Partial agonist for 5-HT1A, D2, D3; high affinity for D2 and D3 describes which agent?

Partial agonist for 5-HT1A, D2, D3; high affinity for D2 and D3 describes which agent?

• A. Aripiprazole
• B. Brexpiprazole
• C. Cariprazine
• D. Clozapine

Answer: (B)

The mechanism being tested is the receptor profile of atypical antipsychotics, specifically drugs that act as partial agonists at dopamine D2 and serotonin 5-HT1A receptors and that have notable affinity for D2 and D3 receptors. This combination can provide antipsychotic effects while limiting extrapyramidal symptoms and prolactin elevation, and the D3 interaction can influence mood and negative symptoms. Brexpiprazole fits this description well. It acts as a partial agonist at both D2 and 5-HT1A receptors, and it has high affinity for D2 and D3 receptors, which helps modulate dopaminergic signaling where it’s most needed. Its action on 5-HT2A also contributes to a favorable side-effect profile and can help with negative symptoms and anxiety. Aripiprazole also has D2 and 5-HT1A partial agonism, but brexpiprazole’s binding profile includes strong D2/D3 affinity and a slightly different intrinsic activity, which tends to translate into a distinct clinical balance of efficacy and tolerability. Cariprazine is more D3-preferring in its dopaminergic activity, emphasizing D3 engagement, and clozapine is not a partial agonist at D2/D3, instead behaving as a broad antagonist at multiple targets.

The mechanism being tested is the receptor profile of atypical antipsychotics, specifically drugs that act as partial agonists at dopamine D2 and serotonin 5-HT1A receptors and that have notable affinity for D2 and D3 receptors. This combination can provide antipsychotic effects while limiting extrapyramidal symptoms and prolactin elevation, and the D3 interaction can influence mood and negative symptoms.

Brexpiprazole fits this description well. It acts as a partial agonist at both D2 and 5-HT1A receptors, and it has high affinity for D2 and D3 receptors, which helps modulate dopaminergic signaling where it’s most needed. Its action on 5-HT2A also contributes to a favorable side-effect profile and can help with negative symptoms and anxiety.

Aripiprazole also has D2 and 5-HT1A partial agonism, but brexpiprazole’s binding profile includes strong D2/D3 affinity and a slightly different intrinsic activity, which tends to translate into a distinct clinical balance of efficacy and tolerability. Cariprazine is more D3-preferring in its dopaminergic activity, emphasizing D3 engagement, and clozapine is not a partial agonist at D2/D3, instead behaving as a broad antagonist at multiple targets.