Aripiprazole's ability to reduce both positive and negative symptoms of schizophrenia without weight gain is best attributed to its receptor pharmacology profile of:
- A Full D2 and D3 receptor antagonism plus 5-HT2A inverse agonism
- B D4-selective antagonism avoiding metabolic H1 blockade
- C Partial D2/D3 agonism, 5-HT2A antagonism, and partial 5-HT1A agonism with functional selectivity (biased agonism) ✓
- D Muscarinic M1 agonism restoring cholinergic-dopaminergic balance in the nucleus accumbens
Explanation
Aripiprazole is a 3rd-generation (dopamine system stabilizer) atypical antipsychotic. Its unique profile: (1) Partial D2/D3 agonism — acts as antagonist in hyperdopaminergic mesolimbic pathway (reducing positive symptoms) and as partial agonist in hypodopaminergic mesocortical pathway (addressing negative symptoms and cognition); (2) 5-HT2A antagonism — reduces extrapyramidal side effects and improves affective symptoms; (3) Partial 5-HT1A agonism — anxiolytic and antidepressant contribution. Minimal H1/M1/alpha-1 binding explains its low metabolic side-effect profile relative to olanzapine/clozapine.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.