Acetaminophen
Acetaminophen is a widely used over-the-counter pain reliever and fever reducer that provides relief from mild to moderate pain and reduces fever.
A common pain reliever and fever reducer used for headaches, minor aches, and fever reduction.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- N02BE01
- Generic
- Acetaminophen
- Class
- acetaminophen
- Brands
- Tylenol, Panadol
- Availability
- behind_counter
- Pregnancy
- B
- Lactation
- safe
- Half-life (h)
- 2.5
- Onset (min)
- 30
- Duration (h)
- 6
- Routes
- oral, rectal, iv
- Forms
- tablet, capsule, suppository, injection
- Regions
- CN, US, EU, JP
- Monitoring
- liver-function
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
11 groupspregnancy
first trimesteravoid if possible
use only when clearly needed, avoid during first trimester unless benefits outweigh risks
regular prenatal care
Use with caution and monitor for adverse effects.
pregnancy
second trimesteruse lowest effective dose
use only when needed for fever or pain relief
regular prenatal care
Use with caution and monitor for adverse effects.
pregnancy
third trimesteravoid high doses near term
use only when needed, avoid near delivery
fetal monitoring in third trimester
Use with caution and monitor for adverse effects.
lactation
breastfeedingno adjustment needed
considered compatible with breastfeeding, use as needed
no specific monitoring required
pediatric_age
infants and childrenweight-based dosing essential
use pediatric formulation, do not exceed recommended dose
monitor for signs of overdose
geriatric
elderlyconsider renal and hepatic function
use appropriate dose based on kidney and liver function
monitor renal and hepatic function periodically
renal_impairment
mild to moderateno adjustment needed for mild impairment
use with caution, avoid prolonged use
monitor renal function
Use with caution and monitor for adverse effects.
renal_impairment
severereduce dose or increase dosing interval
use reduced dose, consider alternative analgesics
close monitoring of renal function and drug levels
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateuse lowest effective dose
avoid exceeding recommended dose, avoid with alcohol
monitor liver function tests
Use with caution and monitor for adverse effects.
hepatic_impairment
severeavoid use
contraindicated in severe hepatic impairment or active liver disease
liver function monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
alcohol_users
chronic alcohol useavoid completely
avoid in chronic alcohol users due to increased hepatotoxicity risk
liver function tests
Use of this medication in this population requires careful consideration of risks and benefits.
Statistics and clinical data
Introduced for medical use
Year Acetaminophen was first approved for medical use
Drug class
Analgesic and antipyretic classification
Common uses
Primary therapeutic applications
Safety profile
Safety and toxicity information
Used to treat mild to moderate pain including headaches, muscle aches, backaches, toothaches, and menstrual cramps; also reduces fever; often used for common colds, flu, and post-vaccination symptoms.
Acts primarily in the central nervous system to inhibit cyclooxygenase (COX) enzymes, blocking pain signals and resetting the hypothalamic temperature set-point to reduce fever; has minimal anti-inflammatory effects in peripheral tissues compared to NSAIDs.
Generally well-tolerated when used as directed but can cause serious liver damage with excessive doses or alcohol use; avoid combining with alcohol; do not exceed 4,000mg daily in adults; always check other medications for hidden acetaminophen to prevent accidental overdose.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 22, 2026. · Read our editorial policy