At what core temperature should a fever be treated with paracetamol (acetaminophen, Panadol) in adults and children?

At What Temperature Should You Absolutely Treat Fever with Panadol?

There is no absolute temperature threshold at which paracetamol (Panadol) must be given; instead, treat fever when it causes discomfort or in specific high-risk conditions (intracerebral hemorrhage, bacterial meningitis with intracranial hypertension), regardless of the exact number on the thermometer.

General Principle: Treat Discomfort, Not the Number

• International guidelines recommend treating fever in children based on the presence of discomfort rather than a predefined temperature cutoff 1.
• Paracetamol administration in febrile children significantly relieves discomfort (85% had severe discomfort before treatment vs. 14% after), and this relief is not strictly correlated with the degree of temperature reduction 2.
• Fever alone, without discomfort or pain, does not require treatment 1.
• Paracetamol is both effective and advisable when there is a combination of fever and pain, but doctors should show caution about advising it for children who have fever as the only symptom 1.

When Paracetamol Is Absolutely Indicated (Regardless of Specific Temperature)

Critical Neurological Conditions

• Intracerebral hemorrhage with any fever: The American Heart Association recommends aggressive antipyretic therapy to maintain normothermia (36–37°C) because fever duration is directly proportional to poor prognosis and independently predicts unfavorable outcomes 3.
• Bacterial meningitis with intracranial hypertension: Targeted temperature management at 34–36°C should be considered, with paracetamol as first-line therapy 4.

Septic Patients: A Nuanced Approach

• In infected ICU patients, higher temperature peaks of 38–38.4°C (UK data) or 39–39.4°C (Australia/New Zealand data) correlate with improved outcomes, suggesting fever may be protective against bacterial replication 4, 5.
• Paracetamol in septic patients lowers temperature by only approximately 0.3°C and does not reduce mortality or ICU length of stay 4, 5.
• For bacterial meningitis without intracranial hypertension, maintaining normothermia (allowing fever) is preferred; induced hypothermia worsens outcomes 4, 5.

Non-Infected ICU Patients

• Maintaining peak temperatures between 37.5–37.9°C during the first 24 hours is associated with better outcomes compared with higher peaks 5.

Practical Dosing When Treatment Is Indicated

Adults

• Standard regimen: 650–1000 mg orally every 4–6 hours, not exceeding 4 g per day 5.
• Optimal single dose for antipyresis: 1000 mg (higher than 500 mg) yields the greatest temperature-lowering effect 5.
• Onset of fever reduction begins within a few hours; maximal effect may take up to 4 hours 5.
• Average temperature drop is modest, about 0.26°C within the first 4 hours 5.

Children

• 15 mg/kg orally when discomfort is present 6.
• Paracetamol results in significantly higher rate of temperature fall (0.33°C/h vs. 0.07°C/h with placebo) and percentage reduction during the first four hours 6.
• After 4 hours, 46.6% of children become afebrile with paracetamol vs. 12.1% with placebo 6.

When Paracetamol Is Relatively Ineffective

• Paracetamol is relatively ineffective when baseline temperature exceeds 38°C (100.4°F) 5.
• Highly febrile young children with and without invasive bacterial infections who receive therapeutic doses experience significant temperature drop after 60–90 minutes but do not commonly become completely afebrile 7.
• The degree of temperature reduction is age-dependent (younger children have greater drops) and does not distinguish between infectious outcomes 7.

Management of Persistent High-Grade Fever

• Add a second-line NSAID (e.g., ibuprofen) if fever remains above 38.9°C after an adequate paracetamol dose 5.
• The combination paracetamol 500 mg/ibuprofen 150 mg is more effective than paracetamol 1000 mg alone in patients with bacterial fever at 1 hour (48.6% vs. 33.6% achieving primary endpoint) 8.
• Physical cooling methods should be employed alongside pharmacologic therapy 5.
• Ensure adequate hydration (up to 2 L per day) to prevent dehydration 5.

Common Pitfalls to Avoid

• Do not treat fever prophylactically to prevent febrile convulsions; paracetamol has been proven ineffective for this indication 1.
• Do not withhold paracetamol due to concerns about masking infection; the drug does not prolong fever duration in children with uncomplicated respiratory infections 6.
• Do not exceed 4 g per day in adults to prevent hepatotoxicity 5.
• There are indications that inhibiting fever through paracetamol can adversely affect the immune response, though clinical significance remains uncertain 1.

Special Obstetric Consideration

• For medical termination of pregnancy with misoprostol, give 650–1000 mg paracetamol 30–60 minutes before misoprostol to prevent prostaglandin-induced fever, and do not withhold it if fever develops 9, 5.