What is the evidence for the use of Ondansetron (ondansetron) in the treatment of acute gastroenteritis in adults?

From the Guidelines

Ondansetron can be considered for the treatment of acute gastroenteritis in adults, particularly for controlling nausea and vomiting symptoms, once the patient is adequately hydrated, as stated in the 2017 Infectious Diseases Society of America clinical practice guidelines 1.

Key Points

• The use of ondansetron in adults with acute gastroenteritis is supported by moderate evidence, primarily for its antiemetic properties in managing nausea and vomiting.
• The typical dosing of ondansetron is 4-8 mg orally every 8 hours as needed, with the orally disintegrating tablet (ODT) formulation being useful for patients with difficulty in oral intake.
• Treatment duration is usually short-term, lasting 1-2 days or until symptoms resolve.
• Ondansetron works by blocking serotonin (5-HT3) receptors, reducing the nausea and vomiting reflex, but it does not treat the underlying cause of gastroenteritis or reduce the duration of illness.
• It should be used alongside appropriate rehydration therapy, as emphasized in the guidelines 1.

Considerations

• Common side effects of ondansetron include headache, constipation, and occasionally QT interval prolongation, necessitating caution in patients with cardiac conditions or electrolyte abnormalities.
• The guidelines suggest that ancillary treatment with antimotility, antinausea, or antiemetic agents can be considered once the patient is adequately hydrated, but their use is not a substitute for fluid and electrolyte therapy 1.
• While ondansetron can help manage symptoms and potentially reduce the need for IV fluids or hospitalization, its primary role is in symptom management rather than altering the course of the disease.
• The evidence for ondansetron's use in adults is not as robust as in pediatric populations, where it has been shown to reduce vomiting and the need for hospitalization for rehydration 1.

From the Research

Evidence for Ondansetron in Acute Gastroenteritis

• The use of ondansetron in the treatment of acute gastroenteritis in adults has been studied in several clinical trials 2, 3.
• A randomized clinical trial published in JAMA Network Open in 2019 found that a long-acting bimodal release oral ondansetron tablet was effective in decreasing gastroenteritis-related vomiting and eliminating the need for intravenous therapy for 24 hours after administration 2.
• The study included 321 patients with a mean age of 29 years and found that treatment success was observed in 65.6% of patients in the bimodal release ondansetron group compared to 54.3% in the placebo group 2.
• Another study published in Current Opinion in Infectious Diseases in 2020 found that single-dose ondansetron administration in emergency departments safely reduces intravenous fluid administration and hospitalization rates 3.
• The study also noted that intravenous ondansetron administration and multiple-dose use should be avoided, and that a bimodal release ondansetron formulation may improve outcomes in adolescents and adults with acute gastroenteritis 3.

Mechanism of Action and Benefits

• Ondansetron is a highly potent antiemetic drug that is effective in preventing nausea and vomiting 4.
• The use of ondansetron in acute gastroenteritis may facilitate oral rehydration therapy (ORT) and minimize the need for intravenous hydration and hospitalization 5, 4.
• Ondansetron has been shown to be safe and well-tolerated in patients with acute gastroenteritis, with few adverse effects reported 2, 5.

Clinical Applications

• Ondansetron may be considered as a first-line antiemetic in situations where vomiting hinders ORT 5.
• The use of ondansetron in emergency departments may improve outcomes and reduce healthcare costs by reducing the need for intravenous therapy and hospitalization 2, 3.
• A discharge action plan employing single-dose home use of ondansetron may be effective in managing ongoing nausea and vomiting in patients with acute gastroenteritis 6.