Psychoactive medications Flashcards
What is ultimate behaviour/ emotionality a product of?
personality traits and learning from life experiences
What is a normal emotional state?
- well-adapted
- good emotional homeostasis
What is an abnormal emotional state?
- poorly adapted
- poor emotional homeostasis
What might life events be?
- experiences of threat/fear
- situations of emotional conflict or frustration
- conditioned contextual associations with anziety
What does an event in an animal’s life cause?
additive effect of arousal and emotional responses –> animal emotional state becomes closer to the threshold
What are long term psychoactive drugs used for?
improves response to an event
WHat are short term psychoactive drugs used for?
to suppress memory of an event
Aims of psychoactive drugs
- reduce general anxiety
- reduce situational anxiety
- reduce fearfulness
- suppress memory of events
- changes only happen as a result of experience and medication
Why use psychoactive drugs?
- specific drug indication (separation anxiety)
- if emotion is so intense that it is interfering with therapy (intense anxiety/fear, phobia and risk to animal/ person/ property)
- animal’s suffering or distress could be alleviated with drug therapy
- if prognosis can be improved or improvement speeded up
3 phases of psychoactive drug therapy
- initiation
- maintenance
- withdrawal
What is initiation?
- first stage of psychoactive drug tx
- risk of adverse effects (may predispose aggression)
- changed emotionality (may make behaviour unpredictable, increased confidence/ disinhibition)
- delay in onset of main effects (can take 4-8 weeks)
What is maintenance?
- 2nd stage of psychoactive drug tx
- treatment continued until:
- end of period for which drug is licensed
- there is a period of normal behavior
- there is an indication that emotional component is less significant and behavioural modification alone will be successful
What is drug withdrawal?
- 3rd and final phase of psychoactive medication
- no info on datasheets for this
- unpleasant side effects well known in man (discontinuation syndrome is common with TCA/ SRI/ SSRI) that have a short half-life = clomipramine
- potential for recidivism if drug withdrawn suddenly
Name a drug class that has recidivism
Benzodiazepines: 80% cats have recidivism
How long should you reduce a drug dose for before finally stopping tx?
- 6 month tx = 6 weeks withdrawal
- 8 months tx = 8 weeks withdrawal, this is maximum amount of time for withdrawal (i.e. tx for more months than 8 should also have a 8 week withdrawal)
What are hazards of using medication?
- adverse effects
- therapeutic failure
- disinhibition (especially benzodiazepines, also TCA, SRI, SSRI drugs and acepromazine)
- excessive confidence and assertiveness (selegiline)
- owner overdependence (where they prioritise drugs over behavioral tx)
Adverse effect - clomipramine
- sedation
Name 3 psychoactive drug classes
- serotonergic
- dopaminergic
- gaba-ergic
Outline serotonergic reuptake inhibitor (SRI) psychoactive drugs
In anxiety and depression synaptic serotonin i slow, and receptors and up-regulated.
- IMMEDIATE EFFECT: increase the number of activated receptors on dendrite post-synaptic membrane, increase serotonin concentration
- DELAYED EFFECT: decrease post-synaptic receptors and pre-synaptic receptors and increase serotonin concentration (which causes behavior changes)
- DRUG WITHDRAWAL: persistent increased synaptic serotonin suppresses receptor expression
Name 4 serotonergic drug examples
- amitriptyline
- clomipramine
- fluoxetine
- sertraline
Action - TCA/ SRI/ SSRI drugs
They not only alter serotonin and noradrenaline reuptake, they also antagonise a range of other receptors causing adverse effects (e.g. antagonism of H1, M1 and alpha 1)
What do most psychoactive drugs have a balance between?
SRI and NRI
What is NRI?
Noradrenaline Reuptake Inhibitor
What is amitriptyline?
- a serotonergic drug
- a tricyclic antidepressant
- antagonises H1, M1, alpha1 (–> many side effects)
- SRI: NRI of 1:4
- USED for: anxiety, pain
Side effect - H1 antagonism
- weight gain
- sedation
Side effect - M1 antagonism
- constipation
- dry mouth
- urinary retention
Side effect - alpha1 antagonism
- hypotension
- sedation
What is clomipramine?
- a serotonergic drug
- a SRI and also a TCA
- antagonises H1, M1 and alpha1
- SRI: NRI of 5:1
- USE: anxiety, compulsive disorders
What is fluoxetine?
