II. Indications
III. Mechanism
- See Antihistamine
- H1 Receptor Antagonist
- Chlorpheniramine is an alkylamine First Generation Antihistamine with moderate Anticholinergic activity
- Dexchlorpheniramine is the active dextro-isomer of Chlorpheniramine (with twice its potency)
IV. Precautions
- Although FDA approved for children, FDA does not recommend routine Antihistamine use age <4 years
- Deaths have occurred in younger children related to Anticholinergic Toxicity
V. Medications
- Chlorpheniramine (Chlor-Trimeton, Aller-Chlor)
- Regular Release Tablets: 4 mg tablets
- Regular Release Syrup: 2 mg/5 ml
- Extended Release Tablets: 12 mg
- Dexchlorpheniramine (Polaramine, Polmon)
- Oral Solution: 2 mg/5 ml
VI. Dosing: Chlorpheniramine Regular Release Formulation
- Adult (age >=12 years): 4 mg orally every 4 to 6 hours
- Child (age 6 to 11 years): 2 mg orally every 4 to 6 hours
- Child (age 2 to 5 years): 1 mg orally every 4 to 6 hours (NOT fda approved)
VII. Dosing: Chlorpheniramine Timed Release Formulation
- Adult (age >=12 years): 8 mg orally every 8 hours OR 12 mg orally every 12 hours
- Child (age 6 to 11 years): 8 mg orally every 12 hours (NOT fda approved)
VIII. Dosing: Dexchlorpheniramine
- Adult (and child age>=12 years): 2 mg (or 1 tsp solution) every 4 to 6 hours as needed
- Child age 6 to 11 years: 1 mg (or 1/2 tsp solution) every 4 to 6 hours as needed
- Child age 2 to 5 years: 0.5 mg (or 1/4 tsp solution) every 4 to 6 hours as needed
IX. Adverse Effects
- See Antihistamine
- See Anticholinergic Toxicity
- Sedation
X. Safety
- Pregnancy category B
- Avoid in Lactation
XI. Resources
- Chlorpheniramine (DailyMed)
- Dexchlorpheniramine (DailyMed)
XII. References
- Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 146-7
- Hamilton (2020) Tarascon Pocket Pharmacopoeia
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| aller-chlor (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| ALLER-CHLOR 4 MG TABLET | Generic OTC | $0.02 each |