Selegiline
L-deprenyl
Also known as: Selgian · Anipryl · L-deprenyl · selegiline hydrochloride
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Behavioural disorders and cognitive dysfunction | 0.5-1 mg/kg | PO | q24h | minimum of 2 months | 🌍 EU |
- Behavioural disorders and cognitive dysfunction: Treatment can be stopped suddenly without gradual dose reduction.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Cognitive decline in older cats | 1 mg/kg | PO | q24h | Not specified | 🌍 EU |
- Cognitive decline in older cats: Treatment can be stopped suddenly without gradual dose reduction.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Selegiline (L-deprenyl) is a monoamine oxidase inhibitor authorized for the treatment of behavioural disorders of purely emotional origin, such as depression and anxiety. It is often used in association with behaviour therapy for conditions involving overactivity, separation problems, generalized phobia, and unsociable behaviour.
These emotional disorders are typically characterized by modifications in feeding, drinking, autostimulatory behaviour, sleep, exploratory behaviour, fear/irritation-related aggression, and somatic disorders (e.g., tachycardia, emotional micturition).
Clinical Pearl: Selegiline is highly indicated for canine cognitive dysfunction (CCD), especially when associated with anxiety or social withdrawal, and can also be used to treat signs of cognitive decline in older cats. Uniquely, treatment can be stopped suddenly without the need for gradual dose reduction.
Mechanism of action
Selegiline modifies the concentration of monoaminergic neurotransmitters, especially phenylethylamine and dopamine, by selectively inhibiting the activity of Type-B monoamine oxidase (MAO-B), the enzyme that normally breaks down these chemicals.
MAO-B inhibition → decreased breakdown of dopamine → increased dopamine concentrations in the CNS. It also appears to possess neuroprotective properties.
Safety & warnings
Contraindications
- Known sensitivity to selegiline
- Lactating bitches (acts on prolactin secretion)
- Pregnant bitches
Adverse effects
- No specific adverse reactions are listed in the monograph
- Clinical Pearl: May occasionally cause mild gastrointestinal upset, restlessness, or lethargy
Precautions
Normal safety and handling precautions should be observed.
Warning: Do not use in pregnant or lactating bitches due to its effects on prolactin secretion. Strict washout periods are required when switching to or from other psychoactive medications (e.g., TCAs, SSRIs).
Drug interactions
Should not be administered concurrently or within 24 hours before/after use
Contraindicated concurrent use
Contraindicated concurrent use
Potential MAOI interaction; contraindicated
Contraindicated concurrent use
Potentiates the effect of morphine
Potential interaction exists
Potential interaction exists
Potential interaction exists
Do not use selegiline for at least 2-3 weeks after TCA use
Do not use selegiline for at least 6 weeks after long-term fluoxetine use
Monitoring
- Improvement in behavioural signs (anxiety, phobias, social withdrawal)
- Improvement in cognitive function (disorientation, sleep-wake cycle alterations)
- Adverse drug interactions if other medications are introduced
Overdose
No specific overdose information is provided in the monograph.
Clinical Pearl: Overdoses of MAOIs can lead to signs of serotonin syndrome or excessive dopaminergic stimulation, including hyperthermia, tachycardia, tremors, and agitation. Treatment is supportive.
Available products
Formulations
- 4 mg oral tablet
- 10 mg oral tablet
Veterinary
- 4 mg tablets
- 10 mg tablets
Regulatory status
Approved for canine cognitive dysfunction and pituitary-dependent hyperadrenocorticism in the US.
POM-V classification.
POM-V classification.
No regulatory data for: 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Normal precautions should be observed. Store in a cool, dry place away from direct sunlight.
Client information
Selegiline is used to help manage behavioural issues like anxiety, phobias, and cognitive dysfunction (dementia) in older pets.
- Administration: Give the medication exactly as prescribed by your veterinarian. It usually takes several weeks (at least 2 months) to see the full benefits.
- Stopping the drug: Unlike some other behavioural medications, selegiline can be stopped suddenly without needing to slowly reduce the dose.
- Important Warnings: Inform your vet of all medications, supplements, or tick collars (especially those containing amitraz) your pet is using, as selegiline can have severe interactions with many other drugs.
- Pregnancy: Do not use in pregnant or nursing animals.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.