- a serotonergic drug
- an SSRI
- antagonises H1, M1 and alpha1
- SRI: NRI of 15:1
- USES: anxiety, compulsion, impulsivity, aggression
Define SSRI
Selective Serotonin Reuptake Inhibitor
What is feline hyperaesthesia syndrome?
- dilated pupils
- tail swishing
- shakes head
- bit and lick at flank when twitching
- apparent hallucinations
- run round house madly
Tx - feline hyperaesthesia syndrome
clomipramine
What is Fluoxetine?
commercial name for fluoxetine
What do you treat impulse aggression with?
fluoxetine (to ensure dog growls before biting/ attacking so less aggression is not impulsive and is actually warned first)
What is sertraline?
- a serotonergic drug
- SSRI
- SRI: NRI of 150:1 (increasingly selective but much reduced range of situations where they will be effective)
Specific use - amitriptyline
feline interstitial cystitis
Specific use - clomipramine - 5
- generalised anxiety
- separation anxiety
- compulsive disorder
- indoor spray marking (cats)
- feline hyperaesthesia syndrome
Specific uses - fluoxetine
- generalised anxiety
- separation anxiety
- compulsive disorder
- indoor spray marking (cats)
- impulsive aggression (e.g. owner directed)
- frustration-related aggression (cats)
Specific uses - sertraline
- generalised anxiety
- noise phobias
Adverse effects - amitripyline
- irritability
- agitation
- tachydysrhythmia
Adverse effects - TCA
- corneal drying
- TCAs that are strongly noradrenergic can cause explosive emotional reactions in man
Serotonergic drug interactions
- amitraz (v. strong reaction)
- opioids (respiratory dysfunction)
- MAOIs (selegiline)
- phenothiazines
Common adverse effects - serotonergic drugs - man
- headache
- abdominal pain
- mm rigidity
Serotonergic specific medical cautions
- CV dz (arrhythmias)
- Diabetes (TCA/ SRI are hyperglycaemic)
- Thyroid disease (altered TCA metabolism)
- Epilepsy
- narrow angle glaucoma
What is Trazodone?
- a serotonergic drug, an SARI
- not used on own but as a supplement to dogs on tx with clomipramine or fluoxetine which haven’t responded
- NL in dogs
- adjunct tx with dogs with noise phobia
- widely used as adjunct tx in people but risk of serotonin syndrome requires caution
Define SARI
Serotonin Receptor agonist and reuptake inhibitor (e.g. trazodone)
What is serotonin syndrome?
where there is excess serotonin that can –> coma, death
What is an example of a dopaminergic drug?
selegiline
What is selegiline?
- a dopaminergic drug
- a selective MAOIb = monoamine oxidase b inhibitor (drug blocks R on this molecule), but does has v low level of MAOIa inhibition
- can be given without dietary modification needed with MAOIa drugs
- other MAOI drugs cannot be subsitituted for selegiline
Main effects - selegiline/ dopaminergic drug
- mild anxiety reduction
- improved conditionability (even normal animals)
- increased exploratory and risk taking behaviour
- reduced fearfulness
Indications - dopaminergic drug (selegiline)
- CCD = canine cognitive dysfunction (‘dementia)
- fears and phobias
Adverse effects - selegiline/ dopaminergic drugs
- agitation
- GIT signs
- drowsiness
- MAN: headache, abdo pain, hallucinations
Drug interactions - selegiline/ dopaminergic drugs
- TCA/ SRI/ SSRI
- phenothiazines (ACP)
- potentiates benzodiazepines
- pethidine
Name an example of a GABA-ergic drug
Benzodiazepine
How do benzodiazepines work?
- target GABA-A ligand-gated ion channel on post-synaptic membrane –> increased Cl- transfer into post-synaptic cell (d/t secondary binding of the benzodiazpine to the GABA-A-R).
Main effects - benzodiazepines
- amnesia (anterograde and retrograde)
- anxiety reduction
- reduction in panic
- increased exploratory and risk taking behaviour
Adverse effects - benzodiazepines
- agitation (incl hyperexcitability)
- ataxia
- sedation
- amnesia
- recidivism
- tolerance
- disinhibition (esp aggression)
Main indications - benzodiazepines
Acute tx for panic (e.g. noise phobias)
