(-) selegiline hydrochloride is an inhibitor of monoamine oxidase (IMAO-B) at the therapeutic dose in the dog; thus it modifies the concentration of monoaminergic neurotransmitters.

(–) selegiline hydrochloride is quickly absorbed after oral administration. The oral bioavailability ranges from 65 to 95 % in the dog.

Selegiline binds rapidly and durably onto the specific cerebral receptors. The duration of the pharmacological effect following such binding is independent of the maintenance of blood levels.

Selegiline is quickly metabolised into l-desmethylselegiline, l‑amphetamine and l‑metamphetamine. At the therapeutic dose recommended in the dog, these derivatives have no pharmacological activity.

Repeated administration of Selgian showed the absence of any cumulative effect after 91 days in the beagle dog.