Antipsychotics

Antipsychotics are mostly used to treat patients with psychosis. They are split into two groups - atypical and typical. The classification is based on the side effects. Typical (or 'first-generation') antipsychotics were the first developed and had a set of characteristic side effects. The atypical (or 'second-generation') antipsychotics, which came later, were so named because they did not cause the same characteristic side-effects to the same extent.

Yes, it's a really rubbish way to classify the drugs and the person who did it possibly needs to be sectioned...

Mode Of Action

Excess release of dopamine in the mesolimibic pathways has been linked to psychotic experiences. Antipsychotics block D₂ in all four dopamine pathways of the brain, thus stopping this excess dopamine.

Indications

• Schizophrenia
• Psychosis (secondary to depression or a physical problem)
• Delirium
• Mania (acutely)

Contraindications

Drugs

If you can find any major ones, feel free to add them

Medical Conditions

• Arrhythmias - due to prolongation of QT-complex
• Diabetes - with olanzapine due to weight gain side-effect

Side-Effects

The typical side effects mentioned above are the Extra-Pyramidal Side-Effects (EPSE):

• Tardive dyskinesia
• Dystonia
• Akasthia ('restless legs') - general feeling of restlessness which can be incredibly distressing
• Parkinsonian symptoms
  • Pill-rolling tremor (3-5Hz)
  • Cog-wheel rigidity
  • Bradykinesia
  • Stooped posture
  • Shuffling gait
  • Micrographia (small handwriting)

These side effects are caused by

Other side effects

These are the important ones, specific to atypicals:

• Weight gain - clozapine, risperidone, olanzapine, amisulpride
• Risk of diabetes - olanzapine (high risk), clozapine (moderate risk)
• Increased prolactin - amisulpride.
  • Symptoms include: galactorrhoea, amenorrhoea and infertility, sexual dysfunction
  • inhibition of dopamine in the tuberoinfindibular pathway which is linked to the pituitary - one of the four dopamine pathways
• Sedation - olanzapine

Clozapine must be specifically mentioned as it causes agranulocytosis. As such white cell count needs to be regularly monitored, measured once a week for the first few weeks.

Generic Names

Typical

• Haloperidol
• Chlorpromazine
• Flupenthixol

Atypical

• Olanzapine
• Risperidone
• Amisulpride
• Clozapine