What is the recommended dose of chlorpheniramine (antihistamine) maleate in children?

Recommended Dosage of Chlorpheniramine Maleate in Children

The recommended oral dose of chlorpheniramine maleate for children is age-dependent: children 6-12 years should take 1/2 tablet (2 mg) every 4-6 hours, not exceeding 3 tablets in 24 hours, while children under 6 years should not use oral chlorpheniramine. 1

Oral Dosing Guidelines

• For children 12 years and older: 1 tablet (4 mg) every 4-6 hours, not exceeding 6 tablets in 24 hours 1
• For children 6 to under 12 years: 1/2 tablet (2 mg) every 4-6 hours, not exceeding 3 tablets in 24 hours 1
• For children under 6 years: oral chlorpheniramine is not recommended 1

Parenteral Dosing for Special Situations (e.g., Anaphylaxis)

When parenteral administration is required in emergency situations such as anaphylaxis management:

• Children over 12 years: 10 mg IM or IV slowly 2, 3
• Children 6-12 years: 5 mg IM or IV slowly 2, 3
• Children 6 months to 6 years: 2.5 mg IM or IV slowly 2, 3
• Children under 6 months: 250 μg/kg IM or IV slowly 2, 3

Pharmacokinetic Considerations

• Chlorpheniramine has a mean serum half-life of approximately 13.1 hours in children 6-16 years 4
• The volume of distribution averages 7.0 L/kg, suggesting significant tissue binding 4
• Therapeutic serum concentrations range from 2.3-12.1 ng/mL for symptom suppression 4
• Pharmacokinetic studies indicate that age-/weight-based dosing achieves similar maximum concentration (Cmax) and area under the curve (AUC) across pediatric age groups 5

Important Clinical Considerations

• Chlorpheniramine should be used as adjunctive therapy after epinephrine in anaphylaxis management, never as first-line treatment 3
• Sedation is the most common adverse effect and appears to be more prevalent in children 2-5 years old 5
• First-generation antihistamines like chlorpheniramine can cause reduced concentration and performance 3
• Due to first-pass metabolism, only 25-45% of orally administered chlorpheniramine reaches systemic circulation 6

Precautions

• Use with caution in children with asthma, as antihistamines can potentially thicken bronchial secretions 7
• Monitor for excessive sedation, especially in younger children 5
• Consider the sedating effects when administering during daytime, particularly for school-aged children 3
• Avoid use in children with severe renal impairment 3

Alternative Routes of Administration

• While oral administration is most common, intravenous and intramuscular routes are documented for specific clinical scenarios such as anaphylaxis 7, 2
• Topical formulations may be beneficial for localized allergic reactions, though these are not commonly available in standard pediatric practice 6