What is the recommended dose of chlorpheniramine (antihistamine) in pediatric neonates?

Chlorpheniramine Dosing in Neonates

Chlorpheniramine is not recommended for use in neonates, and there are no established dosing guidelines specifically for this age group. 1

Safety Concerns and Recommendations

• The American Academy of Pediatrics does not include specific dosing recommendations for antihistamines like chlorpheniramine in neonates 1
• For allergic reactions in neonates requiring intervention, consultation with a pediatric allergist or emergency medicine specialist is strongly recommended before administering any antihistamine 1
• In cases of severe allergic reactions in neonates, epinephrine remains the first-line treatment (0.01-0.03 mg/kg of 1:10,000 solution), not antihistamines 1

Alternative Approaches for Older Pediatric Patients

• For older pediatric patients (not neonates), diphenhydramine is more commonly used with a recommended dose of 1-2 mg/kg per dose (maximum 50 mg) 2
• For infants and young children, the American Academy of Pediatrics recommends using the lower end of the dosing range (1 mg/kg) for diphenhydramine 2

Pharmacokinetic Considerations

• Chlorpheniramine has a long half-life (approximately 13-15 hours) even in older children, which could be problematic in neonates whose metabolic systems are immature 3, 4
• The volume of distribution for chlorpheniramine is large (7.0 ± 2.8 L/kg in children 6-16 years), suggesting significant tissue binding that could lead to accumulation in neonates 4

Important Precautions

• Antihistamines like chlorpheniramine can cause significant adverse effects in neonates, including:
  • Sedation and respiratory suppression 1
  • Hypotension 1
  • Paradoxical excitement or agitation 1
  • Potential for seizures with rapid administration 1

Clinical Decision Making

• If an antihistamine must be used in a neonate (which should be avoided if possible):
  • Consult with a pediatric allergist or emergency medicine specialist first 1
  • Consider that monitoring for respiratory depression, hypotension, and neurological effects will be essential 1
  • Remember that antihistamines should be considered second-line therapy to epinephrine in anaphylaxis 2