From the Guidelines
Antiemetics are medications used to prevent or treat nausea and vomiting, and the main classes include dopamine antagonists, serotonin (5-HT3) antagonists, neurokinin-1 receptor antagonists, antihistamines, anticholinergics, corticosteroids, and cannabinoids. The choice of antiemetic depends on the cause of nausea, patient characteristics, side effect profiles, and the clinical situation 1.
Types of Antiemetics
- Dopamine antagonists (prochlorperazine, metoclopramide, domperidone)
- Serotonin (5-HT3) antagonists (ondansetron, granisetron, palonosetron)
- Neurokinin-1 receptor antagonists (aprepitant, fosaprepitant)
- Antihistamines (dimenhydrinate, meclizine)
- Anticholinergics (scopolamine)
- Corticosteroids (dexamethasone)
- Cannabinoids (dronabinol, nabilone)
Clinical Recommendations
For mild nausea, antihistamines or dopamine antagonists are typically first-line. For chemotherapy-induced nausea, a combination approach is often used with 5-HT3 antagonists (ondansetron 8mg orally or 4mg IV) plus dexamethasone (8-12mg) 1. For motion sickness, scopolamine patches (1.5mg applied behind the ear 4 hours before travel) or antihistamines like meclizine (25mg) work well. For pregnancy-related nausea, vitamin B6 (10-25mg three times daily) with doxylamine (10mg) is recommended first.
Administration and Dosage
5-Hydroxytryptamine type 3 receptor (5HT3) antagonists, corticosteroids, and aprepitant are usually given once daily, while dopamine antagonists are given three or four times daily 1. The intravenous dose of ondansetron is 8 mg, granisetron is 1 mg, tropisetron is 5 mg, and dolasetron is 100 mg 1.
Special Considerations
Aprepitant is metabolized via CYP3A4, and various drugs could be influenced, so when corticosteroids are combined with aprepitant, the dose of oral/i.v. corticosteroids should be reduced to 50%/75% 1. The choice of antiemetic should be based on the clinical situation, patient characteristics, and side effect profiles 1.
From the FDA Drug Label
The recommended oral dosage of aprepitant capsules, dexamethasone, and a 5-HT3 antagonist in adults and pediatric patients 12 years of age and older who can swallow oral capsules for the prevention of nausea and vomiting associated with administration of HEC or MEC Ondansetron is a selective 5-HT 3receptor antagonist.
The different types of antiemetic medications mentioned are:
- 5-HT3 antagonists (e.g. ondansetron)
- NK1 receptor antagonists (e.g. aprepitant)
- Corticosteroids (e.g. dexamethasone) 2 3
From the Research
Types of Antiemetic Medications
The different types of antiemetic medications include:
- Steroids, such as dexamethasone 4, 5
- 5-HT3 receptor antagonists, including:
- Cannabinoids 4, 6
- Benzodiazepines 4
- Neurokinin1 receptor antagonists 4, 6, 8
- Metoclopramide 4
Combination Therapies
Combination therapies, such as the use of dexamethasone with 5-HT3-receptor antagonists, are also effective in preventing nausea and vomiting 5. The use of corticosteroids, such as dexamethasone, in combination with 5-HT3-receptor antagonists has been shown to be safe and effective in controlling chemotherapy-induced nausea and vomiting 5.
Classification of Chemotherapeutic Agents
Chemotherapeutic agents are classified into four emetic risk groups: high, moderate, low, and minimal 4. The choice of antiemetic medication depends on the emetogenic potential of the chemotherapy and the type of vomiting and nausea 4.