Psychopharmacology for Psychiatry Flashcards
What are the 4 main psychiatric treatments?
- chemical (drugs + immunotherapies)
- electrical stimulation (ECT)
- structural rearrangement (psychosurgery/deep brain stimulation)
- talking therapies (CBT)
What is the advantage of classifying psychiatric drugs based on their chemical structure?
each drug has a unique structure, easy to allocate data.
What is the disadvantage of classifying psychiatric drugs based on their chemical structure?
no use in clinical decision making
What is the advantage of classifying psychiatric drugs based on the disease that they treat?
easy for doctors to choose drugs as they make diagnosises
What is the disadvantages of classifying psychiatric drugs based on the disease that they treat?
- many psychiatric drugs are used in several disorders
- most disorders have multiple symptoms and may not all be treated with one drug
What is classifying psychiatric drugs based on their pharmacology?
neuroscience based nomenclature (NbN)
What are the 4 different drug targets?
- receptors
- neurotransmitter reuptake sites
- ion channels
- enzymes
What are some examples of drugs that block enzyme activity?
- monoamine oxidase inhibitors (depression)
- acetylcholinesterase inhibitors (dementia)
- lithium (bipolar)
What does lithium block?
glycogen synthase kinase - for mood stability
What are some examples of receptors which drugs (antagonists) block?
- dopamine receptors
- serotonin receptors
- histamine receptors
What are dopamine receptor blockers used to treat?
schizophrenia
What are serotonin receptor subtype antagonists used to treat?
depression
What are histamine receptor antagonists used to treat?
sleep
What are some examples of drug agonists?
- benzodiazepines
- guanfacine
What do benzodiazepines do?
- enhance GABA
- help with sleep
What does guanfacine do?
- enhance noradrenaline
- helps with ADHD
What do reuptake site blockers do?
- block reuptake sites
- increase neurotransmitter concentration in the synapse
- enhance post-synaptic receptor activity
What are some examples of reuptake blockers?
- citalopram
- desipramine
- methylphenidate
What does citalopram do?
- enhances serotonin
- serotonin reuptake inhibitor (SRI)
- treats depression and anxiety
What does desipramine do?
- noradrenaline reuptake inhibitor (NRI)
- enhances noradrenaline
- treats depression
What does methylphenidate do?
- dopamine reuptake inhibitor (DRI)
- enhances dopamine
- treats ADHD
Which drugs swap reuptake site direction to enhance release?
- amfetamine (for ADHD)
What do drugs that target Ion Channels do?
block channels to reduce neuronal excitability
What are some examples of drugs that block sodium channels?
- sodium valproate
- carbamazepine
What do sodium valproate and carbamazepine treat?
epilepsy and mood stabilisation
What are some examples of calcium channel blockers?
- gabapentin
- pregabalin
What do gabapentin and pregabalin treat?
epilepsy anxiety
How would you describe fast acting neurotransmitters?
on-off switch
What is an example of an excitatory fast acting neurotransmitters?
Glutamate
80% of all neurons
pyramidal cells
What is an example of an inhibitory fast acting neurotransmitters?
GABA
15% of interneurons
What do fast-acting neurons tend to be involved in?
- memory
- movement
- vision
How would you describe slow acting neurons?
modulators
How common are slow-acting neurons?
5% of all neurons
What are some examples of slow acting neurotransmitters?
- dopamine
- serotonin
- noradrenaline
- acetylcholine
- endorphins
What do fast-acting neurotransmitters tend to be involved in?
- emotions
- drive
- valence of memory
What is epilepsy caused by?
excess glutamate
What drug can be used to treat excess glutamate in epilepsy?
perampanel - glutamate blocker
What is alcoholism caused by?
excess glutamate
What drugs can be used to treat excess glutamate in alcoholism?
- acamprosate
- ketamine
(glutamate blockers)
What is thought to cause anxiety?
GABA deficiency
What drug can be used to treat a GABA deficiency?
benzodiazapine - GABA enhancer
What is thought to be caused by a 5-HT deficiency?
depression and anxiety
What can be used to treat a 5-HT deficiency?
SRIs
MAOIs
(serotonin enhancers)
What is thought to be caused by excess dopamine?
psychosis
What can be used to treat excess dopamine?
dopamine receptor blockers
What can be caused by excess noradrenaline?
nightmares
What can be used to treat excessive noradrenaline?
prazosin - noradrenaline blocker
What is caused by a acetylcholine deficiency?
impaired memory/dementia
What is the treatment for a deficiency in acetylcholine?
acetylcholine esterase enzyme blockers
What do most drugs for depression act on?
the 5-HT systems
What is the difference between partial and full agonists?
partial agonists have a lower maximum efficacy than full agonists
What are the advantages of using a partial agonist over a full agonist?
- improved safety (especially in overdose)
- combats hyperactivity while still maintaining the necessary amount of the neurotransmitter
- in states of high neurotransmitter or excess agonist medicine can act as an antagonist
What are inverse agonists?
drugs that have the the opposite effects to agonists but don’t block receptors like an antagonist
What is allosteric modulation?
When drugs work on different sites on the target proteins compared to the endogenous neurotransmitter
What is an orthosteric site?
the site that the desired substrate binds to
What is an allosteric site?
a different binding site of the substance, but on the same protein complex
What happens when GABA binds to the GABA receptor?
- enhances Cl ion conductance
- inhibits neurons
- calms the brain
What happens when benzodiazepines, barbituates, alcohol and neurosteroids bind to the allosteric point on the GABA receptor?
- enhances the action of GABA
- sedation
- sleep, reduced anxiety, anti-epilepsy
What is the selectivity of haloperidol?
- highly selective for the dopamine receptor
- adverse effects are due to dopamine receptor block
What is the selectivity of clozapine?
- non-selective
- lots of adverse effects due to off-target effects
(eg; sedation, weight gain, metabolic syndrome)
What is the selectivity of amitriptyline?
low, also binds to histamine and acetylcholine receptors causing adverse effects
What is the selectivity of citalopram?
- selective SRI
- adverse effects are solely due to increased serotonin
What do agonist drugs do?
Stimulate/ enhance receptors
What does the partial agonist buprenorphine treat?
Heroin addiction
What does the partial agonist aripiprazole treat?
- dopamine receptor partial agonist
- treats psychosis along
- better treatment than haloperidol
What is varenicline used to treat?
Nicotine addiction
