Zyprexa (olanzapine) is most notably associated with which side effect?

• A. Excessive weight gain
• B. QT prolongation
• C. Corneal deposits
• D. Cataracts

Answer: (A)

Olanzapine commonly causes significant weight gain due to its effects on appetite and metabolism. It blocks receptors such as histamine H1 and serotonin 5-HT2C, which increases appetite and can lead to substantial increases in food intake. Over time, this weight gain often goes hand in hand with insulin resistance and dyslipidemia, contributing to metabolic syndrome. Because of this, weight gain is the side effect most notably associated with olanzapine among antipsychotics, and it stands out as the most clinically important long-term concern.

QT prolongation is more typical with other antipsychotics like ziprasidone and certain agents, not a hallmark of olanzapine. Corneal deposits and cataracts are not characteristic issues with olanzapine; those ocular findings are linked more to other drugs in the history of psychiatry.