Chlorpheniramine Dosing for an 11-Year-Old Child
For an 11-year-old child, the recommended dose of chlorpheniramine is 5 mg administered intramuscularly or intravenously slowly, or one-half tablet (2 mg) orally every 4 to 6 hours, not exceeding 3 tablets (6 mg) in 24 hours. 1, 2
Route-Specific Dosing
Parenteral Administration (IM or IV)
- Children aged 6 to 12 years: 5 mg administered intramuscularly or intravenously slowly 1
- This dosing is specifically outlined in anesthesia guidelines for managing suspected anaphylactic reactions 1
Oral Administration
- Children aged 6 to under 12 years: 2 mg (one-half tablet) every 4 to 6 hours 2
- Maximum daily dose: 6 mg (3 tablets) in 24 hours 2
- This represents the FDA-approved dosing for over-the-counter chlorpheniramine products 2
Clinical Context and Pharmacokinetics
The dosing recommendations are supported by pharmacokinetic data demonstrating that:
- Children aged 6-16 years have a mean elimination half-life of approximately 13 hours 3, 4
- Therapeutic serum concentrations range from 2.3 to 12.1 ng/ml for symptom suppression 3
- The drug has a large volume of distribution (7.0 L/kg), indicating significant tissue binding 3
Important Safety Considerations
Age Restrictions
- Chlorpheniramine should not be used in children under 6 years of age 2
- The British Journal of Dermatology confirms that currently licensed antihistamines are not contraindicated in children 12 years and older 5
Common Pitfalls to Avoid
- Avoid using chlorpheniramine for common cold symptoms in children, as efficacy has not been established for upper respiratory infections 6
- Use only for clear allergic indications such as allergic rhinitis or urticaria as diagnosed by a healthcare professional 6
- Be aware that combination products containing opioids (such as hydrocodone/chlorpheniramine) are contraindicated in all patients under 18 years due to unfavorable benefit-risk profile 7
Renal Impairment Considerations
While the evidence primarily addresses hydroxyzine rather than chlorpheniramine specifically, antihistamine dosing generally requires adjustment in renal impairment, with dose reductions of 50% recommended for moderate to severe renal dysfunction 5