Ondansetron, marketed under the brand name Zofran®, is commonly used to control nausea and vomiting. However, its use is limited in certain cases, notably in children suffering from gastroenteritis with moderate to severe diarrhea, due to its potential side effect of aggravating diarrhea. It is essential to understand dosage and side effects before use.
Understanding ondansetron and its role
Ondansetron is a selective serotonin antagonist (a chemical produced by the body) which plays a central role in controlling nausea and vomiting. It is particularly used in the treatment of nausea and vomiting associated with chemotherapy, radiotherapy or surgery.
Its action is to attenuate the effects of serotonin, resulting in a significant reduction in the symptoms of nausea and vomiting. In gastroenteritis in children, it is often prescribed as a single oral dose, which is generally effective and safe for improving the success of oral rehydration.
The different uses of ondansetron
Use of ondansetron for gastroenteritis
Ondansetron is a prescription antiemetic (antinauseant), particularly useful for treating acute nausea and vomiting associated with gastroenteritis. Several studies have demonstrated its efficacy in infants and children, contributing to successful oral rehydration. A single dose is often sufficient to control symptoms.
In the context of gastroenteritis, its role is to enhance the success of oral rehydration, a key element in the treatment of this disease, by reducing nausea and vomiting to help retain ingested fluids. However, it should be stressed that ondansetron is not used systematically, and is reserved for more severe cases of nausea and vomiting. It does not replace the need for adequate rehydration and other appropriate care measures.
Other indications for ondansetron use
Ondansetron is also used in postoperative treatment to prevent and manage the nausea and vomiting that may occur after surgery. In addition, it can be prescribed for the treatment of nausea and vomiting induced by radiotherapy or chemotherapy.
Ondansetron can also be used to treat certain forms of migraine. Its antagonistic effect on serotonin receptors can help alleviate the symptoms associated with these severe headaches, such as nausea.
- Prevention of post-operative nausea and vomiting
- Treatment of nausea and vomiting induced by radiotherapy and chemotherapy
- Treatment of nausea and vomiting associated with migraines
However, the use of ondansetron for these indications should always be prescribed by a healthcare professional to avoid undesirable drug interactions or overdosage.
Ondansetron's efficacy in the treatment of gastroenteritis
Ondansetron's action on gastroenteritis symptoms
Ondansetron plays a role in reducing the symptoms of gastroenteritis by blocking the action of serotonin, a neurotransmitter which, when released in excess, can lead to vomiting.
By decreasing serotonin activity, ondansetron helps reduce nausea and vomiting, two of the most common symptoms of gastroenteritis. It can also help prevent dehydration, a major risk associated with this disease given its symptoms.
It should be noted that ondansetron does not directly treat the cause of gastroenteritis, but helps manage its symptoms, thus facilitating recovery.
In moderate to severe gastroenteritis, ondansetron is generally administered as soon as acute vomiting appears. Its rapid onset of action effectively controls vomiting, facilitating oral rehydration. However, ondansetron should not be used as a first-line treatment for mild to moderate gastroenteritis. It should be reserved for cases where symptoms are severe or when other treatments have not been effective.
Results of studies on the use of ondansetron for gastroenteritis
Several studies have been conducted on the efficacy of ondansetron in the treatment of gastroenteritis. One study showed that ondansetron significantly reduced vomiting in children with this disease (A Cheng; Canadian Paediatric Society. Updated by Marie-Joëlle Doré-Bergeron and Laurel Chauvin-Kimoff, 2018). An improvement in clinical outcomes was also observed, with a reduction in intravenous rehydration and patient hospitalization.
Other research has compared the efficacy of ondansetron with other treatments. One study compared the efficacy of a single intravenous dose of ondansetron with that of metoclopramide, another antiemetic, in the treatment of persistent vomiting in uncomplicated gastroenteritis. The efficacy of ondansetron appeared to be superior.
How to administer ondansetron
Ondansetron dosage for gastroenteritis
The exact dose of ondansetron should always be determined by a healthcare professional. In children, the dose may vary according to weight. Ondansetron may be taken with or without food. Adherence to the dosage indicated on the label is crucial to ensure treatment efficacy and limit side effects.
