3.2.2 Extrapyramidal side effects: introduction
The use of antipsychotics is associated with movement disorders described collectively as extrapyramidal side effects; they comprise:
- Acute dystonia
- Akathisia
- Drug-induced parkinsonism
- Tardive dyskinesia
The ‘extrapyramidal system’ is responsible for involuntary reflexes and coordination of movement. It is distinguished from ‘pyramidal pathways’, which control impulses for voluntary movement originating in the motor cortex and are not directly inhibited by antipsychotics.
The extrapyramidal effects of antipsychotics result from antagonism of dopamine D2 receptors in the nigrostriatal pathway.