Palonosetron

How it works

It selectively and with high affinity blocks serotonin 5-HT3 receptors peripherally on vagal afferents and centrally, interrupting the emetic reflex triggered by chemotherapy.

Prescribing in practice

• Like other 5-HT3 antagonists it can prolong the QT interval, so use caution in patients with risk factors for arrhythmia or on other QT-prolonging drugs.
• It has a long duration of action and is given as a single dose per chemotherapy cycle.
• Constipation and headache are common, and serotonin syndrome can occur if combined with other serotonergic agents.

Monitoring

Consider ECG monitoring of the QT interval in at-risk patients and review electrolytes, particularly potassium and magnesium.

Counselling the patient

• Tell patients that headache and constipation are common and how to manage them.
• Advise patients to report palpitations or symptoms suggesting serotonin syndrome such as agitation or tremor.

Evidence & guidelines

Palonosetron is an established option for chemotherapy-induced nausea and vomiting and features in antiemetic guidelines for moderately and highly emetogenic regimens.