Behaviour Modifying Drugs Flashcards
Drug Classes used to modify behaviour target key neurotransmitters. These are (5):
q Norepinephrine
q Dopamine
q Serotonin
q GABA
q Acetylcholine
most drugs used to modify behaviour in vet med are meant for what species?
Currently, most drugs used to modify behaviour in veterinary medicine are extra-label use of human products
common effects of behaviour modifying drugs, in general
q Decrease arousal
q Decrease excitability
q Decrease impulsivity
q Promote calming
are behaviour modifying drugs commonly curative? what can they be combined with?
-rarely curative
-can decrease latency response to behaviour modifying techniques
common categories of major behaviour problems
-aggression
-compulsive disorders (stereotypes)
-fear, anxiety, phobias
what types of aggression are there and which type is more concerning?
Offensive versus defensive aggression
q Offensive generally more of a concern
subtypes of aggression include:
Fear
Possessive
Dominance
Maternal
Territorial
Drug classes that increase central serotonergic activity may have what effects on aggression?
Decrease
-decreased tendency to engage in sudden outbursts
-increased threshold of tolerance to potentially aggressive stimuli
what are obsessions vs compulsions? what drugs are useful for this?
q Obsessions are persistent thoughts, ideas, impulses or images that cause marked distress
q Compulsions are repetitive behaviours eg. stereotypies
q TCA’s, SSRI’s and Opioid antagonists can be beneficial
when does fear become a problem? what are anxiety and phobias, and what drugs can we use to control behaviours related to these?
q Fear is a normal behaviour, but when excessive relative to the stimulus, then it is a problem
q Anxiety is marked by apprehension of “dread or a sense of danger”
q Phobias– fears of specific objects, persons or situations that result in panic
q These types of behaviour generally benefit from anxiolytics
treatment duration for unwanted behaviours depends on what? most patients receive treatment over what time frame?
o Unwanted behaviour and species
o Drug class
o The “individual”
o Owner’s ability to comply with all aspects of therapy
n Most patients are on long-term drug therapy
o Most drugs are not given “as needed”
o Severe or refractory cases may require life-long drug and behavior modification !
ideally, how will we change the dose of behaviour drugs over time?
n Ideally, gradually reduce (taper) dose; based on individual’s response
o Monitor signs while decreasing dose; identification of lowest effective dose if problem returns
o Withdrawal symptoms generally not significant
What if the behaviour drug does not work/isn’t working?
n Remember clinical responses take time
o ~5 half-lives before steady-state
o Modification of receptor systems also takes time
n Dose modification possible; caution with ADRs
n Consider switching drug classes
n Consider combination drug therapy
is transdermal drug therapy useful for behavioural cases?
n Generally, has yielded poor to variable drug levels and efficacy
n Useful in animals that are challenging to medicate orally long-term
q Knowledge of drug pharmacokinetics key
q Collaboration with experienced pharmacist; compounding required
what are the general characteristics of phsychotropic drugs in vet med? what are their chemical properties? what tissues can they penetrate? where are they metabolized?
o Many behaviour drugs used in veterinary medicine are weak bases
> Good lipophilicity
> Protein binding generally low
o CNS penetration is generally very good
> BBB and blood-CSF barrier
o Most behavior drugs are metabolized by liver
o Species variations in metabolism (CYP450’s)
Principal anxiolytics in veterinary medicine are
benzodiazepines (BZD’s)
mechanism of action of benzodiazepines?
o Work through potentiation of the GABA-A receptors
n Anxiolytic effects believed due to modulation of 5-HT and NE neurons in the CNS
mechanism of action of benzodiazepines?
o Work through potentiation of the GABA-A receptors
n Anxiolytic effects believed due to modulation of 5-HT and NE neurons in the CNS
effects of benzodiazepines
anxiolytic
o Anxiolytic effects separate from general CNS depressant effects; dose-related
n Anxiolytic effects can be immediate; may increase with continued dosing
n Other general CNS depressant effects include:
>central muscle relaxation, sedation
>seizure suppression
when do we use benzodiazepines
o Used in fear and anxiety related problems
n Separation and general anxiety
n Noise and storm phobia where immediate effects desired
>as needed basis
are benzodiazepines safe? what are some possible side effects?
o BZDs have an excellent history of safe use
n Disinhibition possible; caution or avoid use in cases of aggression
n Paradoxical excitement and amnesia possible
n Idiosyncratic hepatotoxicity in cats possible with diazepam; not yet seen with other BZDs
n Sedation, muscle relaxation, ataxia and hyperphagia
benzodiazepines used in vet med
Diazepam
Alprazolam
Lorazepam
what is flumazenil? how is it used?
BZD antagonist that may be employed to…..
n reverse overdose effects of BZD
n reverse unwanted behavior eg. paradoxical excitement, while taking BZD’s
use of diazepam? considerations and drawbacks?
n Has short half-life in dogs (~1 hr) compared to cats (~5.5 hr)
o Active metabolites with longer-half lives make it suitable for chronic use in cats only
n Potentially disappointing for immediate effects
o Higher doses needed in panic states ?
o Daily use over as needed basis ?
use of diazepam? considerations and drawbacks?
n Has short half-life in dogs (~1 hr) compared to cats (~5.5 hr)
o Active metabolites with longer-half lives make it suitable for chronic use in cats only
n Potentially disappointing for immediate effects
o Higher doses needed in panic states ?
o Daily use over as needed basis ?
what is alprazolam and what is its use?
anxiolytic, BZD
o Higher potency BZD; promising in dogs with panic disorders where a rapid response is needed
o Higher doses may also be needed for panic states over generalized anxiety