A medicine used to prevent and treat nausea and vomiting
Dolasetron
An anti-sickness medicine used to prevent and treat nausea and vomiting, working by blocking a chemical that triggers sickness.
What is Dolasetron?
Dolasetron is an anti-sickness medicine from the group known as 5HT3 antagonists, used to prevent and treat nausea and vomiting linked to chemotherapy or surgery. It works by blocking the action of serotonin on the part of the body that triggers sickness. The most important safety issue is that it can affect the heart's electrical rhythm by prolonging what is called the QT interval, and for this reason the injectable form is restricted because of the risk to heart rhythm. It can also cause constipation and headache. It is used under medical supervision.
Education and reference only. This is a plain-language guide to Dolasetron — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Dolasetron is an anti-sickness medicine that belongs to a group called 5HT3 antagonists, which are widely used to stop the nausea and vomiting that can come with cancer treatment or surgery. It works on the messaging system that sets off the vomiting reflex, calming the signals that make a person feel sick. It comes as a tablet and as an injection, although the injectable form is restricted because of its effect on heart rhythm. It is prescribed and supervised by healthcare professionals, often as part of a planned anti-sickness regimen.
How it works
When the body is exposed to triggers such as chemotherapy, it releases serotonin, a chemical that acts on receptors in the gut and brain to set off feelings of sickness and the vomiting reflex. Dolasetron blocks these particular serotonin receptors, known as 5HT3 receptors, so the sickness signal is dampened down. By heading off this trigger, it helps prevent vomiting and reduces nausea. It is most effective when given before or around the time of a known sickness trigger, such as a chemotherapy session, rather than waiting for vomiting to set in.
Company & origin
Originated / developed by: Specialist manufacturers.
A medicine used in the UK to prevent and treat nausea and vomiting, particularly with chemotherapy or after surgery.
Practical use
How to take Dolasetron
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it as prescribed, usually before or around the time of a known sickness trigger such as chemotherapy, rather than waiting for vomiting to start.
- Swallow tablets whole with water; the injection is given by a healthcare professional.
- Tell your team about any heart-rhythm problems or a family history of them before it is given.
- Mention all your other medicines, as some can add to the effect on the heart's rhythm.
- Let your team know if you become constipated, as this is a common effect that can usually be managed.
Weighing it up
Advantages & disadvantages of Dolasetron
Advantages
- Effective at preventing and treating nausea and vomiting linked to chemotherapy or surgery.
- Available as a tablet, making it convenient when sickness is expected.
- Works on a specific trigger of sickness, so it can be planned around treatments.
Disadvantages
- Can affect the heart's electrical rhythm by prolonging the QT interval, and the injectable form is restricted because of this.
- Commonly causes constipation because it can slow the gut.
- Can cause headache, and is used with care in people with heart-rhythm problems.
Practical use
Good to know
The most important thing to know about dolasetron is its effect on the heart's electrical rhythm: it can prolong what is called the QT interval, which in some people can lead to dangerous heart-rhythm changes. Because this risk is greater with the injection, the injectable form is restricted, and the medicine is used with care in anyone with heart-rhythm problems or low levels of body salts such as potassium or magnesium. A common and more everyday side effect is constipation, because these medicines can slow the gut, along with headache. It works best when used to prevent sickness rather than to rescue someone who is already vomiting, so it is usually given ahead of a known trigger. Tell your team about any heart problems and all the other medicines you take, as some can add to the heart-rhythm risk.
Who should not take it / use with caution
- People who have had a serious allergic reaction to dolasetron or similar anti-sickness medicines should not take it.
- It is used with great caution, or avoided, in people with certain heart-rhythm problems such as a prolonged QT interval.
- It is used with care in people with low levels of body salts such as potassium or magnesium, which can add to the heart-rhythm risk.
Monitoring
- Checking heart rhythm and the QT interval where there is any concern, especially before the injection.
- Checking levels of body salts such as potassium and magnesium when needed.
- Reviewing how well sickness is controlled and watching for constipation.
Side effects
- Constipation, as the medicine can slow the gut.
- Headache and dizziness in some people.
- Less commonly, changes in the heart's electrical rhythm (a prolonged QT interval), which is why heart problems are checked.
Key interactions
- Other medicines that affect the heart's QT interval can add to the risk, so a full medicines list is important.
- Low levels of potassium or magnesium, sometimes caused by other medicines, increase the heart-rhythm risk and may need correcting first.
- Tell your team about all your medicines, including ones bought without a prescription.
Available as: Tablets and a solution for injection, with the injection restricted because of heart-rhythm risk.
Answers
Dolasetron: frequently asked questions
What is dolasetron used for?
It is an anti-sickness medicine used to prevent and treat nausea and vomiting, particularly the kind linked to chemotherapy or surgery.
Why is the injection restricted?
The injectable form can affect the heart's electrical rhythm by prolonging the QT interval, so it is restricted because of the risk to heart rhythm.
Does it cause constipation?
Yes, constipation is a common side effect because the medicine can slow the gut; tell your team if it troubles you so it can be managed.
When should it be taken?
It works best when used to prevent sickness, so it is usually given before or around the time of a known trigger such as a chemotherapy session.
Why does my heart need checking?
Because it can prolong the QT interval, your team may check your heart rhythm and your body-salt levels, especially if you have heart problems.
The wider class
About Anti-sickness medicine (5HT3 antagonist)
Dolasetron belongs to the anti-sickness medicine (5ht3 antagonist) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
Browse by body system
Authoritative sources
- BNF
- NICE CKS
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