Quetiapine Drug Class
Quetiapine (Seroquel) is an atypical antipsychotic, specifically a dibenzothiazepine derivative. 1
Pharmacological Classification
- Quetiapine belongs to the chemical class of dibenzothiazepine derivatives, distinguishing it structurally from other atypical antipsychotics 1, 2
- As an atypical antipsychotic, quetiapine functions as an antagonist at both serotonin 5-HT2 and dopamine D2 receptors 3, 2
- The drug interacts with a broad range of neurotransmitter receptors and demonstrates higher affinity for serotonin (5-HT2A) receptors relative to dopamine (D2) receptors, similar to clozapine 2
Mechanism of Action
- Quetiapine's antipsychotic effects stem from interactions at serotonin 5-HT2 and dopamine D2 receptors 3
- The antidepressant effects may be related to antagonism of 5-HT2A receptors in cortical regions, partial agonism of 5-HT1A in the prefrontal cortex with increased extracellular dopamine release, or reduced synaptic reuptake of noradrenaline through inhibition of the noradrenaline reuptake transporter by the quetiapine metabolite norquetiapine 3
- Quetiapine's pharmacological effects appear selective for the mesolimbic and mesocortical dopamine systems (responsible for therapeutic effects) while having minimal activity in the nigrostriatal dopamine system (responsible for extrapyramidal side effects) and tuberoinfundibular dopamine system (responsible for prolactin elevation) 2
FDA-Approved Indications
- Quetiapine is indicated for the treatment of schizophrenia and bipolar disorder, including bipolar depression 3
- The American Academy of Child and Adolescent Psychiatry recognizes quetiapine as one of the atypical antipsychotics approved for acute mania in adults 4, 5
Distinguishing Features from Other Atypicals
- Quetiapine is associated with placebo-level incidence of extrapyramidal symptoms (EPS) across its entire dose range, unlike risperidone 6, 7
- Unlike risperidone and amisulpride, quetiapine does not elevate plasma prolactin levels compared with placebo at any dose 6, 7
- Quetiapine has demonstrated efficacy against both positive and negative symptoms of schizophrenia, with additional benefits in improving cognitive deficits, affective symptoms, and aggression/hostility 6