Retrospective study on the use of selegiline (Selgian®) in cats

© 1999 - Dr Joël Dehasse, Brussels (Belgium) (



Selegiline (SelgianR) has been used in cat behavior disorders.

27 cases from different veterinary practices (multicentric retrospective study) have been gathered using the same questionnaire and evaluation sheet. The inclusion criteria were that (1) the cat had to be evaluated at least once and at least after one month of treatment and (2) the questionnaire had to be adequately filled out.

90 signs were recorded at day zero. Investigators had then to designate the major symptoms presented by the cat. Only these signs were followed up. This explains the decrease in the number of the evaluated signs in relation to the signs recorded at day zero.


The 27 cats were divided in 16 (59,3%) females and 11 (40,7%) males with different breed characteristics: 18 European cats, 6 Siamese, 2 Burmese and 1 Persian. The age was reported at an average of 4,4 ± 3,4 years old, varying from 5 months to 15 years. The mean weight was 4,2 ± 2,7 kilos.

These cats had presented the problem behavior for an average of 17 months, half of them showing the problem for more than 12 months. The medium duration of the treatment was recorded at 73,0 ± 41,97 days (from 30 days to more than 150 days).

The dosage of selegiline was reported at an average of 1,3 ± 0,5 mg/kg once a day. There is a deviation due to one of the investigators prescribing SelgianR  at the dosage of 2 mg/day. The rectified average dose was around 1 mg/kg/day.


Crossed examination of data disclosed that there is no significant difference between the sexes on the most frequent signs recorded at day zero:

-         aggressive signs: 9 F, 7 M (total=16) Khi2=0,07.

-         alopecia: 7 F, 6 M (total = 13) Khi2= 0,16.

-         increased or stereotyped self-licking behavior (and onychophagia): 9 F, 6M (total=15) resulting in alopecia in 13 cats (7F, 6M).


A global assessment of the symptoms showed an improvement of 50 (70%) signs out of 71 recorded as major signs. With a placebo effect expectation of 50% improvement, this gives a Khi2 of 11,84 (very significant with P<0,005). When these symptoms are divided in 2 categories: productive signs (disorders generating behaviors and nuisances, and lack of inhibitory signs, like aggression, bulimia, insomnia, …) or deficit signs (inhibition, anorexia, hypersomnia, …), the analysis shows that 9 (90%) deficit signs (n=10) and 38 (72%) productive signs (n=53) were improved. Both categories were significant at the P<0,005 level (Khi2 respectively at 8,2 and 9,98). There is no significant difference between the improvement in both categories.


The individual examination of the signs recorded as major signs by the investigators showed improvement for:

-         territorial aggression between cats of the same household (cohabitation aggression): 5 (83%) improved (n=6).

-         Irritation and fear (self-defense) aggression: 3 improved (n=5)

-    Reduced appetite, hyporexia or anorexia: 5 improved (n=6)

-         Licking behavior: 10 (83%) improved (n=12)

-         Insomnia: 2 improved (n=2)

-         Soiling: 4 improved (n=4)

-         Urine spraying: 2 improved (n=2)

-         Fear: 2 improved (n=3)

-         Excessive vocalization (meowing): 2 improved (n=2)

-         Overactivity: 1 (n=2)


In the group of cats presenting some form of aggressive behavior at day zero (n=16), 10 presented also excessive self-licking behavior and 7 presented alopecia. 4 of these cats with alopecia and aggressive behavior were considered as major signs to be followed-up by he investigators: all 4 were improved (n=4).


The examination of the data showed that several disorders (collection of several symptoms) have been improved: for example

-         general anxiety: 7 (78%) improved (n=9).

-         Alopecia as a form of compulsive disorder (circumscribed or extensive alopecia): 7 (87,5%) improved (n=8) (note that alopecia was recorded in 13 cats at day zero but only as a major and followed up sign in 8 cats).


Selegiline has shown

-         little effect on hyperattachment: 1 improvement (n=3)

-         no effect on inappropriate predatory aggression on people expressed by cats living in a closed environment (apartment): 0 improvement (n=3).


No side effect related to the treatment was reported.

Several owners mentioned problems of compliance, several cats becoming reluctant and fearful to take the tablet after a while. We can very probably impute this compliance reluctance to the bitter taste of the drug.


Selegiline is a phenylethylamine (PEA) analogue that inhibits irreversibly the B-monoamine-oxydase enzyme (PEA is a potent thymoanaleptic drug) (1). This may lead to an increase of the synaptic occupancy of PEA and reduces the catabolism of other monoamines, like dopamine, noradrenaline and tyramine. PEA seems to play a neuromodulation role for dopamine and noradrenaline (2). Selegiline also inhibits the recapture of dopamine (3) and, to a lesser extent, of noradrenaline (4).

Selegiline increases the action of superoxyde dismutase (SOD) and of catalase enzymes, both responsible for the detoxification of free radicals in the brain, particularly metabolites of dopamine catabolism.

Selegiline seems to act as a modulator or regulator of emotions and emotional pathologies and mood variations (or mood disorders). It is as effective in productive and deficit disorders.

This study is not a placebo-controlled study and therefore doesn’t pretend to be a demonstration of the efficacy of selegiline in cats. However, the cases analyzed here give some light about the potential interest of selegiline on some of the most frequent disorders/signs encountered in cats i.e. generalized anxiety, compulsive licking and several types of aggression. Our personal findings and those from others showed that the dosage should be increased up to 1mg/kg for the treatment of behavioral disorders to achieve comparable results  to the ones seen in dogs at 0.5 mg/kg.

 As selegiline has shown positive effects on compulsive disorders both in dogs (6) (7) (8) and in cats, it would be interesting to compare its effect to a typical SSRI drug. This may shed some light on the part dopamine may play in compulsive licking and other compulsive disorders.


SelgianR has proved to be a resourceful drug to treat emotional disorders accompanied by productive signs or deficit symptoms in cats. Further studies are required to demonstrate the efficacy of the product on specific disorders.


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Phenylisopropylmethyl-propinylamine HCL, E250, a psychoenergiser with a new spectrum of activity.

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2-Phenylethylamine : a modulator of cathecholamine transmission in the mammalian central nervous system ?

Journal of Neurochemistry. 1990. 55 (6). 1827-1837.

3) HARSING L. and Al :

Inhibition of dopamine uptake in rat striatum : a possible correlation between dopamine uptake and possible acetylcholine release inhibition,

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Some puzzling Pharmacological Effects of Monoamine Oxidase Inhibitors.

Advances in Biochemical Psychopharmacology. 1972. Vol. 5. 393 - 408.

5) CARILLO and Al :

(-) Deprenyl increases activities of Super Oxyde Dismutase in Striatum of Dog Brain, Life Sciences,1994, Vol 54, no 20, pp1483-1489.


Treatment of stereotypies and compulsive disorders in dogs and cats, in Proceedings of the 1st ESVCE(=-AMEVE Congress of Clinical Veterinary Ethology, Madrid, December 1998, pp 155-164

7) PAGEAT P. :

Pathologie du Comportement du chien,

Editions du Point Vétérinaire, 2nd edition, PARIS 1998.


Clinical  management of stereotypies in dogs, in Proceedings of the annual 1998 AVSAB meeting, Baltimore, July 1998.


Dr Joël Dehasse
Behaviorist veterinarian