Behaviour modifiers Flashcards
(26 cards)
What are the slow acting anti-depressants?
-TCAs: Clomipramine, Amitriptyline
-SSRIs: Fluxetine, Sertraline
What are the fast acting anti-depressants?
trazodone
What are the alpha-2s?
-clonidine
-dexmedetomidine
What causes depression?
monoamine theory of depression
-reserpine ( caused depression in animal models and people)
-releases stored monoamines (serotonin, Nadr, and dopamine) from synaptic vessicles
-this leads to their rapid metabolism by the cytoplasmic monoamine oxidases
Serotonin and Noradrenaline
Function is to modulate mood, motivation, learning, and reasoning
Dopamine
Role in motivation, goal directed thinking
Function of TCAs
inhibit reuptake of serotonin and Nadr
-decreases the metabolism of serotonin and Nadr
- it decreases their metabolism by decreasing exposure of monoamines to monoamine oxidases thereby permitting their effect
Why do TCAs and SSRIs have a delayed onset of action?
Need long term treatment for them to be effective
-autoreceptors eventually become desensitised (clinical effect)
*Stimulating autoinhibtory feedback more than normal, after chronic stimulation through activation of pre-synaptic receptors; they become desensitized
What is the only registered veterinary tricyclic antidepressants?
Clomipramine
-delayed effectiveness
Clomipramine indications
-For situations of unavoidable prolonged exposure to the trigger stimuli
-Should be given daily even if trigger is not constantly present
Dogs:
o Separation anxiety, destructiveness, excessive vocalization and OCD (tail chaising, excessive grooming)
Cats:
o Used for aggression, inappropriate urination/spraying, excessive grooming, anxiety, excessive vocalization
Clomipramine contraindications?
-antimuscarinic effect (blocks the action of acetylcholine)
-avoid if suspected glaucoma
What are the registered selective serotonin reuptake inhibitors
Fluoxetine “reconcile”, sertraline
Indications of SSRIs
*dogs: OCD (e.g. lick granulomas, tail mutilation), separation anxiety, aggression (be careful – may decrease inhibition)
*cats: urine spraying, aggression, psychogenic alopecia
What SSRI is used off label in animals
-sertraline
Trazodone MOA
Can be an agonist at some serotonin receptors, and antagonist at others
-antagonist at 5-HT2A and 5-HT2B receptors
-partial agonist at 5-HT1A
Trazodone indications
*Atypical antidepressant for dogs and cats
*Comparatively (to TCAs, SSRIs) rapid onset of action ~ 1hr and so try and give 1 hr before anticipated anxiety-inducing stimulus
*Used for anxiety situations administered an hour before stressful stimulus
Why should you be mindful when prescribing trazodone?
-if used with serotonin increasing drugs, risk of serotonin syndrome
Gabapentin MOA
Thought to be inhibition of pre-synaptic calcium channels preventing release of monoamines into the synapse
Gabapentin indications
reduce anxiety in dogs and cats
-often no sedation
Clonidine
-oral alpha-2 agonist
-most alpha-2 have poor bioavailability
What alpha-2 agonist has good oral bioavailability?
-Clonidine
Clonidine indications
*Better suited for behavioural issues driven by arousal and vigilance.
Used for:
oFear-based aggression (meeting unfamiliar people/animals on walks), noise phobias, and separation anxiety
oCommon adjunct to SSRIs
Orotransmucosal dexmedetomidine “sileo”
-registered to reduce anxiety and noise phobias
-dosage is on a surface area basis
Why do you have to be mindful of orotransmucosal drugs with dental disease?
-increased gingival vascularity may accelerate absorption increasing the depth of sedation
-blood supply to area of drug molecules is very important, inflamed gums, absorption will occur rapidly
