Paracetamol

Simple Analgesic·Analgesia - Simple & NSAIDs

Mild-to-moderate pain, fever

PBSANALGESICPanadol, Panamax, Perfalgan (IV)500 mg tabletUNSCHEDULED+1

Max Dose

4 g/day

Half-life

2 h

Hepatotoxicity

IN OD

GI Risk

LOW

Rapid Summary

Overview

The foundational, universally prescribed analgesic and antipyretic. Safe for the stomach and kidneys, but lethally hepatotoxic in overdose.

Maximum Dose

Max 4 g/day (strictly 1 g q6h). Must be reduced in severe liver failure or malnourishment.

Clinical Focus

The leading cause of acute liver failure worldwide. Always calculate cumulative dose across all combo products (e.g., Panadeine).

Bottom Line

Paracetamol is the safest first-line analgesic and antipyretic for mild-moderate pain, but hepatotoxicity in overdose is the leading cause of acute liver failure and the therapeutic window is narrow.

Formulation & Access

Brand Names

Panadol, Panamax, Perfalgan (IV)

Oral Routes

Tablets/Capsules (500 mg). Modified Release (665 mg - Osteo). Oral liquid.

Parenteral

Pre-mixed vials (1 g/100 mL) for IV infusion. Suppositories for PR use.

Prescribing & PBS

Over The Counter (PO). S4 for IV.

Indications & Use

Primary

PBSTGA

Mild-to-moderate pain, fever.

Clinical Place

First step on the WHO analgesic ladder. Should be co-prescribed regularly with all opioids to enact 'opioid-sparing' synergy.

Quick reference

Class & Role

Simple Analgesic — The foundational, universally prescribed analgesic and antipyretic.

Route / Formulation

Tablets/Capsules (500 mg). Modified Release (665 mg - Osteo). Oral liquid. (Panadol, Panamax, Perfalgan (IV))

Usual Dose & Max

PO / IV 500 mg - 1 g q4-6h. Max 4 g/day.

Key Indication Doses

Pain / Fever (Adults): PO / IV 500 mg - 1 g q4-6h. Max 4 g/day. Elderly / Frail / < 50 kg: Max 3 g/day (or 60 mg/kg/day). Severe Hepatic Impairment: Max 2-3 g/day or avoid entirely if acute fulminant failure.

Best Uses

Paracetamol is the safest first-line analgesic and antipyretic for mild-moderate pain, but hepatotoxicity in overdose is the leading cause of acute liver failure and the therapeutic window is narrow.

Avoid / Cautions

Acute fulminant liver failure, known hypersensitivity. Pregnancy Category A. The analgesic of choice in pregnancy and lactation.

Key Risks

Hepatic: Centrilobular hepatic necrosis (fatal liver failure) in overdose (>10g or >200mg/kg). Cardiovascular: IV administration can cause transient hypotension if infused too rapidly. Gastrointestinal: Zero risk of peptic ulcer disease or GI bleeding (unlike NSAIDs).

Key Interactions

Chronic heavy alcohol use depletes glutathione stores and upregulates CYP2E1, drastically increasing the amount of toxic NAPQI produced. Alcoholics are at high risk of liver failure even at standard 4g/day doses. IV Flucloxacillin. Co-administration with high-dose paracetamol causes severe High Anion Gap Metabolic Acidosis (HAGMA) due to 5-oxoproline accumulation (especially in malnourished women).

Monitoring

In overdose, plot serum paracetamol level against the Rumack-Matthew nomogram to dictate the need for Acetylcysteine (antidote). Monitor LFTs and INR (liver synthetic function). Ensure doses are spaced by at least 4 hours.

Clinical Pearl

Patients often don't realise 'Panadeine Forte' or cold/flu sachets contain 500mg of paracetamol. They take 4g of standard Panadol on top of their combo pills, accidentally overdosing to 8g/day. Always reconcile combos.

Access

Panadol, Panamax, Perfalgan (IV)500 mg tablet

Brand: Panadol, Panamax, Perfalgan (IV)
Formulation: Tablets/Capsules (500 mg)

Paracetamol

Simple Analgesic·Analgesia - Simple & NSAIDs

Mild-to-moderate pain, fever

PBSANALGESICPanadol, Panamax, Perfalgan (IV)500 mg tabletUNSCHEDULED+1

Max Dose

4 g/day

Half-life

2 h

Hepatotoxicity

IN OD

GI Risk

LOW

Rapid Summary

Overview

The foundational, universally prescribed analgesic and antipyretic. Safe for the stomach and kidneys, but lethally hepatotoxic in overdose.

Maximum Dose

Max 4 g/day (strictly 1 g q6h). Must be reduced in severe liver failure or malnourishment.

Clinical Focus

The leading cause of acute liver failure worldwide. Always calculate cumulative dose across all combo products (e.g., Panadeine).

Bottom Line

Paracetamol is the safest first-line analgesic and antipyretic for mild-moderate pain, but hepatotoxicity in overdose is the leading cause of acute liver failure and the therapeutic window is narrow.

Formulation & Access

Brand Names

Panadol, Panamax, Perfalgan (IV)

Oral Routes

Tablets/Capsules (500 mg). Modified Release (665 mg - Osteo). Oral liquid.

Parenteral

Pre-mixed vials (1 g/100 mL) for IV infusion. Suppositories for PR use.

Prescribing & PBS

Over The Counter (PO). S4 for IV.

Indications & Use

Primary

PBSTGA

Mild-to-moderate pain, fever.

Clinical Place

First step on the WHO analgesic ladder. Should be co-prescribed regularly with all opioids to enact 'opioid-sparing' synergy.

Quick reference

Class & Role

Simple Analgesic — The foundational, universally prescribed analgesic and antipyretic.

Route / Formulation

Tablets/Capsules (500 mg). Modified Release (665 mg - Osteo). Oral liquid. (Panadol, Panamax, Perfalgan (IV))

Usual Dose & Max

PO / IV 500 mg - 1 g q4-6h. Max 4 g/day.

Key Indication Doses

Best Uses

Paracetamol is the safest first-line analgesic and antipyretic for mild-moderate pain, but hepatotoxicity in overdose is the leading cause of acute liver failure and the therapeutic window is narrow.

Avoid / Cautions

Acute fulminant liver failure, known hypersensitivity. Pregnancy Category A. The analgesic of choice in pregnancy and lactation.

Key Risks

Key Interactions

Monitoring

Clinical Pearl

Access

Panadol, Panamax, Perfalgan (IV)500 mg tablet

Brand: Panadol, Panamax, Perfalgan (IV)
Formulation: Tablets/Capsules (500 mg)