Famotidine

What is this medication for?

• Gastric/duodenal ulcers, gastritis, esophagitis (adjunct)

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

• Give with food for best absorption.
• Always give into a vein doses to cats slowly (over 5 minutes) — rapid into a vein push has anecdotally caused hemolysis.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• CNS effects (High-dose, human data)

Worth a phone call to your veterinarian

• Generally well tolerated (Adverse effects mainly with decreased renal clearance)
• Intravascular hemolysis (rapid into a vein) (Rare, anecdotal)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Trouble breathing, collapse, seizures, severe vomiting or diarrhea, facial swelling, or pale gums

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: H2-blocker hypersensitivity
• has or has had: Cardiac disease (mild negative inotrope/arrhythmogenic potential), significant hepatic/renal impairment

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Ketoconazole, itraconazole, iron
  • —

Storage and handling

Room temperature, protect from light. Compounded cherry-syrup formulation stable 14 days. Diluted into a vein solution stable 48h at room temp.

Good to know

• Efficacy evidence is genuinely mixed — some studies show benefit at 1 mg/kg, others show no difference from placebo for raising gastric pH in dogs; omeprazole is more consistently effective and now often preferred for significant stomach/intestinal ulceration.
• Give with food for best absorption.
• Always give into a vein doses to cats slowly (over 5 minutes) — rapid into a vein push has anecdotally caused hemolysis.