P year‎ > ‎Psychiatry‎ > ‎

13.05.15 Psychopharmacology

EPSEs
  • Early and common
    • Parkinsonism
    • Akathesia
    • Dystonia
  • Late (years-decades), irreversible (in a third), often on withdrawal or reduced dose
    • Tardive dyskinesia

Antipsychotics
  • Receptors
    • Alpha1 NA
      • Orthostatic hypotension
      • Sedation
    • H1
      • Sedation
    • mACh
      • Reduceds EPSEs
      • Autonomic antimuscarinic effects
    • Dopamine
      • D2 receptors (Esp. D4) => Antipsychotic
  • Anti-EPSEs
    • Centrally acting antimuscarinics
      • Benzatropine, orphenadrine, procyclidine
    • May make TD worse
  • Clozapine
    • Hits D4
    • Is a potent antimuscarinic
      • But yet causes hypersalivation
      • ? Knocks out swallow reflex (so only apparent at night?)
  • Atypicals
    • All have strong anti-5-HT2 activity
    • Adverse effects:
      • Metabolic syndrome
      • Diabetes
      • Increased QT
      • Hypotension
      • Weight gain
  • Aripiprazole
    • "Dopamine stabiliser"
      • Stimulates at low [D]; Inhibits at high
    • Side-effects
      • Orthostatic hypotension
      • Seizures
      • Somnolence
    • As effective as risperidone; Not quite as good as olanzapine


Mood disorders

  • Progression
    • MAOIs
      • MAO also in GI tract => "Cheese effect" (tyramines) => Hypertensive crisis
      • Interaction with indirect sympathomimetics (epedrine etc)
    • TCAs
      • Antimuscarinic effects
      • NA uptake block => Tachycardia
      • Dangerous + no antidote
    • Atypicals
    • SSRIs
      • Half-lifes 20-30 hours, except fluoxetine (4-16 days) => Long wash-out
      • Early anxiety, agitation, nervousness
      • Beware in bipolar! => Manic symptoms
      • Increase bleeding risk cf NSAIDs, warfarin
      • P450 inhibition : Fluoxetine > Paroxetine > Citalopram/Sertraline
      • Discontinuiation syndrome: Dizziness, lethargy, nausea, headache, paraesthesia
    • SNRIs
  • Lithium has a very narrow t. window
  • Mood stabilisers are often antiepileptics (carbamazepine, valproate, lamotrigine)

Notes
  • Dopamine receptors
    • D1 = D1, D5
    • D2 = D2, D3, D4
  • Serotonin syndrome with SSRI plus MAOI/St John's Wort
  • All anticonvulsants reduce effectiveness of COCP
  • Flumazenil reverses benzo effect
  • Zopiclone is probably also addictive
  • SSRIs in anxiety disorders
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