Medicines In Psychiatry Flashcards
4 types of treatments?
-Chemical – drugs/medicines (+Immunotherapy), e.g. drugs for psychosis e.g. drugs for depression
-Electrical stimulation, e.g. ECT for depression e.g. neurostimulation for pain syndromes
-Structural rearrangement - surgery & orthopaedics, e.g. psychosurgery/deep brain stimulation for severe depression
-Talking (pycho) therapies, e.g Cognitive Behaviour Therapy (CBT) e.g. exposure for phobias
How does WHO classification system classify drugs?
Based on chemical structure
What is the problem with classifying drugs based on what illness they treat?
Some drugs treat multiple illnesses
Examples of drugs that block enzyme activities?
-monoamine oxidase inhibitors [MAOIs] for anxiety and depression
-acetylcholinesterase inhibitors for dementias
-lithium blocks glycogen synthase kinase for mood stability
Examples of receptor blockers (antagonists)?
-dopamine receptor blockers for schizophrenia
-serotonin receptor subtype antagonists for depression
-histamine receptor antagonists for sleep
antagonists block endogenous agonist binding to the receptor
Examples of agonists?
-benzodiazepines enhance GABA for sleep
-guanfacine enhance noradrenaline for ADHD
agonists mimic the endogenous agonist and stimulate the receptor
Reuptake site targeting medicines? Block
citalopram – enhances serotonin (= serotonin reuptake inhibitor or SRI)– for depression and anxiety
desipramine – noradrenaline reuptake inhibitor (NRI)= enhances noradrenaline - for depression
methylphenidate – dopamine reuptake inhibitor (DRI)- enhances dopamine - for ADHD
Reuptake site targeting medicines? Enhance
amfetamine for ADHD
Sodium ion channel blocker medicines?
-sodium valproate- epilepsy and mood stabilisation
-carbamazepine - epilepsy and mood stabilisation
Calcium ion channel blocker medicine?
gabapentin & pregabalin – epilepsy anxiety
Fast acting neurotransmitters?
Excitatory – glutamate = > 80% of all neurons - pyramidal cells
Inhibitory – GABA = 15% - inter-neurons
content e.g. of memory, movement, vision etc.
Slow acting neurotransmitters?
dopamine – serotonin – noradrenaline-acetylcholine
endorphins and other peptides
emotions, drives, valence of memory etc.
Excess glutamate disorder with treatment
Epilepsy - perampanel
Alcoholism - acamprosate, ketamine
treatments all blockers
GABA deficiency disorder with treatment?
Anxiety - benzodiazepines (GABA enhancer)
5HT deficiency disorders and treatments
Depression and anxiety - SRIs and MAOIs - serotonin enhancers
Dopamine excess disorder and treatment?
Psychosis - dopamine receptor blockers
Noradrenaline excess and treatment?
Nightmares - prazosin (blocker)
Acetylcholine deficiency disorder and treatment?
Impaired memory/dementia - acetylcholine esterase enzyme blockers
Partial agonists?
Lower max efficacy than full agonists
Improved safety
In states of high neurotransmitter or excess agonist medicine, can act as an antagonist
Aripiprazole - anti-psychotic with less Parkinsonism symptoms
Inverse agonists
Opposite effects to agonists
GABA - reverse amnestied effects
Histamine - increases attention
Allosteric modulation
Sites on receptors where things can bind other than target protein
GABA binds to GABA receptor = orthosteric site -> enhanced chloride ion conductance -> inhibits neurones -> calms brain
Benzodiazepines, barbiturates, alcohol, neurosteroids similarity?
All act at allosteric sites on same protein complex
Enhance action of GABA -> sedation, sleep, reduced anxiety, anti-epilepsy
Selectivity cons?
If too selective, can totally block receptor - negative
If very unselective, can bind to other receptors so cause adverse effects. Can also be helpful - block other side effects