Pheniramine
Pheniramine is a first-generation antihistamine that blocks histamine H1 receptors to provide relief from allergic reactions. It is commonly used to treat seasonal allergies, allergic rhinitis, conjunctivitis, and skin conditions such as urticaria (hives).
Pheniramine is an antihistamine used to treat allergic conditions like hay fever, hives, and allergic eye inflammation.
Key facts at a glance
- ATC
- unclassified
- RxNorm
- unknown
- Generic
- Pheniramine
- Class
- atc-d04
- Brands
- Naphcon A, Opcon-A, Alahist D
- Availability
- otc
- Pregnancy
- C
- Lactation
- caution
- Half-life (h)
- 4
- Onset (min)
- 30
- Duration (h)
- 5
- Routes
- oral, ophthalmic
- Forms
- tablet, capsule, syrup, eye drop
- Regions
- United States, United Kingdom, Canada, Australia, Germany, France, India, Japan
- Monitoring
- drowsiness, dry mouth, dizziness, blurred vision
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
8 groupspregnancy
first trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks
regular fetal monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
third trimesteravoid
avoid use especially near term as may cause uterine contractions
fetal monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
breastfeedinguse lowest effective dose
use only if clearly needed and avoid high doses
monitor infant for excessive drowsiness or irritability
Use with caution and monitor for adverse effects.
geriatric
elderlyreduce starting dose
use with caution due to increased sensitivity to anticholinergic effects
monitor for sedation, dizziness, confusion, urinary retention
Use with caution and monitor for adverse effects.
pediatric_age
children 2 to 6 yearsuse reduced dose
use only under medical supervision
monitor for paradoxical excitation and respiratory depression
Use with caution and monitor for adverse effects.
pediatric_age
children under 2avoid
not recommended for children under 2 years of age
close monitoring for respiratory depression
Use of this medication in this population requires careful consideration of risks and benefits.
renal_impairment
mild to moderatedose reduction may be required
use with caution and monitor renal function
monitor renal function tests
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderatedose reduction may be required
use with caution and monitor liver function
monitor liver function tests
Use with caution and monitor for adverse effects.
Statistics and clinical data
Drug class
Pheniramine belongs to the pyridine derivative class of antihistamines
Common uses
Ophthalmic formulations for relieving ocular itching and redness due to allergies
Common formulations
Available as topical eye drops, often in combination with decongestants
Mechanism of action
Blocks H1 histamine receptors to reduce allergic symptoms
Pheniramine is used to treat allergic rhinitis (hay fever), allergic conjunctivitis, urticaria (hives), pruritus (itching), and other allergic skin reactions. It may also be used as part of combination products for the common cold.
As an H1-receptor antagonist, pheniramine competitively blocks histamine at H1 receptor sites, reducing allergic symptoms such as itching, swelling, redness, and runny nose. It also possesses anticholinergic properties that help dry respiratory secretions.
Common side effects include drowsiness, dry mouth, and blurred vision. Due to its sedative effects, caution is advised when operating machinery or consuming alcohol. It should be used with caution in patients with glaucoma, urinary retention, or prostate enlargement. Consult a healthcare provider before use during pregnancy or breastfeeding.
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 25, 2026. · Read our editorial policy