What is the preferred antiemetic (anti-emetic) choice for patients with malignancy (cancer)?

From the Guidelines

The preferred antiemetic choice for patients with malignancy is a three-drug combination of a 5-HT3 serotonin receptor antagonist, dexamethasone, and aprepitant for high emetic risk, and a two-drug combination of a 5-HT3 receptor serotonin antagonist and dexamethasone for moderate emetic risk. This recommendation is based on the American Society of Clinical Oncology guideline for antiemetics in oncology, updated in 2006 1.

Emetic Risk Categories

The choice of antiemetic therapy depends on the emetogenic potential of the chemotherapy regimen, which is categorized into four levels: high (90%), moderate (30% to 90%), low (10% to 30%), and minimal (less than 10%) emetic risk.

• High emetic risk: The three-drug combination of a 5-HT3 serotonin receptor antagonist, dexamethasone, and aprepitant is recommended before chemotherapy 1.
• Moderate emetic risk: The three-drug combination of a 5-HT3 receptor serotonin antagonist, dexamethasone, and aprepitant is recommended for patients receiving AC, while the two-drug combination of a 5-HT3 receptor serotonin antagonist and dexamethasone is recommended for other moderate emetic risk chemotherapies 1.
• Low emetic risk: Dexamethasone 8 mg is suggested, with no routine preventive use of antiemetics for delayed emesis 1.
• Minimal emetic risk: No antiemetic should be administered routinely before or after chemotherapy 1.

Antiemetic Agents

The guideline recommends that 5-HT3 serotonin receptor antagonists be administered with dexamethasone and aprepitant in patients receiving chemotherapy of high emetic risk and in patients receiving AC 1. Lorazepam and diphenhydramine are useful adjuncts to antiemetic drugs, but are not recommended as single agents 1.

Individualized Antiemetic Selection

Patient-specific factors like prior chemotherapy experience, motion sickness history, and pregnancy status should guide individualized antiemetic selection. These medications work through different mechanisms: 5-HT3 antagonists block serotonin receptors in the gut and brain, NK1 antagonists block substance P, dexamethasone reduces inflammation 1.

From the FDA Drug Label

Aprepitant capsules are indicated • in combination with other antiemetic agents, in patients 12 years of age and older for prevention of: • acute and delayed nausea and vomiting associated with initial and repeat courses of highly emetogenic cancer chemotherapy (HEC) including high-dose cisplatin (1. 1) • nausea and vomiting associated with initial and repeat courses of moderately emetogenic cancer chemotherapy (MEC) (1.1)

The preferred antiemetic choice for patients with malignancy (cancer) is aprepitant in combination with other antiemetic agents 2, 2.

• Aprepitant is used for the prevention of acute and delayed nausea and vomiting associated with highly emetogenic cancer chemotherapy (HEC) and moderately emetogenic cancer chemotherapy (MEC).
• It is recommended to administer aprepitant in combination with other antiemetic agents, such as ondansetron and dexamethasone, for the prevention of chemotherapy-induced nausea and vomiting (CINV) 2, 2.

From the Research

Antiemetic Choices for Cancer Patients

• The 5-HT3 receptor antagonists, such as ondansetron, granisetron, and dolasetron, are widely used for chemotherapy-induced nausea and vomiting 3.
• These agents are considered a standard part of care for moderately- and highly-emetogenic chemotherapy in combination with corticosteroids 3.
• Comparative trials between the three agents have shown no clinically important differences in outcome and they should be considered clinically equivalent 3.

Combination Therapy with Corticosteroids

• The use of dexamethasone with 5-HT3-receptor antagonists has been shown to improve control of acute emetic episodes 4.
• Combination therapy with dexamethasone is rational given the different mechanisms of action, low incidence of adverse effects, and potential synergistic effect with 5-HT3-receptor antagonists 4.
• Complete response (no nausea and vomiting) was achieved in 58% to 92% of patients receiving a corticosteroid plus a 5-HT3-receptor antagonist, compared with 39% to 79% of patients receiving a 5-HT3-receptor antagonist alone 4.

Optimal Use of 5-HT3-Receptor Antagonists

• Effective antiemetic therapy is crucial for patients undergoing chemotherapy or radiotherapy for cancer 5.
• The 5-HT3-receptor antagonists are widely prescribed to patients receiving cancer treatment, but not always appropriately 5.
• Guidelines suggest that, used at appropriate doses, the 5-HT3 receptor antagonists demonstrate equivalent efficacy and safety 6.
• The dose of antiemetic agent administered should be sufficiently high to ensure good emesis control across the whole patient population 6.

Efficacy of Oral Ondansetron

• Oral ondansetron has been shown to be an effective and well-tolerated antiemetic treatment in the management of cancer patients receiving ambulatory cyclophosphamide-based chemotherapy 7.
• All ondansetron dose groups were superior to the placebo control group for all measured efficacy parameters (complete response, number of emetic episodes, therapeutic failures, need of rescue antiemetics) 7.