Valbenazine, approved for the treatment of tardive dyskinesia, acts through which mechanism?
- A Reversible inhibition of the vesicular monoamine transporter 2 (VMAT2) ✓
- B Selective D2 receptor antagonism limited to the mesolimbic pathway
- C Partial agonism at dopamine D3 receptors
- D Blockade of muscarinic M4 receptors in the striatum
Correct answer: A. Reversible inhibition of the vesicular monoamine transporter 2 (VMAT2)
Explanation
Valbenazine is a reversible, highly selective VMAT2 inhibitor that reduces packaging of dopamine into synaptic vesicles, thereby decreasing dopamine release and dampening the involuntary movements of tardive dyskinesia. Deutetrabenazine shares this target. Conventional D2 blockade worsens parkinsonian symptoms rather than treating dyskinesia, and no antipsychotic acts selectively on one dopaminergic pathway, ruling out option B.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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