High potency antipsychotics

Classic antipsychotics

This graphic shows the pharmacological activity of the classic antipsychotics. The receptor affinity profile of haloperidol is used as the representative of this class

of agents. Haloperidol is relatively specific for the D2 post-synaptic receptor, and as such, doesn't have many side effects associated with the blockade of other receptors. However, since the post-synaptic D2 receptor blockade is not in balance in the nigrostriatal tract, the classic antipsychotics are highly potent and are associated with significant extrapyramidal effects.

1

Haloperidol’s receptor affinity can best be described as D1, D2 > α1> 5-HT2A, M1. 

2

High potency antipsychotics are the principle etiology of acute dystonias.

3

The 5-HT2A-antagonism activity of haloperidol is insufficient to overcome the D2 antagonism.