What is the recommended dosage of Panadol (acetaminophen) for a 5-day prescription?

Panadol (Acetaminophen) Dosing for 5-Day Prescription

For adults with normal liver and kidney function, prescribe acetaminophen 650-1000 mg every 4-6 hours as needed, not exceeding 4000 mg per 24 hours, though a more conservative maximum of 3000 mg daily is increasingly recommended to reduce hepatotoxicity risk. 1, 2

Standard Adult Dosing Algorithm

Single dose: 650-1000 mg per dose 1, 3

Dosing interval: Every 4-6 hours as needed 1, 2

Maximum daily dose:

• 4000 mg per 24 hours (FDA-approved maximum) 1, 2
• 3000 mg per 24 hours (increasingly recommended conservative limit) 1, 4

For a 5-day prescription, calculate total tablets based on expected frequency of use and counsel patients explicitly on the maximum daily limit. 1

Critical Safety Warnings for 5-Day Course

Hepatotoxicity risk increases with:

• More than 4000 mg in 24 hours 2
• Concurrent use of other acetaminophen-containing products 1, 2
• Three or more alcoholic drinks daily while using acetaminophen 2

Patients must be counseled to avoid all other acetaminophen products during the 5-day course, as inadvertent overdose from multiple sources is a common cause of hepatotoxicity. 1

Special Population Adjustments

Elderly patients (≥65 years):

• Reduce maximum to 3000 mg per day 1
• Consider lower starting doses due to smaller therapeutic window 5

Patients with liver disease or chronic alcohol use:

• Limit to 2000-3000 mg per day 1
• Contraindicated in hepatic insufficiency 3

Patients with renal insufficiency:

• Usually no dose reduction necessary 3
• Acetaminophen is the non-opioid analgesic of choice in chronic renal insufficiency 3

Practical Prescribing for 5 Days

For 500 mg tablets: Maximum 6 tablets per day (3000 mg) 2, 4

For 325 mg tablets: Maximum 10 tablets per day (3250 mg) 4

For 650 mg tablets: Maximum 6 tablets per day (3900 mg per monograph, though 3000 mg preferred) 4

Written instructions should specify:

• Exact dose and frequency 1
• Maximum number of tablets in 24 hours 2
• Warning to avoid all other acetaminophen products 1, 2
• Instruction to stop and seek care if skin reactions occur 2

Common Pitfalls to Avoid

Do not exceed 10 days of continuous use without medical supervision - the FDA label specifically limits use to 10 days unless directed by a physician 2

Avoid prescribing combination products with acetaminophen doses exceeding 325 mg per unit - this increases risk of inadvertent overdose 1

Do not assume patients understand "acetaminophen" equals "Panadol/Tylenol" - many patients inadvertently combine products containing the same active ingredient 1