Different forms of ondansetron administration
Ondansetron can be administered in a variety of ways, depending on the patient's condition and therapeutic indication. It is available in tablet form, to be swallowed with water. Another oral form is the orodispersible tablet, which dissolves rapidly on the tongue, or the liquid solution.
For cases requiring faster action, ondansetron can be administered by injection. This form is particularly recommended for the prevention or treatment of post-operative nausea and vomiting.
It is essential to follow the dosage prescribed by your healthcare professional to avoid any risk of overdose. If you have any questions about your prescribed dosage of ondansetron, your pharmacist can help.
Ondansetron side effects and contraindications
Common side effects
The most common side effects of ondansetron include :
- Headache: Headache may occur.
- Gastrointestinal disorders: Constipation is a possible side effect, as is diarrhea.
- Other symptoms: Chills, fever and cold may also occur.
These effects generally disappear once treatment is stopped. If these symptoms persist or worsen, you should consult your health care professional.
Rare side effects
Rare side effects of ondansetron include extrapyramidal reactions, hallucinations and neuroleptic malignant syndrome. These symptoms are particularly worrying if they occur, but are very uncommon.
- Extrapyramidal reactions include tremors or involuntary movements, often of the face or extremities.
- Hallucinations include sensory perceptions in the absence of external stimuli, affecting any of the senses.
- Neuroleptic malignant syndrome is a serious and potentially life-threatening side effect that can cause muscle rigidity, fever and disturbances of consciousness.
Other rare side effects may include heart rhythm disturbances, such as tachycardia or bradycardia, and electrocardiogram (ECG) abnormalities.
Contraindications to ondansetron use
Ondansetron should not be used in patients with a history of hypersensitivity to the drug or any of its components. Patients with signs of subacute intestinal obstruction should be monitored after drug administration, as ondansetron may decrease intestinal activity.
Always consult a health care professional to assess the suitability of treatment.
Precautions when using ondansetron
Ondansetron should be used with caution in patients with heart problems. Similarly, ondansetron should not be taken in combination with apomorphine, used in the treatment of Parkinson's disease, given the interaction between the two molecules.
Special precautions are required in situations favoring torsades de pointes (a dangerous type of tachycardia), liver failure or constipation. Ondansetron may cause adverse effects on the digestive system, notably constipation, which may in rare cases be complicated by ileus or intestinal obstruction, particularly in patients with associated risk factors such as transit slowing agents or a history of digestive surgery.
Alternatives to ondansetron for the treatment of gastroenteritis
Other drugs to relieve the symptoms of gastroenteritis
While ondansetron is an effective way to control the nausea and vomiting associated with gastroenteritis, there are other, more commonly used medications that can also help relieve some symptoms.
- Acetaminophen (marketed under the names Tylenol® and Tempra, among others) can help relieve headaches and fever.
- Dimenhydrinate (marketed under the name Gravol) can be used to relieve heartache.
- Antacids can be used to relieve symptoms of indigestion.
- Certain antibiotics and antiparasitics can be used to treat the underlying causes of gastroenteritis when it is due to a bacterial or parasitic infection.
It is essential to consult a healthcare professional before taking these medications, as they may not be appropriate for everyone and may interact with other medications you are taking.
Before using ondansetron, it is essential to check your eligibility for this medication. Certain health conditions may limit its use. For example, people with an allergy to ondansetron or any of its components should avoid this medication. It is also important to mention any pre-existing heart disease, as ondansetron can affect heart rhythm.
Ondansetron is not recommended for people taking certain medications. Drug interactions can be dangerous and cause serious side effects.
Finally, ondansetron should be used with caution in the elderly, as clinical experience of its use in this population is limited.
Natural remedies for gastroenteritis
There are a number of natural remedies that can be used alongside drug treatment to relieve the symptoms of gastroenteritis.
- Hydration is crucial in the event of gastroenteritis, to compensate for fluid loss due to vomiting and diarrhea. Water, broth or oral rehydration drinks can be consumed regularly.
- A normal, varied diet low in fat and sugar, such as rice, lean meats or cooked vegetables.
These natural solutions, combined with sufficient rest, can help reduce the symptoms of gastroenteritis.
