Granisetron — Drug Monograph

Brand names: Kytril, Sancuso, Sustol

Drug class: Supportive Care Agent

Mechanism of Action

Selective serotonin 5-HT3 receptor antagonist. Binds with high affinity to 5-HT3 receptors on peripheral vagal nerve terminals in the gut and centrally in the chemoreceptor trigger zone. Has a higher 5-HT3 receptor selectivity and longer half-life (~9 hours IV, ~18 hours SC extended-release) than ondansetron.

FDA Indications

• Prevention of nausea and vomiting associated with initial and repeat courses of emetogenic chemotherapy (IV and PO formulations)
• Prevention of nausea and vomiting associated with radiation therapy (oral formulation)
• Prevention of CINV — transdermal patch (Sancuso) for moderately/highly emetogenic multi-day chemotherapy
• Prevention of CINV — extended-release subcutaneous injection (Sustol) for moderately and highly emetogenic chemotherapy

Common Side Effects

• Headache
• Constipation
• Asthenia/fatigue
• Diarrhea
• Injection/application site reactions (Sustol/Sancuso)

Clinical Pearl

Granisetron has a distinct advantage in multi-day chemotherapy regimens. The Sancuso transdermal patch delivers continuous granisetron exposure for up to 7 days — ideal for patients receiving 3–5 day cisplatin-based regimens. The extended-release Sustol SC injection provides sustained plasma levels for ≥5 days from a single injection, offering superior delayed CINV control compared to standard IV/PO formulations. All 5-HT3 antagonists are considered interchangeable for acute CINV at equipotent…

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