepatotoxicity risk. 1

Adult Dosing

Standard dosing:

• Single dose: 650-1000 mg every 4-6 hours 2, 3
• Maximum daily dose: 4000 mg (4 grams) in 24 hours 4, 1, 2
• Optimum unit dose for efficacy: 1000 mg (1 gram) 3

Conservative dosing for chronic use:

• Limit to 3000 mg daily for long-term management to reduce hepatotoxicity risk 1
• For patients with liver disease or chronic alcohol use, restrict to 2000-3000 mg daily 5, 1

Pediatric Dosing

Oral paracetamol:

• 10-15 mg/kg every 4-6 hours 4, 6, 3
• Maximum daily dose: 60 mg/kg/day 4, 6, 3
• The 15 mg/kg dose is more effective than lower doses and shows efficacy comparable to NSAIDs 7

Intravenous paracetamol (pediatric):

• Loading dose: 15-20 mg/kg 4
• Maintenance: 10-15 mg/kg every 6-8 hours 4

Rectal paracetamol (pediatric):

• Loading dose: 20-40 mg/kg (15 mg/kg if <10 kg) due to poor bioavailability from rectal route 4

Age-specific oral dosing (FDA-approved): 2

• Ages 12+ years: 650 mg every 4-6 hours (max 6 doses/24 hours)
• Ages 6-11 years: 325 mg every 4 hours (max 5 doses/24 hours)
• Ages 4-5 years: 240 mg every 4 hours (max 5 doses/24 hours)
• Ages 2-3 years: 160 mg every 4 hours (max 5 doses/24 hours)

Critical Safety Considerations

Hepatotoxicity risk:

• Repeated supratherapeutic ingestions (doses just above therapeutic range) carry worse prognosis than acute single overdoses, with approximately 30% of overdose admissions involving repeated supratherapeutic use 1
• In children, exposures greater than 140 mg/kg/day for several days carry risk of serious toxicity 6
• Single ingestions of more than 10 times the recommended dose are potentially toxic in children 6

Combination product warning:

• When prescribing paracetamol, explicitly counsel patients to avoid all other acetaminophen-containing products, including over-the-counter cold remedies and opioid combinations 1
• In fixed-dose combinations, acetaminophen should be limited to ≤325 mg per dosage unit 1

Clinical Context and WHO Pain Ladder

For mild pain (WHO Level I):

• Paracetamol is first-line for mild pain management 4
• Onset of action: 15-30 minutes 4

For moderate pain (WHO Level II):

• Paracetamol can be combined with weak opioids (codeine, tramadol) 4
• Tylenol #3 (acetaminophen 300 mg/codeine 30 mg): 1-2 tablets every 4 hours, not exceeding 12 tablets (3600 mg acetaminophen) in 24 hours 5

For severe pain (WHO Level III):

• Paracetamol may be continued with strong opioids as it provides significant additive analgesic effect 4, 6

Special Populations

Elderly patients:

• Start with lower doses: 650 mg every 4-6 hours rather than 1000 mg 5
• Clearance is reduced but dosage reduction usually not necessary unless hepatic insufficiency present 3

Patients with hepatic impairment:

• Reduce to 2000-3000 mg daily maximum 5, 1
• Paracetamol is contraindicated in hepatic insufficiency 3

Patients with chronic renal insufficiency:

• Paracetamol is the non-opioid analgesic of choice 3
• Usually no dosage reduction necessary 3

Pregnancy and lactation:

• Can be used safely during pregnancy and lactation 3

Common Pitfalls to Avoid

• Failing to recognize paracetamol in combination products, leading to unintentional overdose 1
• Using multiple acetaminophen-containing products simultaneously without tracking total daily intake 1
• Not adjusting dosage for patients with liver disease or chronic alcohol use 1
• Using subtherapeutic doses (≤10 mg/kg in children), which show inferior efficacy compared to NSAIDs 7
• Exceeding recommended dosing frequency by taking doses too close together 1