Diphenhydramine (Benadryl) Safety in Infants
Diphenhydramine (Benadryl) should not be used in infants under 6 years of age due to significant safety concerns and FDA contraindications. 1
Safety Guidelines for Diphenhydramine in Children
The FDA drug label for diphenhydramine explicitly states:
- Adults and children over 12 years: 10-20 mL (25-50 mg) every 4-6 hours
- Children 6 to under 12 years: 10 mL (25 mg) every 4-6 hours
- Children under 6 years of age: Do not use 1
Risks of Diphenhydramine in Infants
Diphenhydramine poses several serious risks to infants:
- Fatal toxicity: Multiple case reports document infant deaths from diphenhydramine at blood levels lower than those causing fatality in adults 2
- Paradoxical excitation: While sedating in adults, diphenhydramine can cause central nervous system stimulation in children, ranging from agitation to seizures 2
- Respiratory depression: May cause significant respiratory suppression, especially when combined with other medications 3
- Narrow therapeutic window: The difference between therapeutic and toxic doses is small in infants 4
Alternative Approaches for Infants
For allergic conditions in infants, consult a pediatrician for appropriate management. The American Academy of Pediatrics recommends:
- Second-generation antihistamines are preferred over first-generation antihistamines (like diphenhydramine) when antihistamines are necessary 5
- For severe allergic reactions, epinephrine is the first-line treatment, with appropriate pediatric dosing 5
Toxic Dose Thresholds
If accidental ingestion occurs:
- Ingestions of ≥7.5 mg/kg in children under 6 years require immediate emergency department evaluation 6, 4
- Even at doses below this threshold, infants are at higher risk for adverse effects 2
Warning Signs of Toxicity
Seek immediate medical attention if any of these symptoms develop after diphenhydramine exposure:
- Changes in behavior beyond mild drowsiness
- Agitation or paradoxical excitation
- Inconsolable crying
- Hallucinations
- Abnormal muscle movements
- Seizures
- Respiratory depression 6
Key Cautions
- Never use diphenhydramine to sedate infants: Cases of intentional administration to induce sleep have resulted in infant deaths 2
- Topical formulations can also be dangerous: Fatal diphenhydramine toxicity has occurred from excessive topical application in toddlers 7
- Keep all diphenhydramine products out of reach of children: Accidental ingestion can be life-threatening 6
The evidence clearly demonstrates that diphenhydramine should not be administered to infants under any circumstances without explicit physician direction in a controlled medical setting.