As oncology nurses, we must have a solid understanding of and a certain comfort level with the use of antiemetics. It seems easy to get stuck in a routine that revolves around one or two drugs for all of our patients. However, antiemetic regimens need to be just as individualized for patients as their chemotherapy regimens.

Perhaps one of the most important lessons about the treatment of nausea is the need to identify the type and cause of nausea, which then directs the treatment. Here is my attempt at simplifying the process.

Types of Chemotherapy-Induced Nausea and Vomiting (CINV)

  • Acute
  • Delayed
  • Anticipatory
  • Breakthrough

Nausea and vomiting can also be caused by the following.

  • Pain
  • Electrolyte abnormalities (e.g., hypercalcemia, hyponatremia)
  • Central nervous system source (e.g., disease-, motion-related/vestibular)
  • Gastrointestinal-related (e.g., constipation, disease-related)
  • Radiation

Once the cause of the nausea has been determined, practitioners can determine the best strategy to reduce nausea and vomiting symptoms using antiemetics from the following classes.

Seratonin (5HT3) Blockers

  • Examples: ondansetron, granisetron, palonsetron, and tropisetron
  • Can cause headache, constipation, and QTc prolongation

Dopamine Antagonists 

  • Examples: metoclopramide, prochloperazine, promethazine, and haloperidol
  • Best for delayed and breakthrough CINV

Muscarinic Receptor Antagonist

  • Example: scopalamine patch
  • Best for nausea and vomiting caused by dizziness or motion

Histamine Receptor Antagonist

  • Example: diphenhydramine
  • Used to reduce extrapyramidal symptoms
  • Can cause sedation, dry mouth, and constipation

Neurokinin-1 (NK-1) Receptor Antagonist

  • Example: aprepitant
  • Best for prevention of delayed CINV with highly emetogenic therapy


  • Examples: dexamethasone and methylprednisolone
  • Best as part of combination therapy with acute or delayed CINV or as single agents for breakthrough nausea and vomiting
  • Should be used short-term because of the large side-effect profile (e.g., insomnia, hyperglycemia, agitation).


  • Example: lorazepam
  • Anxiolytic and amnesic effects
  • Best in anticipatory CINV


  • Examples: dronabinol and nabilone
  • Mechanism of action unknown
  • Avoid in elderly; can cause hallucinations
  • Best for refractory CINV and appetite stimulation

As a reminder, ASCO recommends the following prophylaxis treatment regimens for acute CINV.

  • High emetogenicity (>90%): three-drug therapy using aprepitant, a 5HT3-blocker, and dexamethasone
  • Moderate emetogenicity (30%–90%): If anthracycline and cyclophosphamide combination, use three-drug therapy as above; otherwise, 5HT3-antagonist plus dexamethasone
  • Low emetogenicity (10%–30%): dexamethasone as a single agent
  • No prophylaxis is recommended for minimal emetogenicity (<10%).