Administration of Phenobarbital in a 10 kg Neonate
For a 10 kg neonate requiring phenobarbital, administer as an IV infusion over 10-20 minutes at a rate not exceeding 1 mg/kg per minute rather than as a rapid IV bolus to minimize adverse effects. 1
Dosing Recommendations
Loading Dose:
- Initial dose: 10 mg/kg IV (100 mg total for a 10 kg child)
- Infuse over 10-20 minutes (not to exceed 1 mg/kg/minute)
- For status epilepticus: May increase to 20 mg/kg total if needed
Administration Method:
- Preparation: Dilute in compatible IV solution
- Rate of administration:
- Calculate drip rate: If 1 ml = 20 drops, then for a 100 mg dose in 10 ml solution given over 10 minutes:
- 10 ml ÷ 10 minutes = 1 ml/minute
- 1 ml/minute × 20 drops/ml = 20 drops/minute
Maintenance Dosing:
- 3-4 mg/kg/day (30-40 mg/day for a 10 kg child)
- Divided into 1-2 doses per day
Monitoring Parameters
- Vital signs: Monitor continuously during administration, especially respiratory status
- Therapeutic levels: 15-40 μg/ml
- Seizure control: Assess clinical response
Important Considerations
- Respiratory depression risk: Be prepared to provide respiratory support during administration 1
- Hypotension risk: Monitor blood pressure closely, especially with rapid infusion
- Avoid rapid IV push: Rapid administration increases risk of respiratory depression and hypotension
- Refractory seizures: For non-responders to initial loading dose, additional doses of 5-10 mg/kg may be given until seizures stop or serum concentration reaches 40 μg/ml 2
- Plateau effect: Therapeutic effect plateaus at serum concentrations of 40 μg/ml; consider adding a second anticonvulsant if seizures persist at this level 2
Special Precautions
- Sedation: May cause sedation affecting feeding and respiratory drive
- Half-life: Phenobarbital has a long half-life in neonates (103-141 hours) 3, requiring careful dosing to avoid accumulation
- Drug interactions: Phenobarbital induces hepatic enzymes and may affect metabolism of other medications
Practical Administration Tips
- Use infusion pump for precise control of administration rate
- Calculate the drip rate based on the concentration of the solution and the desired infusion time
- Monitor the IV site for signs of irritation or infiltration
- Have resuscitation equipment readily available
Phenobarbital remains the preferred anticonvulsant for neonatal seizures due to its efficacy and relatively favorable safety profile when administered properly 1, 3.