Ondansetron (Zofran®) for Dogs and Cats

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Overview of Ondansetron for Canines and Felines

  •  Ondansetron, commonly known by the brand name Zofran®, is used in dogs and cats to treat a variety of conditions with the most common being vomiting. It can also be used to treat sleep-apnea and pruritus (itching) in some pets. 
  • Ondansetron is a drug that selectively inhibits serotonin 5HT3 receptors. 5HT3 receptors are located on vagal nerve terminals, enteric neurons in the GI tract, and centrally in the brain in a region called the chemoreceptor trigger zone.
  • Ondansetron is used as an antiemetic, particularly to prevent severe vomiting associated with cancer chemotherapy or radiotherapy.
  • Following oral administration, ondansetron is well absorbed.
  • Ondansetron has does not stimulate gastric or intestinal peristalsis, and has little effect on blood pressure, heart rate or rhythm.
  • Ondansetron is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.
  • This drug is not approved for use in animals by the Food and Drug Administration but it is prescribed legally by veterinarians as an extra-label drug.
  • Brand Names and Other Names of Ondansetron

  • This drug is registered for use in humans only.
  • Human formulations: Zofran® (Glaxo Smith Kline).
  • Veterinary formulations: None
  • Uses of Ondansetron for Dogs and Cats

  • As an antiemetic for treatment of severe vomiting resulting from cancer therapy or poisoning
  • Treatment of sleep-apnea in bulldogs
  • Treatment of pruritus occurring secondary to spinal or epidural opioids
  • Precautions and Side Effects

  • Ondansetron should not be used in animals with known hypersensitivity or allergy to the drug.
  • Drug Interactions

    Ondansetron may interact with other medications. Consult with your veterinarian to determine if other drugs your pet is receiving could interact with ondansetron. Possible interactions may include:

  • Injectable ondansetron should only be mixed with solutions with which it has been shown to be compatible. It should not be mixed with any alkaline solutions or a precipitate may form.
  • Rifampin decreases plasma levels of ondansetron and will thus reduce its efficacy.
  • How Ondansetron is Supplied

  • Ondansetron is available in 4 mg, 8 mg, 24 mg tablets.
  • Ondansetron 4 mg/5 mL oral solution is also available.
  • The injectable form of ondansetron may vary. Some injectable forms include a 2 mg/mL concentration in a 20 mL multidose vials and a 32 mg/50 mL concentration.
  • Dosing Information of Ondansetron for Dogs and Cats

  • Medication should never be administered without first consulting your veterinarian.
  • Doses of may vary widely depending on the reason for prescribing.
  • The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects.
  • In dogs, the usual dose is 0.05 to 0.5 mg per pound (0.1 to 1.0 mg/kg) orally every 12 to 24 hours. The intravenous dose is 0.05 to 0.1 mg per pound (0.1 to 0.2 mg/kg).
  • In cats, the usual dose is 0.11 mg per pound (0.22 mg/kg) every 8 to 12 hours.
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    Gastroenterology & Digestive diseases
    Dermatology & Integumentary diseases
    Respiratory & Thoracic diseases