A 55-year-old hypertensive man on hydrochlorothiazide has a documented QTc of 520 ms and requires initiation of an antipsychotic. Which agent should be avoided because of its pronounced QT-prolonging effect?
- A Risperidone
- B Ziprasidone ✓
- C Olanzapine
- D Aripiprazole
Correct answer: B. Ziprasidone
Explanation
Ziprasidone produces the greatest QTc prolongation among commonly used atypical antipsychotics and is contraindicated with other QT-prolonging drugs, recent myocardial infarction or uncompensated heart failure. Hypokalemia from thiazide therapy further amplifies torsadogenic risk. Aripiprazole and olanzapine have minimal QT effects, and risperidone's effect is modest compared with ziprasidone.
Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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