Famotidine

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Administration

  • Type: Histamine (H2) blocker
  • Dosage Forms: 10, 20, and 40 PO; 40/5 mL suspension
  • Routes of Administration: PO, IV
  • Common Trade Names: Pepcid, Pepcid AC

Adult Dosing

Active duodenal ulcer
  • 40mg PO qhs x4-6 weeks
  • Alt dosing: 20mg PO BID or 20mg IV q12 hr
Maintenance duodenal ulcer
  • 20mg PO qhs
Gastric ulcer
  • 40mg PO qhs
  • Alt dosing: 20mg IV q12 hr
GERD
  • 20-40mg PO BID x12 weeks
  • Alt dosing: 20mg IV q12 hr
Zollinger-Ellison syndrome
  • 20-60mg PO q6 hr
  • Alt dosing: 20mg IV q12 hr
  • Max: 160mg PO q6 hr
intractable ulcer
  • 20mg IV q12 hr
H. pylori infection
  • 20mg PO BID x 10-28 days
  • Use in combination with other medications for eradication

Pediatric Dosing

PUD
  • 1-16 years old
    • 0.5-1mg/kd/day PO daily-bid
    • Start at 0.5mg/kg/day daily-bid
    • Alt dosing: 0.5-1mg/kg/day IV bid
    • Max 40mg/day
GERD
  • <3 mo
    • 0.5mg/kg/day PO daily
  • 3-12 mo
    • 1mg/kg/day PO bid
  • 1-16 yo
    • 1-2mg/kg/day PO bid
    • Start 1mg/kg/day bid
    • Alt dosing: 0.5-1mg/kg/day IV bid
    • Max 40mg/day

Special Populations

Renal Dosing

  • Adult: CrCl<50: decrease dose by 50% or give q 36-48 hr; If on dialysis give after dialysis
  • Pediatric: CrCl 10-50: decrease dose 50% or give q24 hr, CrCl<10: give q36-48 hr

Hepatic Dosing

  • Adult: Not defined
  • Pediatric:Not defined

Contraindications

  • Allergy to class/drug
  • Caution in renal impairment

Adverse Reactions

Serious

Common

  • headache
  • dizziness
  • constipation
  • diarrhea
  • taste changes
  • vitamin B12 deficiency

Pharmacology

  • Half-life: 2.5-3.5 hr; >20 hr with CrCl<10
  • Metabolism: minimally liver/CYP450
  • Excretion: urine

Mechanism of Action

  • Selective histamine H2 blocker

Comments

See Also

References