The Side Effects of Amitriptyline in Cats

Although it is one of the common drugs prescribed for nervous or anxious cats, Amitriptyline should be administered carefully. This drug is an anti-anxiety medication and is useful for dealing with feline separation anxiety, excessive grooming, nervousness, spraying and inappropriate elimination. It is a powerful antihistamine, and blocks the parasympathetic nervous system along with other nervous system functions.


  • Follow the dosage recommended and in case you miss a dose, skip it entirely.
  • Do not overdose at a time. Amitriptyline can be highly toxic in large doses, which can lead to death.
  • Since Amitriptyline is bitter, it may be difficult to administer in a tablet form.
  • You may get a liquid form or a topical gel which may be easier to dispense.

Amitriptyline has shown to have many side effects, ranging from short term changes to serious ramifications. A thorough knowledge of these can help you get the best results for your cat and avoid medical emergencies.

Side Effects

  • Excessive salivation
  • Drowsiness
  • Dry mouth (displayed by licking of lips)
  • Urinary retention
  • Constipation
  • Marked change in appetite
  • Weight gain
  • Dishevelled fur
  • Confusion and disorientation
  • Abnormal heart rhythm
  • Easily bruised skin
  • Irritated skin due to the gel
  • Low blood pressure
  • Allergic reactions
  • Facial puffiness
  • Rapid onset of diarrhea
  • Convulsions
  • Discoloured gums
  • Limbs feel cold
  • Coma


  • Do not administer Amitriptyline if your cat is allergic to drugs that belong to the class of tricyclic antidepressants.
  • Since there is a high chance of your cat developing a cardiac disturbance, an EKG should be done before starting this medication.
  • If your cat has a liver impairment or is diabetic, avoid the use of Amitriptyline. If your cat is going to be on this drug for a long term, it's better to conduct periodic blood tests to ensure that her liver is healthy.
  • Do not use this medication if your cat is pregnant or lactating.

Amitriptyline in Combination

It is better to avoid the use of Amitriptyline along with other psychotropic substances.

  • Interactions may occur if Amitriptyline is administered with vitamins, appetite stimulants and supplements.
  • It can cause reactions when used with sympathomimetic amines such as ephedrine, phenylpropanolamine (Proin, Cystolamine), methimazole, or other antithyroid drugs and monoamine oxidase inhibitors, such as selegiline.
  • It may also have a converse effect when used with amitraz, which is found in some flea collars and in Mitabin, which is a medication for mange.
  • When used in conjunction with the wrong drugs, Amitriptyline may alter blood glucose levels or cause a dangerous drop in the white blood cell count.
  • Amitriptyline is a prescription drug and can only be obtained from a veterinarian. Although it's primarily a drug meant for human use, it can be prescribed legally by a vet as an extra-label drug. Having an understanding of the drug, its uses and its side effects, can help you make an informed decision and guarantee a healthy, happy and content cat.