A 40-year-old woman receiving high-dose cytarabine for acute myeloid leukemia develops nystagmus, ataxia, and dysarthria on day 5 of therapy. The most appropriate immediate step is:

• A Continue the same dose with leucovorin rescue
• B Discontinue cytarabine, since the cerebellar toxicity may be reversible ✓
• C Switch to daunorubicin immediately
• D Administer pyridoxine and continue therapy

Explanation

Cytarabine is an S-phase-specific antimetabolite whose best-known nonhematologic dose-limiting toxicity is cerebellar dysfunction, seen especially with high-dose regimens. It is reversible if the drug is stopped early, but can become irreversible with continued exposure. Leucovorin rescues methotrexate, not cytarabine, and pyridoxine has no role here. Daunorubicin substitution is irrelevant to managing established neurotoxicity.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

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Written and medically reviewed by the StethoPrep medical team.