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Ranitidine

Prescription
Histamine H2-receptor antagonist
Last reviewed 19 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
3 available
Interactions
1 documented
Formulations
3

Mechanism of action

Competitively blocks H2 receptors on parietal cells, reducing acid secretion; also has prokinetic activity by inhibiting acetylcholinesterase

At a glance

Class
Histamine H2-receptor antagonist
Schedule
Prescription
Storage
Store below 25°C, protect from light

Dosing

🐕

Dog

Gastric ulceration / Gastritis / GI motility disorders
Dose
1–2 mg/kg
Route
PO, IV, SC
Frequency
BID to TID
Max dose
150 mg/dose; 450 mg/day
Duration: 5–14 days
🐈

Cat

Gastric ulceration / Uremic gastritis
Dose
1–2.5 mg/kg
Route
PO, IV
Frequency
BID
Max dose
25 mg/dose; 50 mg/day
Duration: 5–14 days
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Formulations

💊

Tablet — 2

Strength
150mg
Available in India
Strength
300mg
Available in India
💉

Injection — 1

Strength
25mg/mL
Available in India

Storage

Store below 25°C, protect from light

Safety

Absolute contraindications — do not use

  • Known hypersensitivity

Use with caution

  • Hepatic impairment
    Dose adjustment needed
  • Concurrent azole antifungals
    Reduced absorption of azoles

Adverse effects

Common
Generally well tolerated
Mild GI upset
Serious
Arrhythmias (rapid IV)
Thrombocytopenia (rare)

Monitoring parameters

GI symptom resolutionHeart rate (with IV use)
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Interactions

Moderate — 1

Ketoconazole
moderate
H2 blockers reduce gastric acid, decreasing ketoconazole absorption by up to 95%
Management: Separate administration by 2+ hours. Consider switching to fluconazole.
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Brands

International

Zantac
GSK

India

Rantac
J.B. Chemicals
Aciloc
Cadila/Zydus

FAQs

Frequently asked questions

›What is Ranitidine?
Ranitidine is a histamine h2-receptor antagonist used in pets. Competitively blocks H2 receptors on parietal cells, reducing acid secretion; also has prokinetic activity by inhibiting acetylcholinesterase
›What is Ranitidine used for in pets?
Ranitidine is used in veterinary medicine for: Gastric ulceration / Gastritis / GI motility disorders; Gastric ulceration / Uremic gastritis.
›What is the Ranitidine dose for dogs?
For dogs, Ranitidine is typically dosed as follows — Gastric ulceration / Gastritis / GI motility disorders: 1–2 mg/kg PO/IV/SC BID to TID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Ranitidine dose for cats?
For cats, Ranitidine is typically dosed as follows — Gastric ulceration / Uremic gastritis: 1–2.5 mg/kg PO/IV BID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What are the side effects of Ranitidine?
Common: Generally well tolerated, Mild GI upset. Serious (call your vet immediately): Arrhythmias (rapid IV), Thrombocytopenia (rare).
›Does Ranitidine need a prescription?
Yes. Ranitidine is a prescription medication and should only be administered under veterinary supervision.
›When should Ranitidine not be used?
Do not use Ranitidine if: Known hypersensitivity.
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

References

References

The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.

Textbooks & handbooks — 5

  • Plumb's Veterinary Drug Handbook
  • Withrow & MacEwen's Small Animal Clinical Oncology
  • Merck Veterinary Manual
  • NRC Nutrient Requirements of Dogs and Cats
  • Veterinary Pharmacology and Therapeutics (Riviere & Papich)

Clinical guidelines & consensus — 4

  • ASPCA Animal Poison Control Center Guidelines
  • AAHA Diabetes Management Guidelines
  • ASPCA Poison Control Guidelines
  • RECOVER CPR Guidelines

Journals & peer-reviewed studies — 2

  • EPIC Study (J Vet Intern Med 2016)
  • JVIM FAT CAT Study

Regulatory & approvals — 1

  • CDSCO Veterinary Drug Approval Registry (1969–2026)

Databases — 1

  • Washington State University VCPL MDR1 Database

Related medicines

Other medicines in the same class (Histamine H2-receptor antagonist).

Famotidine
Rx
Competitively blocks histamine H2 receptors on parietal cells, reducing basal and stimulated gastric acid secretion
dogcat
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