How Postoperative Nausea and Vomiting Medications Work

Postoperative nausea and vomiting (PONV) is a common complication after surgery, affecting up to 70% of patients. The pathophysiology involves multiple neurotransmitter systems, including serotonin (5-HT), dopamine, and substance P.

Gold Standard: Ondansetron (5-HT3 antagonist)

Ondansetron is the gold standard for preventing PONV. It works by selectively blocking 5-HT3 receptors in the chemoreceptor trigger zone of the central nervous system, thereby reducing nausea and vomiting.

Alternatives: Dopamine Antagonists and NK1 Receptor Antagonists

• Metoclopramide (Dopamine antagonist): Blocks dopamine receptors in the chemoreceptor trigger zone, reducing nausea and vomiting.
• Aprepitant (NK1 receptor antagonist) and Fosaprepitant: Block substance P release from terminals of sensory neurons, further reducing nausea and vomiting.

Key Considerations

When selecting a medication for PONV prevention, consider the patient's risk factors, such as previous history of PONV, anxiety or stress, pain management with opioids, and female gender. A combination of medications may be used to achieve optimal results.