Updated: 4/25/2019

Antipsychotics

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Snapshot
  • A 19-year-old male is brought into the ED by his parents.  The patient recently started college and was living in the dorms.  He struggled with school and friends and had some issues with his roommate so he moved back home.  His parents have noticed that he has become more reclusive and often stays in his room alone.  He no longer cares for himself, and has not showered in over a month.  The patient is often seen talking to himself, and when his parents ask him what he is doing he says, "It's classified information."
Overview
  • 2 classes
    • typical
      • older
      • stronger D2 receptor antagonism
        • ↑ [cAMP]
    • atypical
      • newer
      • weaker D2 receptor antagonism and stronger 5-HT2, α, and H1 antagonism
  • Targets
    • dopaminergic neurons
      • specific pathways affected include:
        • nigrostriatal (extrapyramidal motor)
        • mesolimbic (mood and reward)
        • tuberoinfundibular (prolactin release)
Typical Antipsychotics Overview
 
Typical Antipsychotics
High Potency Antipsychotics (in Descending Order)
Advantages Disadvantages Unique Features
Haloperidol
  • Fewer side effects of sedation and hypotension
  • High association with extrapyramidal symptoms
  • Able to use as long-acting depot injections
  • Can be given IM in acute situations
Fluphenazine
Perphenazine
Chlorpromazine
  • Lower frequency of extrapyramidal side effects
  • Greater incidence of anticholinergic side-effects, hypotension, sedation
  • Corneal deposits
Thioridazine 
  • Retinal deposits
  • QT prolongation
 
Typical Antipsychotics
  • Overview
    • AKA neuroleptics
    • two types
      • high potency
      • low potency
    • highly fat soluble → stored for long time in body fat
  • Drugs ("haloperidol + -azines")
    • high potency - low dose needed (more movement side-effects)
      • haloperidol
      • trifluoperazine
      • fluphenazine
    • low potency - high dose needed (more anti-cholinergic side-effects)
      • thioridazine
      • chlorpromazine
  • Clinical use
    • schizophrenia
      • primarily positive symptoms
    • psychosis
    • acute mania
      • temporary treatment because lithium has slow onset
    • Tourette's syndrome
  • Toxicity
    • high potency
      • ↑ extrapyramidal system (EPS) side effects
        • due to high affinity for D2 receptor
        • has characteristic time course
          • early onset/reversible symptoms
            • 4 hours = acute dystonia
              • spasm of face, neck, tongue, and extraocular muscles
          • intermediate-onset symptoms (days to weeks)
            • Parkinsonism
              • muscle rigidity, bradykinesia, tremor, and shuffling gait
            • akathisia
              • urge to move
          • late onset/irreversible symptoms 
            • 4 months = tardive dyskinesia 
              • involuntary, repetitive movements of facial, tongue, and neck muscles
              • anticholinergics worsen!
              • must reduce dose or switch to an atypical antipsychotic
        • can be treated with diphenhydramine or benztropine 
      • ↓ non-specific side effects (SE)
    • low potency
      • ↓ EPS SEs
      • ↑ non-specific SEs  
        • due to low affinity to D2 receptors and high concentrations needed to achieve effect
        • muscarinic receptor antagonism
          • dry mouth and constipation
          • vision problems
        • α receptor antagonism
          • orthostatic hypotension
          • sexual dysfunction
        • histamine receptor antagonism
          • sedation
        • chlorpromazine → corneal deposits
        • thioridazine → retinal deposits 
    • endocrine side effects
      • dopamine normally inhibits prolactin secretion
        • antagonism of receptor may result in hyperprolactinemia→ galactorrhea
    • neuroleptic malignant syndrome (NMS) 
 
Extrapyramidal Side Effects of High Potency D2 Blockers (Haloperidol, Fluphenazine, Perphenazine)
3 Hours: Acute Dystonia
3 Days - Weeks: Bradykinesia (Pseudo-Parkinsonism)
3 Months: Akathisia
3 Years: Tardive Dyskinesia
Emergency: Neuroleptic Malignant Syndrome
  • Muscle spams (neck, eye, diffuse)
  • Trouble swallowing
  • Symptoms of Parkinson's disease: tremors, bradykinesia, rigidity
  • Sustained feeling of motion/restlessness
  • Uncontrollable repetitive, stereotypical writhing movements, usually of the tongue
  • High fever
  • Muscle rigidity
  • Unstable vitals
  • Increased CK, K+, and WBC's
Treatment of Side Effects
  • Anticholinergic medications:(benztropine, diphenhydramine, trihexyphenidyl)
  • β-blockers
  • Benzodiazepines
  • Stop high potency D2 blockers
  • Switch to atypicals
  • Stop antipsychotic
  • IV fluids
  • Cooling
  • Dantrolene
NOTE: You can always decrease the dose or switch to a different antipsychotic – choose the drug with the side-effect profile that the patient can tolerate.
 
Atypical Antipsychotics - Overview
 
Atypical Antipsychotics
Medication Unique features and side effects
Risperidone
  • High potency
  • Usually first line
  • Hyperprolactinemia
  • Weight gain

Olanzapine

  • Severe weight gain
  • Very sedating
Ziprasidone
  • Minimal to no weight gain
  • Increased QTc
Quetiapine
  • Low potency
  • Sedating
  • Weight gain
  • Useful in bipolar depression and augmentation of major depression therapy
Lurasidone
  • Minimal weight gain
  • Useful in biploar depression
Clozapine
  • Weight gain
  • Most effective anti-psychotic
  • Decreased suicide risk
  • Agranulocytosis
  • Myocarditis
  • Sialorrhea
  • Orthostatic hypotension
  • Increased seizures
Aripiprazole
  • D2 partial agonist
  • Augmentation of major depression therapy
 
Atypical Antipsychotics
  • Drugs 
    • olanzapine
    • clozapine
    • quetiapine
    • risperidone
    • aripiprazole
    • ziprasidone
  • Mechanism
    • antagonist at 5-HT2, α, H1, and dopamine receptors
  • Clinical use
    • schizophrenia
      • both positive and negative symptoms
    • olanzapine
      • OCD
      • anxiety disorder
      • depression
      • mania
      • Tourette's syndrome
  • Toxicity
    • less EPS and anticholinergic side effects as compared to traditional antipsychotics
    • olanzapine
      • weight gain/metabolic syndrome
    • clozapine 
      • agranulocytosis
        • requires patients to have weekly WBC monitoring 
      • weight gain/metabolic syndrome
    • ziprasidone
      • prolonged QT and possible resultant torsades
    • risperidone
      • may result in hyperprolactinemia→ galactorrhea                                                   
      • EPS
 

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(M1.PY.12.41) A 58-year-old male presents to his primary care doctor with the complaint of vision changes over the last several months. The patient's past medical history is notable for schizophrenia which has been well-controlled for the last 25 years on chlorpromazine. Which of the following is likely to be seen on ophthalmoscopy? Tested Concept

QID: 101705
1

Retinitis pigmentosa

15%

(36/235)

2

Macular degeneration

11%

(27/235)

3

Glaucoma

8%

(18/235)

4

Retinal hemorrhage

3%

(6/235)

5

Corneal deposits

61%

(144/235)

M 4 B

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