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SSRI partial response — USMLE Step 3 MCQ

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HardPsychiatry (outpatient management)SSRI partial responseUSMLE Step 3

A 36-year-old man with schizophrenia has persistent command hallucinations and delusions after two separate adequate trials of antipsychotics from different classes, with confirmed adherence and therapeutic dosing. Substance use, mood disorder, and medical causes have been excluded. ANC is 4,200/µL, and he has no history of myocarditis or seizure. Which treatment is most appropriate?

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Correct answer: B — Initiate clozapine with baseline testing and scheduled hematologic safety monitoring

The best answer is “Initiate clozapine with baseline testing and scheduled hematologic safety monitoring”. Failure of two adequate antipsychotic trials establishes treatment-resistant schizophrenia, for which clozapine is the evidence-based treatment rather than serial standard-agent switching, combination treatment, psychotherapy alone, or ECT augmentation before clozapine. Baseline ANC is adequate. Titration must account for orthostasis, seizure, myocarditis, constipation, and metabolic effects, and ANC monitoring remains necessary even though the FDA removed the separate REMS reporting requirement in 2025.

Reference: FDA Clozapine REMS Removal Safety Communication: https://www.fda.gov/drugs/drug-safety-and-availability/fda-removes-risk-evaluation-and-mitigation-strategy-rems-program-antipsychotic-drug-clozapine