Diphenhydramine Dosing for a 12.9 kg Child
The recommended dose of diphenhydramine (Benadryl) for a 12.9 kg child is 12.9 mg (1 mg/kg) every 6 hours as needed, not to exceed 5 mg/kg/day.
Dosing Guidelines
While the provided evidence focuses primarily on influenza treatments rather than diphenhydramine specifically, we can apply standard pediatric dosing principles for diphenhydramine:
- For children: 1-1.25 mg/kg/dose every 6 hours
- Maximum: 5 mg/kg/day or 300 mg/day (whichever is less)
For a 12.9 kg child:
- Single dose: 12.9-16.1 mg (using 1-1.25 mg/kg)
- Practically, this would be rounded to 12.5-15 mg per dose
- Maximum daily dose: 64.5 mg (using 5 mg/kg/day)
Administration Options
Diphenhydramine is available in several formulations:
- Liquid: 12.5 mg/5 mL
- Chewable tablets: 12.5 mg
- Capsules/tablets: 25 mg
For a 12.9 kg child, the most appropriate formulation would be:
- Liquid: 5 mL (12.5 mg) per dose
- Chewable tablet: 1 tablet (12.5 mg) per dose
Important Considerations
- Safety concerns: First-generation antihistamines like diphenhydramine have significant sedative effects and potential for toxicity 1, 2
- Sedation risk: Diphenhydramine causes significant sedation which may affect the child's activities and alertness
- Monitoring: Watch for excessive drowsiness, paradoxical excitation, or dry mouth
- Duration: Limit use to short-term treatment (2-3 days) when possible
Alternative Options
Consider second-generation (non-sedating) antihistamines for children when appropriate, as they:
Cautions
- Avoid in children under 2 years except under medical supervision
- Use with caution in children with asthma, glaucoma, or urinary retention
- Be aware of potential for misuse or overdose 4
- Avoid concomitant use with other sedating medications
For accurate dosing, always measure liquid formulations with a proper measuring device (syringe or medication cup), not household spoons.