What is the recommended dose of Phenergan (promethazine) per kilogram for pediatric patients?

Recommended Dosage of Promethazine (Phenergan) for Pediatric Patients

The recommended dose of promethazine (Phenergan) for pediatric patients is 1-2 mg/kg per dose, with a maximum initial dosage of 50 mg. 1

Dosing Guidelines

Promethazine can be administered through different routes:

• IV/IM route: 1-2 mg/kg per dose (maximum initial dose: 50 mg)
• Oral route: Similar dosing principles apply, though the IV/IM route is more commonly referenced in emergency guidelines

Indications and Considerations

Promethazine is primarily used in pediatric patients for:

• Acute hypersensitivity reactions
• Management of dystonic reactions
• Antiemetic effects for nausea and vomiting

Important Safety Considerations

Adverse Effects

• Sedation and respiratory suppression: Particularly when used with other sedative agents
• Hypotension: Monitor blood pressure during administration
• Seizures: Rapid IV administration may precipitate seizures
• Paradoxical excitement or agitation: Can occur at any dose

Age Restrictions

• Not recommended for children under 2 years: Risk of respiratory depression is significantly higher in this age group
• Use with extreme caution in young children: Increased risk of adverse effects

Administration Precautions

• Slow IV administration: Rapid administration increases risk of adverse effects
• Careful monitoring: Observe for respiratory depression, especially when combined with other sedatives

Special Populations

For patients with:

• Neurological abnormalities: Higher risk of complications, use with extreme caution
• Head injuries: May require dose adjustment and closer monitoring
• Abnormal mental status: Associated with increased risk of respiratory depression

Alternative Routes

When IV/IM routes are not feasible, alternative formulations may be considered:

• Transdermal preparations have been used in case reports for managing nausea and vomiting in pediatric patients who cannot tolerate oral medications 2

Algorithm for Safe Use

1. Confirm appropriate indication for promethazine use
2. Calculate weight-based dosing: 1-2 mg/kg (not exceeding 50 mg)
3. Assess patient risk factors: Age, neurological status, concurrent medications
4. Select appropriate administration route
5. Monitor closely for respiratory depression, hypotension, and paradoxical reactions
6. Have resuscitation equipment readily available

Remember that complications are increased in patients with acute or underlying neurological abnormalities 3, and careful patient selection is essential for safe use of this medication.