Famotidine Dosing for a 1-Year-Old Child Weighing 21 Pounds
The recommended dose of Pepcid (famotidine) for a 1-year-old child weighing 21 pounds (9.5 kg) is 0.5 mg/kg/dose given twice daily, which equals approximately 5 mg twice daily.
Dosage Calculation
Famotidine dosing for children under 40 kg requires special consideration as the standard adult tablets (20 mg and 40 mg) exceed the appropriate pediatric dose for this weight range 1.
For a child weighing 21 pounds (9.5 kg):
- The appropriate weight-based dose is 0.5 mg/kg/dose
- Total daily dose: 0.5 mg/kg × 9.5 kg × 2 times per day = approximately 9.5 mg per day
- This equals approximately 5 mg per dose, given twice daily
Administration Considerations
- Formulation: The FDA label specifically states that 20 mg and 40 mg tablets are not recommended for children weighing less than 40 kg 1
- Alternative formulation: Use a pediatric-appropriate formulation such as oral suspension for accurate dosing
- Timing: Administer doses approximately 12 hours apart for consistent acid suppression
Indications and Duration
For pediatric patients, famotidine may be used for:
- Gastroesophageal reflux disease (GERD)
- Erosive esophagitis
- Peptic ulcer disease
Duration of therapy should be based on the specific indication:
- For symptomatic non-erosive GERD: Up to 6 weeks
- For erosive esophagitis: Up to 12 weeks
- For active duodenal or gastric ulcer: Up to 8 weeks
Important Considerations
- Renal function: If the child has any renal impairment, dose adjustment would be necessary 1
- Monitoring: Monitor for improvement in symptoms within 1-2 weeks
- Side effects: Watch for headache, diarrhea, constipation, or abdominal discomfort
Cautions and Contraindications
- Famotidine is excreted primarily by the kidneys, so renal function should be considered when dosing
- CNS adverse reactions have been reported, though these are more common in elderly patients with renal impairment 1
- Avoid concurrent use with medications that may interact with famotidine
Developmental Pharmacokinetic Considerations
Children older than 1 year of age often require weight-adjusted dosing that differs from adults due to developmental differences in drug metabolism and elimination 2. For famotidine specifically, weight-based dosing is essential to achieve therapeutic levels while avoiding excessive exposure.
Remember that physiological differences between children and adults result in age-related differences in pharmacokinetics and drug effects, making proper weight-based dosing crucial for safety and efficacy in pediatric patients 2.