S13) Psychopharmacology Flashcards
What causes depression?
- Theory – low serotonin production in brain
- Additional – environmental triggers e.g. death, divorce, trauma
- Genetic susceptibility
How does depression present?
- Mental – low mood, anhedonia, fatigue, sleep disturbance, suicidal thoughts
- Physical – pain, irritable bowel, loss of appetite, low libido, weight loss/gain
How does one diagnose / determine the severity of depression?
Beck’s depression scale:
- Mild / moderate / severe?
- Are activities of daily living affected?
How does one manage a patient presenting with depression?
- Assess suicide risk?
- Mental health act assessment/sectioning
- Psychological therapy (first line) e.g. counselling/cognitive behavioural therapy = first line
- Antidepressants (first line) e.g. SSRI’s
What are the indications for antidepressants?
- Depression
- Anxiety
- Neuropathic pain
Provide some examples of antidepressants
- Serotonin selective reuptake inhibitor (first line)
- Tricyclic antidepressants
- Serotonin/noradrenergic reuptake inhibitor
- Monoamine oxidase inhibitor
What are the principles of prescribing for antidepressants?
- Try one antidepressant for at least 6 weeks before switching to another
- Even if feeling better, continue for at least a year to reduce relapse risk
Provide two examples of SSRIs
- Citalopram
- Fluoxetine
In three steps, describe the mechanism of action of SSRIs
⇒ Limits reabsorption of serotonin into the presynaptic cell (neurone)
⇒ Increases level of serotonin in the synaptic cleft available to bind to the postsynaptic receptor
⇒ Carries on action potential
What are the common side effects of SSRIs?
- Nausea
- Sexual dysfunction
- Insomnia
What is serotonin syndrome?
Serotonin Syndrome is a life threatening presentation which occurs within a few weeks of initiating SSRIs or when 2 used at once
What is the presentation of serotonin syndrome?
- Tachycardia
- Sweating
- Dilated pupils
- Myoclonus
- Hyperreflexia
- Hyperthermia
What are the complications of serotonin syndrome?
- Seizures
- Muscle breakdown
- Complications of hyperthermia
Provide an example of a TCA
Amitriptyline
What are the indications of TCAs?
- Depression
- Neuropathic pain
What is the mechanism of action of TCAs?
Mechanism of action – act largely as SNRIs (serotonin noradrenaline reuptake inhibitors)
What are the common side effects of TCAs?
Due to anti muscarinic action:
- Dry mouth/nose
- Blurry vision
- Constipation
- Urinary retention
- Cognitive and/or memory impairment
What are the cardiotoxic and neurotoxic adverse drug reactions of TCAs?
- Cardiotoxic: can result in life threatening inhibitors
- Neurotoxic: seizures, hallucinations, delirium and coma
What are the two types of antipsychotics?
- Typical (old generations - 1950s)
- Atypical (new generation)
Describe the mechanism of action of typical antipsychotics
- Typical antipsychotics act predominantly as dopamine antagonists
- More likely to cause extrapyramidal side effects
Provide two examples of typical antipsychotics
- Haloperidol
- Chlorpromazine
Describe the mechanism of action of atypical antipsychotics
- Atypical antipsychotics act at serotonin (5HT2) receptors as agonists as well as dopamine antagonists
- More effective in reducing negative symptoms of schizophrenia
Provide four examples of atypical antipsychotics
- Risperidone
- Quetiapine
- Aripiprazole
- Clozapine
- Olanzapine
Identify and describe the four main side effects arising from treatment with antipsychotics
- Anticholinergic – dry mouth, urinary retention, blurred
- Serotonergic – nausea, sexual dysfunction, insomnia (also due to anti-adrenergic)
- Metabolic syndrome – increased blood glucose, obesity, increased cardiovascular risk
- Antidopaminergic – extrapyramidal side effects
What is a specific side effects of clozapine?
Clozapine can cause agranulocytosis resulting in neutropenia (requires FBC monitoring)
What are extrapyramidal side effects?
- Extrapyramidal side effects are side effects caused by all dopamine antagonists
- They are more prominent in the typical antipsychotics as these largely act on D2 receptors
Identify and describe four extrapyramidal side effects
- Dystonia – sustained muscle contraction resulting in abnormal fixed posture
- Akathisia – internal feeling of restlessness
- Tardive dyskinesia – abnormal, involuntary, repetitive movements e.g. grimacing, sticking out the tongue or smacking of the lips
- Pseudo-parkinsonism – rigidity, tremor and increased tone
What is neuroleptic malignant syndrome?
Neuroleptic malignant syndrome is life threatening reaction within 2 weeks of initiating antipsychotics characterised by fever, altered mental status, muscle rigidity and autonomic dysfunction (tachycardia, labile BP, flushing)
Provide three examples of anxiolytics (benzodiazepines)
- Lorazepam
- Diazepam
- Midazolam
What are the indications for anxiolytics?
- Anxiety (short term – orally)
- Anticonvulsant in acute seizure (IM, IV, buccal)
- Sedative
In two steps, describe the mechanism of action of anxiolytics
⇒ Potentiate the action of GABA (main inhibitory neurone)
⇒ Increase opening of chloride channels – hyperpolarized membrane
