Psychotherapeutic drugs Flashcards
What is a psychotropic drug?
- ## Affects ‘mood’ or behaviour
What does benzodiazepine do and what is an example drug?
- May be useful for minimising short-term anxiety in dogs. Central skeletal muscle relaxant and anti-seizuring medication
- E.g. Diazepam
What is a tricuclic antidepressant (TCA) and what is an example drug?
- May be indicated for minimising obsessive-compulsive actions, separation anxiety and may reduce urine spraying in desexed female cats; provides some central and spinal analgesia
- E.g. clomipramine
What is a selective serotonin reuptake inhibitor (SSRI) and what are 2 examples?
- Indicated for separation anxiety; provides some central and spinal analgesia
- Fluoxetine and trazadone
What is a GABA (Gamma-amino butyric acid) and wjat is an example?
- Significant inhibitory CNS neurotransmitter
- Gabapentin
What is a glutamate?
Significant excitatory CNS neurotransmitter
When might a psychotropic drug be used?
- Commonly used in dogs, cats, horses and other species
- Used for anxiety and/or inappropriate behaviour and/or senility
Do we use psychotropic drugs to induce sedation?
No, they are not expected or intended to induce sedation
Where does our knowledge on psychotropic drugs come from?
- Knowledge comes from humand an lab animal evidence
- There are limited evidence based findings in companion animals at this time
What needs to be considered prior to the use of a psychotropic drug?
- Behavioural modification
- Is there an underlying physiological or medical problem contributing to the problem behaviour?
What are the three main monoamine and amino acid CNS neurotransmitters and what are they responsible for?
- Dopamine: Too much dopamine is associated with stereotypies
- Noradrenaline: Dopamine converted to noradrenaline, need good levels to allow us to learn/respond to a rewards system
- Serotonin - Important in mood and behaviour, calms down the animal. Can help with aggression
What are monoamines?
- Collections of neurons – cell bodies come together as ‘nuclei’ in brainstem & basal forebrain; these cells secrete monoamine neurotransmitters - Project to cortex
Give two examples of exogenous pheremones that mimic endogenous pheremones available on the market?
Adaptil (dog appeasing hormone) and feliway (feline facial pheremone)
Is diazepam commonly used in veterinary medicine?
No, we have betetr benzodiazepans for vet med
- long term effects = can be hepatotoxic
- short acting
Is diazepam commonly used in veterinary medicine?
No, we have betetr benzodiazepans for vet med
- long term effects = can be hepatotoxic
- short acting
What benzos are more commonly used in vet med?
Alazopram or midazolam
What are some examples of other psychotropic drugs commonly used in vet med?
- Monoamine oxidase inhibitor (MAO-I): selegiline (anipryl)
- Tricyclic and tetracyclic antidepressants (TCA): clomipramine (clomicalm)
- SSRIs: fluoxetine (reconcile) and trazadone
How does a monoamine oxidase inhibitor work?
- Inhibits dopamine breakdown & increases dopamine released into synaptic cleft
- also inhibits release of ACTH from pituitary – occasional treatment of pituitary induced hyperadrenocorticism
- May take 3 months to see full clinical/behavioural effects
- Not widely used anymore in veterinary medicine
What might we see in terms of behaviour if there is an overdose of MOA-I?
Stereotypies - increasing dopamine
What are some adverse side effects associated with MOA-I?
- Git signs (ALWAYS a risk when taking a drug orally), anorexia, Pruritus, hypersalivation, listlessness, reduces hearing
How do tricyclic & tetracyclic antidepressants (TCA) work?
- Compete with NA & serotonin at site of ‘uptake 1’
- Time to see effects 2 – 4 weeks
What are some side effects assoicated with tricyclic & tetracyclic antidepressants (TCA)?
antagonists at
* Muscarinic receptors (milder effects than atropine)
* H1 & H2 receptors
* α1 adrenoreceptors
* Overdose = arrhythmias (increase in nor adrenaline in synaptic clefts)
* Registered for use in cats
* Cats more sensitive to these drugs (lower dosage for cats)
When might tricyclic & tetracyclic antidepressants (TCA) be used?
- Used in conjunction with behaviour modification training
- Dogs: aid in treatment of anxiety disorders in dogs such as destructiveness, fears & phobias (e.g. noise phobia); excessive vocalisation & loss of toilet control associated with canine separation anxiety as well as OCD (acral lick dermatitis, exessive grooming and tail chasing)
- Cats: can aid in the treatment of urine spraying
How do SSRIs work? What are some examples of them?
- Competes with 5-HT (serotonin) at site of ‘uptake 1’ -> ↑ 5-HT (serotonin) in synaptic cleft
- Takes weeks before we see clinical change
- Examples include fluoxetine and trazadone
Is fluoxetine registered for use in cats?
No, only registered for use in dogs
When might SSRIs be used?
To treat separation anciety in dogs, specifically NOT recommended for the treatment of aggression (on the label). Marketed with a behavioural BOND training plan, if no improvement after 8 weeks then the patient needs to be ree-evaluated
What are some side effects assoicated with SSRIs?
- anti-cholinergic effects,
- decreased appetite (including anorexia),
- lethargy, somnolence, seizures
What are the approximate period to see clinical positive effects for MOIs, TCAs and SSRIs?
NOTE: Individual drugs need to be tried to see which one works best with fewer side effects for each patient
- MOI = 3 months
- TCAs = 1 month
- SSRIs = 2 months
What do we want to avoid when administering psychotherapeutic drugs?
- Administering TCAs or SSRIs together as it may lead to ‘serotonin syndrome’ – tremor, hyperthermia, CV collapse (tachycardia, hypertension)
- Usually when drugs that block serotonin uptake are given together
o In dogs and cats usually due to an inadvertent overdose of SSRIs
Can you stop TCAs or SSRIs abruptly?
No, it is recommended to taper off these drugs
- Withdraw one class of psychotropic agent prior to starting another one
- washout periods: TCAs (2 weeks in dogs), fluoxetine (6 weeks) and other SSRIs (2 weeks)
