Dopamine 2 antagonists
Dopamine 2 receptors antagonists
Haloperidol is considered a very specific D2 antagonist, therefore it is unlikely to cause any change in prolactin levels.
Extra info: Because D2 specific antagonists can work throughout the dopaminergic system, hyperprolactemia is likely with haloperidol.
Without D2 antagonism activity, a drug is NOT an antipsychotic.
Extra info: At this point in drug development, this statement appears to be true.
The relative activity of D2 antagonism can be altered with 5-HT2A and ACH antagonism.
Extra info: The adverse effects of antipsychotics in the nigrostriatal tract can be offset with the co-administration of either 5HT2A antagonist or a muscarinic antagonist.
It is possible for antipsychotic drug to target D2 receptors in specific dopaminergic tracts.
Giving an antipsychotic to a Parkinson’s patient with hallucinations can cause a worsening of Parkinson’s symptoms.
Extra info: Unfortunately, many patients with Parkinson's will develop psychosis, therefore a slow titration of any trial with an antipsychotic is warranted.