Acetylcysteine
Acetylcysteine is a mucolytic agent and antidote medication primarily used to treat acetaminophen overdose and to help relieve respiratory conditions by thinning mucus. It works by replenishing glutathione levels in the liver, which helps prevent liver damage from toxic metabolites. This medication is available in oral, intravenous, and inhaled formulations depending on the indication.
Acetylcysteine is used as an antidote for acetaminophen overdose and as a mucolytic to help clear respiratory secretions.
Key facts at a glance
- ATC
- R05CB01
- RxNorm
- 197
- Generic
- Acetylcysteine
- Class
- atc-r05
- Brands
- Acetadote
- Availability
- rx
- Lactation
- unknown
- Routes
- ophthalmic, oral
- Forms
- injection, solution, capsule, tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
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 trimesterno specific adjustment
use only if clearly needed and benefits outweigh risks
regular prenatal monitoring
Use with caution and monitor for adverse effects.
pregnancy
second trimesterno specific adjustment
use only if benefits outweigh potential risks
standard prenatal care
Use with caution and monitor for adverse effects.
pregnancy
third trimesterno specific adjustment
use only if clearly needed
fetal monitoring in late pregnancy
Use with caution and monitor for adverse effects.
lactation
breastfeedingno adjustment needed
generally considered compatible with breastfeeding
none specific
pediatric_age
children 2 12 yearsweight-based dosing required
use weight-based dosing; oral formulation preferred for mucolysis
monitor for nausea and vomiting
pediatric_age
infants neonatesreduced dose required
use with extreme caution; limited safety data
close monitoring required
Use with caution and monitor for adverse effects.
geriatric
elderly over 65no specific adjustment; start low
use standard dosing but monitor for adverse effects
monitor renal and hepatic function
Use with caution and monitor for adverse effects.
renal_impairment
mild to moderateno specific adjustment for mucolytic use
use with caution; monitor renal function
monitor renal function tests
Use with caution and monitor for adverse effects.
renal_impairment
severeuse with caution
use only when benefits outweigh risks
close monitoring of renal function
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateno standard adjustment
use with caution in hepatic impairment
monitor liver function tests
Use with caution and monitor for adverse effects.
hepatic_impairment
severeuse with extreme caution
use only under close medical supervision
frequent liver function monitoring
Use with caution and monitor for adverse effects.
Statistics and clinical data
FDA Approval Year
Acetadote FDA approval for acetaminophen overdose
Drug class
ATC classification for acetylcysteine
Primary indication
Primary therapeutic use
Mechanism of action
Pharmacological mechanism
Treatment of acetaminophen (paracetamol) overdose to prevent hepatotoxicity; mucolytic therapy for respiratory conditions with thick mucus such as chronic bronchitis, cystic fibrosis, and COPD exacerbations.
Restores hepatic glutathione levels, which conjugates and neutralizes toxic acetaminophen metabolites. As a mucolytic, it breaks disulfide bonds in mucus proteins, reducing viscosity.
Most effective when administered within 8-10 hours of acetaminophen ingestion. May cause GI upset, hypersensitivity reactions (especially IV), or bronchospasm when inhaled. Requires dose adjustment in hepatic impairment.
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 26, 2026. · Read our editorial policy