Chlorpheniramine
CHLOR-TRIMETON
Pronunciation: klor-fen-IR-a-meen
“Claw-Finn, Try mitt on”
Mitt resembles serotonin reuptake inhibitor symbol
What it isFirst-generation H1 antagonist; allergic rhinitis and cold remedies.
Why this oneLess sedating than diphenhydramine but remains common in multi-ingredient cold products.
What limits itAnticholinergic burden and sedation make it poor for older adults and unsafe before driving.
Chlorpheniramine prescription history
Animated chart of estimated U.S. prescriptions per year, H1 antihistamines (1944–2026). Chlorpheniramine enters in 1950 (estimated).
FDA-approved for
- allergy (~1949)
Principal riskAnticholinergic burden and sedation, so it is poor in the elderly
Classes and tags
Clinical profile
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
Dosing under review against the product label.
Available strengths
- ER tab 12 mg
- tab 4 mg
- sol 2 mg/5 mL
- inhaler 5 mg/mL
Contraindications
- To make a child sleepy
Cautions
- Ask a doctor before use if glaucoma
- Breathing problem (emphysema, chronic bronchitis)
- Difficulty urinating due to enlarged prostate
- Ask a doctor/pharmacist if taking sedatives or tranquilizers
- Avoid alcohol; alcohol, sedatives, tranquilizers may increase drowsiness
- Use caution driving or operating machinery
Adverse reactions
- Drowsiness
- Excitability (especially in children)
Pregnancy If pregnant, ask a health professional before use (Drug Facts).
Lactation If breast-feeding, ask a health professional before use (Drug Facts).
Cost
| Strength | #/mo | generic $/unit | CostPlus | |
|---|---|---|---|---|
| 12 mg | ER tab | per unit | not offered |
Serotonin and MAOI
Provisional washout figures
Evidence confidenceModerate
Open Chlorpheniramine in the interactive console ↗
Memory aids: interaction avatars
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Self-check
- How does chlorpheniramine sedation compare with diphenhydramine?
Less sedating. - Does less sedation make chlorpheniramine safe before driving?
No.