Chlorpheniramine
Chlorpheniramine is a first-generation antihistamine medication that provides relief from allergic symptoms by blocking histamine receptors. It is commonly used to treat seasonal allergies, hay fever, allergic conjunctivitis, and allergic skin reactions like hives.
Chlorpheniramine is an antihistamine used to relieve allergy symptoms such as sneezing, itching, watery eyes, and runny nose.
Key facts at a glance
- ATC
- R06AB04
- RxNorm
- 2400
- Generic
- Chlorpheniramine
- Class
- atc-r06
- Brands
- Zodryl DAC, Zodryl AC, Tuzistra, Chlor-Trimeton, Tuxarin, Aller-Chlor, Ventuss, Clorrelief, Tannic-12 S, Tussionex, Poly Hist PD, Wal-finate
- Availability
- otc
- Pregnancy
- B
- Lactation
- caution
- Half-life (h)
- 20
- Onset (min)
- 30
- Duration (h)
- 6
- Routes
- oral
- Forms
- tablet, extended-release tablet, chewable tablet, capsule, syrup, oral solution
- Regions
- United States, Canada, United Kingdom, Australia, European Union, India
- Monitoring
- none
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
- 4mg every 4-6 hours
- Maximum
- consult physician
- Frequency
- every 4-6 hours as needed
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 2mg every 4-6 hours
- Maximum
- consult physician
- Frequency
- every 4-6 hours as needed
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 2-4mg every 4-6 hours
- Maximum
- consult physician
- Frequency
- every 4-6 hours as needed
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
11 groupspregnancy
first trimesteravoid if possible
use only if clearly needed and benefits outweigh potential risks
regular prenatal care
Use with caution and monitor for adverse effects.
pregnancy
second trimesteruse lowest effective dose
avoid prolonged use, use only when benefits outweigh risks
regular prenatal monitoring
Use with caution and monitor for adverse effects.
pregnancy
third trimesteravoid near term
discontinue at least 2 weeks before delivery if possible
fetal monitoring in late pregnancy
Use with caution and monitor for adverse effects.
lactation
breastfeedinguse lowest effective dose
avoid high doses or prolonged use, monitor infant for sedation or irritability
observe infant for unusual drowsiness or irritability
Use with caution and monitor for adverse effects.
pediatric_age
under 2 yearsnot recommended
do not use in infants under 2 years due to risk of severe CNS depression
emergency medical attention if used
Use of this medication in this population requires careful consideration of risks and benefits.
pediatric_age
2 to 12 yearsweight-based dosing, do not exceed recommended maximum
use pediatric formulation, avoid adult formulations
monitor for excessive sedation or paradoxical excitement
Use with caution and monitor for adverse effects.
geriatric
elderlystart with lowest dose, consider dose reduction
use with caution due to increased sensitivity to anticholinergic effects
monitor for falls, confusion, urinary retention, constipation
Use with caution and monitor for adverse effects.
renal_impairment
mildno significant dose adjustment needed
monitor renal function periodically
periodic renal function monitoring
Use with caution and monitor for adverse effects.
renal_impairment
moderate to severereduce dose by 25-50%
use with caution, extended dosing intervals recommended
regular monitoring of renal function and drug accumulation
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateconsider dose reduction
use with caution, monitor for excessive sedation
monitor liver function tests periodically
Use with caution and monitor for adverse effects.
hepatic_impairment
severesignificant dose reduction recommended
use only if benefits outweigh risks, avoid prolonged use
close monitoring for sedation and adverse effects
Use with caution and monitor for adverse effects.
Statistics and clinical data
Commonly prescribed since
General prescribing information
Drug class
Drug class information
Common uses
Common therapeutic uses
Mechanism of action
Mechanism of action information
Treats allergic rhinitis, hay fever, allergic conjunctivitis, urticaria (hives), angioedema, and provides symptomatic relief from common cold symptoms including sneezing and rhinorrhea.
Acts as a competitive histamine H1 receptor antagonist, blocking the binding of histamine to these receptors and thereby reducing allergic response symptoms such as itching, swelling, and mucus production.
Causes drowsiness and sedation; avoid operating machinery. Has anticholinergic effects (dry mouth, blurred vision, constipation). Use with caution in elderly patients, those with narrow-angle glaucoma, or urinary retention. Alcohol and CNS depressants may enhance sedation. Available over-the-counter and as prescription formulations.
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 August 27, 2026. · Read our editorial policy