Selegiline in Dogs: Dosage, Uses and Side Effects

The use of selegiline in dogs has improved cognitive ability in geriatric dogs, as well as increasing their quality of life and longevity.
Selegiline in Dogs: Dosage, Uses and Side Effects
Cesar Paul Gonzalez Gonzalez

Written and verified by the biologist Cesar Paul Gonzalez Gonzalez.

Last update: 21 December, 2022

Selegiline in dogs and humans is used to control the levels of several neurotransmitters. Thanks to this, it has several benefits against mental illnesses, such as Parkinson’s disease (in humans) and geriatric cognitive dysfunction (in dogs).

This drug has a great latent potential to improve the quality of life of older dogs. In addition, it’s characterized by very few side effects, which helps to avoid unpleasant experiences for the pet. Continue reading and learn more about selegiline for dogs.

What is selegiline?

Selegiline is a drug that belongs to the phenylethylamine class, so its chemical structure somewhat resembles that of the neurotransmitter amines. Thanks to this, it’s able to bind to monoamine oxidases type B (MAO-B), which are enzymes in charge of oxidizing and degrading serotonin, noradrenaline, and dopamine.

What is its mechanism of action?

At low doses, selegiline binds to monoamine oxidases type B irreversibly. This means that they prevent them from destroying and oxidizing neurotransmitters, so the amount of dopamine, noradrenaline and serotonin increases. Consequently, there are changes in the cerebral cortex that have neurostimulatory and neuroprotective effects.

Drug presentations

Selegiline usually comes in tablet or capsule form, but there are also transdermal patches and liquid solutions. Depending on the need of the canine patient, the veterinarian will recommend the most appropriate format for each case.

How does selegiline help dogs?

Selegiline in dogs is prescribed to treat mainly cognitive dysfunction syndrome in geriatric patients. This condition appears as a neurodegenerative problem that worsens with age, which closely resembles Alzheimer’s disease.

Simply put, cognitive dysfunction syndrome in geriatric dogs diminishes and atrophies various parts of the brain. As a result, pets begin to exhibit behavioral problems that worsen as they get older. Although there’s no cure as such, selegiline is one of the first drugs to be approved to reduce its progression.

In addition, some studies indicate that selegiline is also suitable for treating canine hyperadrenocorticism of pituitary origin. However, it only works well in cases where excessive ACTH hormone secretion is linked to dopamine deficiency, otherwise it has no positive effect.

A sleeping dog.

Appropriate dosage

The recommended daily dose of selegiline for dogs is usually between 0.5 and 1 milligram per kilogram of body weight. However, veterinarians usually start the medication with lower doses and increase them as treatment progresses. In fact, it’s possible to increase the frequency with which it’s taken, but only if no improvement has been seen in the first few days of treatment.

Typically, administration of this drug should be done once a day and in the mornings. This helps dogs with circadian cycle disorders to begin to regulate their sleep. However, it’s best to follow the instructions of the animal health professional, as each case is different and the same instructions aren’t always needed.

Side effects

One of the benefits of selegiline is that it has few or no side effects in dogs. However, it is possible for some to occur, and even become quite serious. The following effects are the most well known:

  • Vomiting
  • Diarrhea
  • Disorientation
  • Confusion
  • Aggression
  • Repetitive movements
  • Tremors throughout the body
  • A loss of appetite
  • Severe pain (a sign of risk)

Should any of the side effects appear, it’s best to discontinue the medication and take the pet for veterinary consultation. The effects of selegiline will stop in about 24 hours, although in some dogs with kidney or liver problems it may last longer.

A dog resting.


Selegiline shouldn’t be administered to dogs taking meperidine or other opioid drugs. Likewise, its use with antidepressants or selective serotonin reuptake inhibitors (SSRIs) isn’t recommended.

It’s important that, before starting selegiline treatment, all medications taken by the dog should be discussed with the veterinarian. This will help the vet to decide if this drug is the most appropriate for your case or opt for another one. Remember that your pet’s life is at risk, so never hide this information.

Also, keep in mind that the veterinarian is the only one who can prescribe and supervise the treatment of dogs with selegiline. Diagnosis is essential in order to know your pet’s health status and the suitability of the drug. Failure to do so could worsen their condition. So, avoid self-medicating your pet and if you have any questions, consult a professional.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Regaño Otal, L., & Loste Montoya, A. (2019) Actualización del hiperadrenocorticismo canino. (Trabajo de fin de grado, Universidad Zaragoza)
  • Ginel, P. & Lucena, R. (2002) Interés de la selegilina en el tratamiento del hiperadrenocorticismo canino de origen hipofisario. Clin Vet Pequeños Anim, 22(1), 27-31.
  • González-Martínez, Á., Rosado, B., García-Belenguer, S., & Suárez, M. (2012). Síndrome de disfunción cognitiva en el perro geriátrico. Clínica veterinaria de pequeños animales, 32(3), 0159-167.
  • Gallego, D., Figueroa, J., & Orozco, C. (2010). Síndrome de disfunción cognitiva de perros geriátrico. Revista MVZ Córdoba, 15(3).
  • Campbell, S., Trettien, A., & Kozan, B. (2001). A noncomparative open-label study evaluating the effect of selegiline hydrochloride in a clinical setting. Vet Ther, 2(1), 24-39.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.