What concentration of famotidine oral suspension is appropriate for a child weighing 106 lb (≈48 kg)?

Famotidine Concentration for a 106-Pound Child

For a child weighing 106 pounds (48 kg), the appropriate famotidine oral suspension concentration is 40 mg/mL cherry-banana-mint–flavored oral suspension, administered at a total daily dose of 48 mg divided into two doses of 24 mg each (twice daily). 1

Dosing Calculation

• Standard pediatric dosing for famotidine is 1 mg/kg/day, divided into 2 doses 1
• For a 48 kg child: 48 kg × 1 mg/kg/day = 48 mg total daily dose
• This translates to 24 mg twice daily (every 12 hours) 1
• The maximum adult dose is 40 mg twice daily, which this child does not exceed 1

Formulation Details

• Famotidine oral suspension is available as a cherry-banana-mint–flavored formulation specifically designed for pediatric use 1
• The FDA-approved age range for this formulation is 1 to 16 years, which includes this patient 1
• This child at 48 kg falls well within the weight range where pediatric weight-based dosing applies 1

Clinical Evidence Supporting This Dose

• Pharmacokinetic studies demonstrate that children over 1 year of age have similar famotidine disposition to adults, supporting the 1 mg/kg/day dosing regimen 2
• Research in children with gastroduodenal ulcers showed that 0.5 mg/kg twice daily (equivalent to 1 mg/kg/day total) was effective and well-tolerated, with all ulcers healing within 8 weeks 3
• Studies in severely handicapped children with reflux esophagitis used 1-2 mg/kg/day divided into 2-3 doses, with marked to moderate effectiveness in 70% of cases 4

Administration Schedule

• Administer 24 mg twice daily, approximately 12 hours apart 1, 3
• The twice-daily dosing schedule is supported by famotidine's elimination half-life of approximately 2.3 hours in children, with acid-inhibiting effects lasting approximately 6 hours 1
• Dosing can be given without regard to meals, though consistency in timing relative to meals may help with adherence 3

Important Clinical Considerations

• This child weighs more than 40 kg but is still within the pediatric age range (1-16 years), so weight-based pediatric dosing rather than fixed adult dosing is appropriate 1
• Famotidine has advantages over other H2-receptor antagonists including greater potency, longer elimination half-life, and lack of cytochrome P450 interactions (unlike cimetidine) 2
• Tachyphylaxis can develop within 6 weeks of H2-receptor antagonist therapy, which may limit long-term effectiveness 1
• No dose adjustment is needed for this weight unless there is renal impairment, as famotidine is primarily renally eliminated 5

Safety Profile

• Famotidine has been studied in over 150 children with excellent safety profiles 2
• No significant side effects were observed in pediatric studies, though transient mild liver enzyme elevations occurred in some patients but were not attributed to the drug 4
• Famotidine does not cause gynecomastia or liver disease (unlike cimetidine), making it a preferred H2-receptor antagonist in pediatric populations 1

Monitoring Recommendations

• Assess symptom improvement within 1-2 weeks of initiating therapy 4
• For erosive esophagitis or ulcer disease, treatment duration is typically 8 weeks with endoscopic reassessment if symptoms persist 3
• Consider switching to a proton pump inhibitor if inadequate response after 2-3 weeks, as PPIs have superior efficacy for erosive esophagitis compared to H2-receptor antagonists 1