S13 Drugs used in Psychiatric Disease Flashcards
Outline the presentation of a patient with depression?
Patient has symptoms continually for 2 weeks and consists of core symptoms (Low mood, decreased energy and anhedonia – lack of enjoyment), Biological symptoms (e.g weight loss, less sleep).
Outline the pathophysiology (possible) of depression
Monoamine neurotransmitters (NA or serotonin) are deficient. Depletion of receptors for the monoamine transmitters at the post-synaptic membrane, despite adequate neurotransmitter levels
How is depression diagnosed?
Becks depression scale
Outline the mechanism of SSRIs
First-line therapy. E.g fluoxetine, citalopram, sertraline.
Inhibit reuptake of ST into presynaptic cell so more is left in cleft to bind to receptor
Outline the PK and ADRs of SSRIs
PK: metabolised in liver
ADRs: insomnia, nausea, and diarrhoea, rare ones of mania, serotonin syndrome
What is serotonin syndrome?
Life-threatening presentation when first using SSRIs; tachycardia, sweating
Outline the mechanism of TCAs
E.g Amitriptyline, Lofepramine
Act largely as SNRIs (serotonin and noradrenaline reuptake inhibitors) at presynaptic membrane so more is left in cleft to bind to receptor
Outline the PK and ADRs of TCAs
PK: metabolised by liver
ADRs: dry mouth, blurry vision, constipation
Outline the mechanism of SNRIs
E.g Venlafaxine
Inhibit serotonin and NA reuptake at presynaptic membrane so more is left in cleft to bind to receptor
Outline the ADRs of SNRIs
Same as SSRIs, as well as sleep disturbances, increased BP, dry mouth
Outline the pathophysiology of schizophrenia
Excess of dopamine release from the Brain.
Meso-limbic pathway is overactive
Meso-cortical pathway is underactive
Outline the mechanism of typical anti-psychotics
E.g Haloperidol, chlorpromazine
Act as D2-antagonists but effect CNS symptoms, so cause extra-pyramidal symptoms e.g pseudo-parkinsonism, dystonia, akathisia (restlessness).
Outline the ADRs of typical anti-psychotic
Postural hypotension, cardiac toxicity, neuroleptic malignant syndrome (life-threatening reaction when first using antipsychotics; fever, muscle rigidity)
Outline the mechanism of atypical anti-psychotics
E.g Risperidone, olanzapine.
ST receptor agonists, also D2-antagonists that produce less extra-pyramidal signs
Outline the ADRs of Atypical Anti-Psychotics
Weight gain (Olanzapine), increased prolactin secretion (Ripseridone), extra-pyramidal side effects at high dose
What is anxiety and its presentation?
Fear out of proportion of the situation.
Symptoms: avoidance, light-headedness, hot and cold flushes.
First line treatment is non-pharmacological, commonly CBT, then anxiolytics.
Outline the mechanism of benzodiazepines in anxiety
Increase the action of GABA (main inhibitory neurone), and increase opening of chloride channels
Outline the ADRs of benzodiazepines
Drowsiness, dizziness, cleft lip if used in pregnancy.
Should only be used in short term as people become dependent (withdrawal symptoms) and develop tolerance (need higher dose)
What do we use to treat benzodiazepine overdose?
Flumazenil
What is bipolar disorder?
Episodes of both depression and mania
What is the treatment for bipolar disorder and its mechanism?
Lithium
Li can increase 5-HT and attenuate effects of certain neurotransmitters on their receptors
Outline the ADRs of lithium
Memory problems, tremor, and acts as a nephrotoxin.
Outline the mediation prescribed in dementia
Acetylcholinesterase Inhibitors: Donepezil, Galantamine.
NMDA antagonist: Memantine
