What is the appropriate dosage of brompheniramine for a 6-year-old child?

Brompheniramine Dosing for a 6-Year-Old Child

For a 6-year-old child, administer brompheniramine 5 mL (1 teaspoonful) every 4 hours, not exceeding 6 doses in 24 hours, as specified by FDA labeling. 1

FDA-Approved Dosing by Age

The FDA drug label provides clear age-based dosing for brompheniramine oral solution 1:

• Children 6 to under 12 years of age: 5 mL (1 teaspoonful) every 4 hours 1
• Children 2 to under 6 years of age: 2.5 mL (½ teaspoonful) every 4 hours 1
• Maximum: Do not exceed 6 doses during a 24-hour period 1

Pharmacokinetic Considerations in Children

Brompheniramine demonstrates favorable pharmacokinetics in pediatric patients:

• Onset of action: Significant histamine blockade begins at 0.5 hours and persists for 30 hours after a single 4 mg dose 2
• Peak concentration: Occurs at approximately 3.2 hours in children (mean age 9.5 years) 2
• Duration of effect: Maximum wheal inhibition occurs at 12 hours (52%) and maximum flare inhibition at 6 hours (72%) 2
• Half-life: Terminal elimination half-life is 12.4 hours in children 2

Recent pharmacokinetic studies confirm that age/weight-based dosing achieves similar drug exposure across pediatric age groups, with no clinically significant age-related differences after allometric scaling 3

Critical Safety Considerations

Sedation Risk

• Sedation is the most common adverse effect and appears more prevalent in children aged 2-5 years compared to older children 3
• Performance impairment occurs from 1.5 to 3.0 hours after administration of immediate-release brompheniramine 4 mg 4
• Monitor for excessive drowsiness, especially during the first few hours after administration 3

Asthma Warning

• A subset of asthmatic children may experience bronchospasm with brompheniramine 5
• If the child has asthma and reports chest tightness or wheezing after taking brompheniramine, discontinue immediately 5
• Premedication with theophylline can prevent pulmonary function decline in susceptible children, though this is rarely practical in outpatient settings 5

Anticholinergic Effects

• Brompheniramine has anticholinergic properties approximately 16-19 times less potent than atropine 6
• Monitor for dry mouth, urinary retention, and constipation, though these are less common in children 6

Clinical Context and Alternatives

When to Consider Alternatives

The American Academy of Otolaryngology-Head and Neck Surgery recommends second-generation antihistamines (cetirizine or loratadine) as first-line therapy for allergic rhinitis in children 7, 8:

• Cetirizine: 5-10 mg once daily for children aged 6-12 years 7
• Loratadine: 5 mg once daily for children aged 2-5 years; 10 mg once daily for children ≥6 years 7

Second-generation antihistamines offer advantages over brompheniramine 8:

• Less sedation
• Once-daily dosing improves compliance
• Superior safety profile with very low rates of serious adverse events 8

When Brompheniramine May Be Appropriate

Brompheniramine remains a reasonable option when 2:

• Second-generation antihistamines have failed or are not tolerated
• Cost is a significant barrier (brompheniramine is typically less expensive)
• Rapid onset of action is needed (begins working within 30 minutes) 2

Common Pitfalls to Avoid

• Do not use combination cough/cold products containing brompheniramine in children under 6 years due to overdose risk 8
• Do not exceed the maximum of 6 doses in 24 hours (30 mL total daily dose for a 6-year-old) 1
• Avoid evening doses if sedation interferes with school or activities the following day 4
• Do not use to induce sleep as this is explicitly contraindicated per FDA labeling 8