Acetaminophen (Tylenol)

What Is Acetaminophen?

Acetaminophen (called paracetamol outside the US) is one of the most commonly used medications for pain and fever. Unlike NSAIDs, it doesn't reduce inflammation but can be effective for many types of pain. It's generally gentle on the stomach but requires caution regarding liver safety.¹

How It Works²

• Mechanism not fully understood
• Works centrally (brain/spinal cord)
• Does NOT reduce inflammation
• Reduces fever
• Raises pain threshold

Uses

• Mild to moderate pain
• Headaches
• Osteoarthritis (mild cases)
• Dental pain
• Fever reduction
• When NSAIDs are contraindicated

Dosing³

• Regular strength: 325 mg per tablet
• Extra strength: 500 mg per tablet
• Typical adult dose: 650-1000 mg every 6 hours
• Maximum: 3000 mg/day (some say 4000 mg)
• Lower max for alcohol users, liver issues

Advantages

• Generally well tolerated
• Doesn't irritate stomach
• Safe for most people
• Available without prescription
• Can combine with NSAIDs
• Safe in pregnancy (most trimesters)

Liver Safety—Critical

• Can cause liver damage in overdose
• Leading cause of liver failure
• Many products contain acetaminophen
• Check all medications for acetaminophen
• Avoid with heavy alcohol use
• Don't exceed recommended dose

Hidden Sources of Acetaminophen

• Cold and flu medications
• Sleep aids (PM products)
• Prescription pain medications (Vicodin, Percocet)
• Migraine medications
• Always check labels

Who Should Be Cautious

• Liver disease
• Heavy alcohol use (3+ drinks/day)
• Taking multiple acetaminophen products
• Malnutrition

Effectiveness for Chronic Pain

• Often less effective than previously thought
• May help mild osteoarthritis
• Less effective for back pain
• Trial it—responses vary
• Safest as first-line option

References

1. Conaghan PG, Arden N, Avouac B, et al. Safety of paracetamol in osteoarthritis: what does the literature say? Drugs Aging. 2019;36(Suppl 1):7-14.
2. Graham GG, Davies MJ, Day RO, et al. The modern pharmacology of paracetamol: therapeutic actions, mechanism of action, metabolism, toxicity and recent pharmacological findings. Inflammopharmacology. 2013;21(3):201-232.
3. Machado GC, Maher CG, Ferreira PH, et al. Efficacy and safety of paracetamol for spinal pain and osteoarthritis: systematic review and meta-analysis. BMJ. 2015;350:h1225.