Recommended Dosage of Chlorpheniramine for Children
The recommended dosage of chlorpheniramine for children is age-dependent: children 6 to under 12 years should receive 1/2 tablet (break tablet in half) every 4 to 6 hours, not exceeding 3 whole tablets in 24 hours, while children under 6 years of age should not use this product. 1
Dosage Guidelines by Age Group
Children under 6 years
- Chlorpheniramine is not recommended for use in children under 6 years of age 1
- The FDA drug label specifically contraindicates its use in this age group due to safety concerns 1
Children 6 to under 12 years
- Dosage: 1/2 tablet every 4 to 6 hours 1
- Maximum daily dose: 3 whole tablets in 24 hours 1
- For parenteral administration in emergency settings (such as anaphylaxis): 2.5 mg IM or IV slowly 2
Children 12 years and older
- Dosage: 1 tablet every 4 to 6 hours 1
- Maximum daily dose: 6 tablets in 24 hours 1
- For parenteral administration in emergency settings: 10 mg IM or IV slowly 2
Pharmacokinetic Considerations
- Chlorpheniramine has a mean serum half-life of approximately 13.1 hours in children aged 6-16 years 3
- The volume of distribution is relatively large at about 7.0 L/kg, suggesting significant tissue binding 3
- Therapeutic serum concentrations range from 2.3 to 12.1 ng/mL for symptom suppression 3
- Despite similar maximum concentration (Cmax) across age groups, the area under the curve (AUC) is approximately 15-30% higher in older children 4
Clinical Applications
Allergic Reactions
- Chlorpheniramine is effective for managing allergic rhinitis symptoms in children 3
- In anaphylaxis, chlorpheniramine is considered a second-line therapy to epinephrine and should never be administered alone 2
- For acute allergic reactions requiring parenteral administration, the dosage is age-dependent:
Important Considerations and Precautions
- Sedation is a common adverse effect and appears to be more prevalent in younger children (2-5 years) 4
- Chlorpheniramine should not be used as the sole treatment for anaphylaxis, as H1 antihistamines are considered second-line therapy to epinephrine 2
- The combination of diphenhydramine and ranitidine (H1 and H2 blockers) is superior to diphenhydramine alone for managing anaphylaxis, but both are secondary to epinephrine 2
- For dystonic reactions, diphenhydramine (1-2 mg/kg or 25-50 mg/dose parenterally) can be administered instead of chlorpheniramine 5