Antipsychotics

Cards (7)

  • Typical antipsychotics
    The first generation of antipsychotic drugs.
    First drug treatment for SZ.
    Dopamine antagonists (reduce the action of dopamine at the synapse).
    Created based on the initial dopamine hypothesis.
  • Atypical antipsychotics
    The second generation of antipsychotic drugs.
    Developed to improve the effectiveness of reducing positive symptoms and to reduce side effects.
    Work on dopamine receptors as well as other neurotransmitters (mainly serotonin & glutamate).
  • How do typical antipsychotics work?
    DA antagonists.
    Bind mainly to the D2 receptors in the brain.
    Strong affinity to D2 receptors- blocks dopamine by binding to receptor sites for a long period of time. Reduces the activity of the post-synaptic neuron.
    leads to an increase of DA released from the pre-synaptic neuron to begin with, until the DA levels in the vesicles are depleted, and there is a reduction of DA in the synapse.
    A reduction in DA in areas like the mesolimbic pathway through taking typical antipsychotics leads to the reduction in positive symptoms.
  • How do atypical antipsychotics work?
    Target D2 receptors but with a weaker affinity. This allows dopamine to bind to the post-synaptic receptors but at a slower rate.
    They also bind to serotonin receptors which can help to reduce the negative symptoms through the reduction of the activity of serotonin in the mesocortical pathway.
  • Typical antipsychotic example
    Chlorpromazine
    Reduces dopamine activity where it is too high, helping with symptoms such as hallucinations.
    Blocks D2 receptors in the mesolimbic dopamine pathways.
    Side effects - tiredness, blurred eyesight, dizziness, lightheadedness, uncontrollable jerky movements.
    Not common today.
  • Atypical antipsychotic example
    Risperidone
    Binds to dopamine & serotonin receptors.
    Few side effects.
    Commonly used.
  • Strengths of antipsychotics
    Revolutionised treatment and care of SZ patients, allowing them to live a relatively normal life. Saves cost of hospitalisation.
    Supporting evidence - Davis et al found typical drugs have long term benefits for 55-60% of patients.