Diphenoxylate (Logen®, Lomotil®, Lonox®) for Dogs and Cats


Overview of Diphenoxylate for Dogs and Cats

  • Diphenoxylate belongs to a class of drugs known as opiate agonists (morphine derivative). Diphenoxylate, also known as Logen®, Lomotil®, and Lonox®, is primarily used to treat diarrhea and colitis in dogs and cats. It also has anti-coughing properties. 
  • Diphenoxylate slows the gastrointestinal tract, decreases intestinal secretions and enhances absorption of liquids.
  • Diphenoxylate 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 of Diphenoxylate 

  • This drug is registered for use in humans only.
  • Human formulations: Logen® (Goldline), Lomotil® (Searle), Lonox® (Geneva) and various generic brands.
  • Veterinary formulations: None
  • Uses of Diphenoxylate for Dogs and Cats

  • Diphenoxylate is primarily used to treat diarrhea and colitis.
  • Precautions and Side Effects

  • While generally safe and effective when prescribed by a veterinarian, diphenoxylate can cause side effects in some animals.
  • Diphenoxylate should not be used in animals with known hypersensitivity or allergy to the drug. Not recommended for use in young kittens and should be used with care in small dogs. 
  • Diphenoxylate should be avoided in animals with an overactive thyroid, kidney impairment, head trauma, colic,lung disease or liver disease.
  • Diphenoxylate may interact with other medications. Consult with your veterinarian to determine if other drugs your pet is receiving could interact with diphenoxylate. Such drugs include certain antihistamines, tranquilizers, barbiturates and monoamine oxidase inhibitors.
  • The most common adverse effects are constipation and sedation.
  • Diphenoxylate’s use in cats is controversial and should be avoided.
  • How Diphenoxylate Is Supplied

  • Diphenoxylate is available in 2.5 mg tablets or liquid (combined with atropine).
  • Dosing Information of Diphenoxylate for Dogs and Cats

  • Medication should never be administered without first consulting your veterinarian.
  • Liquid diphenoxylate is dosed at 2 to 15 ml four times daily for diarrhea.
  • In dogs, diphenoxylate is dosed at 0.05 to 0.1 mg per pound (0.1 to 0.2 mg/kg) two to three times daily. For coughing, diphenoxylate is dosed at 0.1 mg to 0.2 mg per pound (0.2 to 0.4 mg/kg) every 8 to 12 hours. 
  • In cats, diphenoxylate is dosed at 0.025 to 0.05 mg per pound (0.05 to 0.1 mg/kg) twice daily. This is controversial and many veterinarians avoid using diphenoxylate in cats, especially young kittens.
  • The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your pet feels better, the entire treatment plan should be completed to prevent relapse or prevent the development of resistance.
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    Gastroenterology & Digestive diseases


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