From the Guidelines
Ondansetron is not routinely recommended as first-line treatment for viral gastroenteritis in adults, though it may be considered in cases of severe, intractable vomiting. When used, the typical adult dosage is 4-8 mg orally every 8 hours as needed, with a maximum daily dose of 24 mg, as suggested by the 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea 1.
Key Considerations
- Ondansetron works by blocking serotonin receptors in the chemoreceptor trigger zone of the brain, reducing the vomiting reflex 1.
- However, for most cases of viral gastroenteritis, the primary treatment should focus on oral rehydration therapy with electrolyte solutions, as the condition is typically self-limiting within 1-3 days.
- Ondansetron should be used cautiously in patients with cardiac conditions or electrolyte abnormalities due to potential QT interval prolongation.
- Common side effects include headache, constipation, and dizziness, as noted in the guidelines 1.
- It's essential to remember that treating the symptoms with ondansetron does not address the underlying viral infection or the need for adequate hydration, which remains the cornerstone of gastroenteritis management.
Additional Guidance
- A recommendation cannot be made for the routine use of antiemetic agents for acute gastroenteritis in adults, according to the guidelines 1.
- Antinausea and antiemetic (eg, ondansetron) may be given to facilitate tolerance of oral rehydration in children >4 years of age and in adolescents with acute gastroenteritis associated with vomiting (weak, moderate) 1.
- Patients should be advised about medications with the potential to increase the risk of complications from diarrhea, particularly antidiarrheal and antimicrobial agents 1.
From the Research
Role of Ondansetron in Treating Viral Gastroenteritis in Adults
- Ondansetron, an antagonist of the type 3 serotonin receptor, has been shown to reduce the rate of vomiting and improve the tolerance of oral rehydration in patients with gastroenteritis 2, 3.
- A randomized clinical trial found that a long-acting bimodal release oral ondansetron tablet was an effective antiemetic among adolescents and adults with moderate to severe vomiting from acute gastroenteritis, reducing the need for intravenous therapy and emergency department care 4.
- The use of ondansetron in adults with viral gastroenteritis has been studied, and the results suggest that it can be an effective treatment for reducing vomiting and improving oral rehydration 4.
- The benefits of ondansetron in treating viral gastroenteritis in adults include:
- Reduced vomiting
- Improved oral rehydration
- Reduced need for intravenous therapy
- Reduced need for emergency department care
- The studies suggest that ondansetron can be used as a first-line treatment for viral gastroenteritis in adults, especially in cases where vomiting is severe and oral rehydration is difficult 3, 4.
- However, it is essential to note that the majority of the studies were conducted in pediatric populations, and more research is needed to confirm the efficacy and safety of ondansetron in adult populations 2, 3, 5, 6.