ATC Group: N05AX Other antipsychotics

It has been proposed that aripiprazole’s efficacy in schizophrenia and Bipolar I Disorder is mediated through a combination of partial agonism at dopamine D₂ and serotonin 5-HT_1A receptors and antagonism of serotonin 5-HT_2A receptors.

Brexpiprazole is an atypical antipsychotic agent. The pharmacology of brexpiprazole is believed to be mediated by a modulatory activity at the serotonin and dopamine systems that combines partial agonist activity at serotonergic 5-HT_1A and at dopaminergic D₂ receptors with antagonist activity at serotonergic 5-HT_2A receptors, with similar high affinities at all of these receptors.

Cariprazine is indicated for the treatment of schizophrenia in adult patients. The mechanism of action of cariprazine is not fully known. However the therapeutic effect of cariprazine may be mediated through a combination of partial agonist activity at dopamine D₃, D₂ (Ki values of 0.085-0.3 nM versus 0.49-0.71 nM respectively) and serotonin 5-HT_1A receptors (Ki values of 1.4-2.6 nM), and antagonist activity at serotonin 5-HT_2B, 5-HT_2A and histamine H₁ receptors (Ki values of 0.58-1.1 nM, 18.8 nM and 23.3 nM, respectively).

The mechanism of action of iloperidone in schizophrenia and bipolar I disorder is unknown. However, the efficacy of iloperidone could be mediated through a combination of dopamine type 2 (D₂) and serotonin type 2 (5-HT₂) antagonism. Iloperidone forms an active metabolite, P88, that has an in vitro receptor binding profile similar to the parent drug.

Paliperidone is a selective blocking agent of monoamine effects, whose pharmacological properties are different from that of traditional neuroleptics. Even though paliperidone is a strong D₂-antagonist, which is believed to relieve the positive symptoms of schizophrenia, it causes less catalepsy and decreases motor functions to a lesser extent than traditional neuroleptics.

Pimavanserin is an atypical antipsychotic indicated for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis. The mechanism of action of is unclear. However, the effect of pimavanserin could be mediated through a combination of inverse agonist and antagonist activity at serotonin 5-HT_2A receptors and to a lesser extent at serotonin 5-HT_2C receptors.

Risperidone is a selective monoaminergic antagonist with unique properties. Although risperidone is a potent D₂ antagonist, which is considered to improve the positive symptoms of schizophrenia, it causes less depression of motor activity and induction of catalepsy than classical antipsychotics.