Famotidine

Mechanism :

Famotidine is a competitive inhibitor of histamine H2-receptors. The primary clinically important pharmacologic activity is inhibition of gastric juice secretion. Famotidine reduces the acid and pepsin content, as well as the volume, of basal, nocturnal, and stimulated gastric secretion.

Indication :

Peptic ulcer
GERD
Heartburn

Contraindications :

Hypersensitivity to any component of this medication.

Dosing :

Peptic Ulcer Disease:

1-16 years: 0.5 mg/kg/day once orally at bed time OR 0.25 mg/kg IV every 12 hours; Max: 40 mg/day.

GERD:

Under 3 months: 0.5 mg/kg/day orally once daily upto 8 weeks.

3-12 months: 1 mg/kg/day orally every 12 hours for upto 8 weeks.

1-16 years: 1 mg/kg/day orally in two divided doses; Max: 40 mg/day.

Heartburn:

Under 12 years: Not established.

Above 12 years: 10-20 mg twice daily; may take 15-60 min before eating foods that can cause heartburn.

Adverse Effect :

Headache, dizziness, constipation and diarrhea.

Serious Reactions: Anaphylaxis, Stevens-Johnson syndrome, angioedema, leukopenia, toxic epidermal necrolysis, agranulocytosis, thrombocytopenia, pancytopenia, seizures, arrhythmias, AV block, hepatitis, cholestatic jaundice, interstitial pneumonia, QT prolongation.

Interaction :

Ketoconazole, Triamterene, Delavirdine, Itraconazole, Cefpodoxime, Cyanocobalamin, Indomethacin, Melphalan: Decreased absorption.
Tolazoline: Decreased effect of Tolazoline.

Renal Dose :

Dose in Renal Impairment GFR (mL/min)

20-50	Dose as in normal renal function
10-20	50% of normal dose
<10	20 mg at night (maximum)

Dose in Patients undergoing Renal Replacement Therapies

CAPD	Not dialysed. Dose as in GFR<10 mL/min
HD	Not dialysed. Dose as in GFR<10 mL/min
HDF/High flux	Not dialysed. Dose as in GFR<10 mL/min
CAV/VVHD	Not dialysed. Dose as in GFR=10– 20 mL/min

Hepatic Dose :

Dose adjustment will be needed for pediatric population with hepatic dysfunction because the drug can accumulate, causing toxicity especially in patients with concomitant renal impairment.