A 55-year-old man with schizophrenia has a prolonged QT interval on ECG. Which antipsychotic should be avoided in him because of the greatest QT-prolonging potential among commonly used agents?
- A Risperidone
- B Haloperidol
- C Ziprasidone ✓
- D Olanzapine
Correct answer: C. Ziprasidone
Explanation
Ziprasidone blocks hERG potassium channels and produces the greatest degree of QT prolongation among currently used antipsychotics, warranting caution or avoidance in patients with existing QT prolongation, hypokalemia or concurrent QT-prolonging drugs. Thioridazine was historically worst and is now largely withdrawn for this reason. Haloperidol, risperidone and olanzapine carry lower, though not absent, QT risk.
Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.