Drugs used in Psychiatric Disease Flashcards
What are the key symptoms of depression?
Core = low mood, anhedonia, decreased energy
Secondary = decreased appetite, sleep disturbance, hopelessness, irritability, reduced libido
Outline the pathophysiological theories of depression
1) Monoamine hypothesis = def of monoamine neurotransmitters (NA, serotonin). Monoamine oxidase inhibitors (MAOIs) block the enzyme monoamine oxidase from destroying neurotransmitters
2) Receptor hypothesis = abnormality in receptors for monoamine transmission leads to depression
3) Gene expression = problem within the molecular events distal to the receptor
Give an example of an SSRI
Citalopram
What is the mechanism of SSRIs?
Inhibit the reuptake of serotonin into the presynaptic cell
Increased serotonin the synaptic cleft
What are the ADRs of SSRIs?
Anorexia, nausea, diarrhoea
Overdose = reasonable safe on its own
Give an example of a TCA
Amitriptyline
What is the mechanism of TCAs?
1) inhibition of NA uptake = enhanced NA neurotransmission
2) muscarinic cholinergic blockade = reduced cholinergic neurotransmission
3) A1-adrenoceptor blockade = suppression of NA neurotransmission
What are the ADRs of TCAs?
CNS – sedation, lower seizure threshold
ANS – reduction in glandular secretions
CVS – tachycardia, postural hypotension, impair myocardial contractility
GI - constipation
Overdose = Seizures, tachycardia, elevated temperature (pyrexia), cardiac arrest.
Give an example of an SNRI
Venlafaxine
What is the mechanism of SNRIs?
Developed as SSRIs with property of noradrenaline uptake inhibition grafted on
What are the ADRs of SNRIs?
anorexia, nausea, diarrhoea
Sleep disturbance, increased BP, dry mouth, hyponatraemia
Briefly outline the progression in medication one should follow when treating depression
FIRST LINE = SSRI’s (serotonin selective reuptake inhibitor)
TCAs = Tricyclic Antidepressants
SNRI’s (serotonin/noradrenergic reuptake inhibitor)
MAOI’s (monoamine oxidase inhibitor)
Try one antidepressant for at least 6 weeks before switching to another
What are the key symptoms of schizophrenia?
Disturbances of thinking
Hallucinations = perception in the absence of an external stimulus-auditory, olfactory, visual, gustatory, tactile
Delusions = fixed false belief that it out of keeping with someone’s culture or religious beliefs
Unusual speech- thought disorder
Behavioural changes
Lack of insight
Negative symptoms
Describe the pathophysiological mechanism underlying schizophrenia
1) dopamine theory = amphetamine causes symptoms very similar to positive symptoms of schizophrenia, some evidence of increased dopamine function in schizophrenics
What are the main dopamine pathways?
Mesolimbic = emotional response and behaviour
Meso-cortical = important in arousal and mood
Nigrostriatal = key pathway damaged in Parkinson’s disease
Tuberoinfundibular = in hypothalamus and pituitary gland