Major Uses

Selegiline increases concentration of dopamine, a neurotransmitter in the brain. This action stimulates dopamine receptors and improves many cognitive process to positively affect brain function.

Selegiline's primary use is to treat canine cognitive dysfunction syndrome, or canine senility, in dogs. It may also be used in the treatment of Cushing's disease. The drug is very rarely used in cats and should only be used in dogs once a diagnosis of canine cognitive dysfunction syndrome is given.

Common Precautions

Side effects associated with proper use of selegiline are not common and are generally mild. These may include restlessness, vomiting, lethargy, and diarrhea. Itchy skin, loss of appetite, drooling, disorientation, listlessness, tremors, and diminished hearing are other possible adverse effects.

Selegiline is not for use in pregnant, breeding, or lactating animals. It should also not be used in the treatment of aggression in dogs or other animals. Selegiline should only be used in dogs with a diagnosis of canine cognitive dysfunction syndrome and not in those with other causes of senility, such as brain tumors, medication reactions, disorders of body chemistry, or others. The drug is not helpful as a treatment for adrenal gland-based Cushing's disease. It should only be used to treat pituitary-based Cushing's disease.

Selegiline is known to interact with some other drugs and supplements, such as antidepressants, amitraz, phenylpropanolamine, and certain narcotics. The drug should not be taken within 5 weeks of using any monoamine oxidase inhibitor and should not be given with aged cheese. These interactions can be very serious and potentially cause death. It is important to disclose all medications and supplements being taken before beginning treatment with selegiline.

Selegiline should not be used in animals with a known allergy or hypersensitivity to the drug. At three times the recommended dose, selegiline may cause salivation, dehydration, weight loss, panting, and poor pupil response to light. An overdose of this drug is potentially fatal and should be considered a medical emergency. Any known or suspected overdose should be reported to a veterinarian right away.


Selegiline should be stored in its original packaging, out of the reach of children and animals, and at room temperature.


Selegiline is available in tablet form in strengths of 2 mg, 5 mg, 10 mg, 15 mg, and 30 mg. The typical dose of selegiline to treat hyperadrenocorticism and canine cognitive dysfunction is 0.25 to 0.5 mg/lb (0.5 to 1 mg/kg) once daily. After two months of a treatment, the dog should be re-evaluated for a possible increase in dose. Selegiline is generally given in the morning.

If a dose of selegiline is missed, it should be administered as soon as possible. If it is 16 hours or less before the next dose, the missed dose should be skipped and the normal schedule resumed. Two doses of this medication should not be given at once.