An inhaled anaesthetic gas
Sevoflurane
The most common inhaled anaesthetic, breathed in to send people to sleep and keep them asleep during surgery.
What is Sevoflurane?
Sevoflurane is an inhaled general anaesthetic, breathed in as a vapour to send people to sleep and keep them asleep during surgery. It is given by an anaesthetist, who monitors breathing, heart rate, blood pressure and consciousness. It is the most commonly used inhaled agent in the UK because it is pleasant to breathe and does not irritate the airway, which makes it especially suitable for sending children to sleep by breathing through a mask (gas induction). Like all anaesthetics it can lower blood pressure, and very rarely it can trigger a serious inherited reaction called malignant hyperthermia.
Education and reference only. This is a plain-language guide to Sevoflurane — 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
Sevoflurane is a general anaesthetic given as a vapour that the person breathes in, usually through a mask or a breathing tube, mixed with oxygen. It is given and supervised by anaesthetists, who watch breathing, heart rate, blood pressure and consciousness throughout. It is the most widely used inhaled anaesthetic in the UK, used both to send people to sleep and to keep them asleep during surgery. Because it is gentle to breathe and does not sting the airway, it is the usual choice when anaesthesia is started by breathing the gas, particularly in children.
How it works
Sevoflurane is absorbed through the lungs into the blood and travels to the brain, where it switches off awareness to produce general anaesthesia. The depth of anaesthesia can be adjusted moment to moment by changing how much vapour the person breathes, and it wears off as the gas is breathed back out, allowing fairly quick and smooth waking. Its lack of airway irritation is what makes it comfortable to breathe and well suited to sending children, and some adults, to sleep through a mask.
Company & origin
Originated / developed by: Generic (long-established).
The most widely used inhaled anaesthetic in the UK, breathed in through a mask or breathing tube to send people to sleep and keep them asleep.
Practical use
How to take Sevoflurane
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Sevoflurane is breathed in as a vapour through a mask or breathing tube, given and adjusted by an anaesthetist; it is not something you take yourself.
- Tell the anaesthetic team about your medicines, allergies and any personal or family history of problems with anaesthesia before your operation.
- If you or your child are being sent to sleep with gas, the team will hold the mask gently and talk you through breathing normally.
- You will be monitored throughout, with the depth of anaesthesia adjusted by changing how much you breathe.
- Tell staff if you feel sick or muddled on waking, as this is common, settles, and can be treated.
Weighing it up
Advantages & disadvantages of Sevoflurane
Advantages
- Pleasant and non-irritating to breathe, making it well suited to sending people to sleep through a mask.
- Especially useful for gas induction in children, who may prefer breathing a mask to having a needle first.
- Allows the depth of anaesthesia to be adjusted easily and usually wears off fairly quickly and smoothly.
Disadvantages
- Can lower blood pressure, which the anaesthetic team manages.
- Can cause confusion, restlessness or nausea on waking in some people, especially children.
- Like all anaesthetic vapours, it can very rarely trigger malignant hyperthermia in susceptible people.
Practical use
Good to know
Sevoflurane is given by an anaesthetist who monitors you closely and adjusts the amount you breathe to keep you at the right depth of sleep. Its great advantages are that it is pleasant and non-irritating to breathe, so it can be used to send people to sleep gently through a mask, which is especially helpful for children who may not want a needle first. It can lower blood pressure, which the team manages. As with all anaesthetic vapours, there is a very rare but serious inherited reaction called malignant hyperthermia, in which the body temperature and muscle activity rise dangerously; anaesthetists are trained to recognise and treat it, and will ask about any family history of problems with anaesthesia. Some people feel a little confused or sick on waking, which settles.
Who should not take it / use with caution
- People with a personal or family history of malignant hyperthermia must not be given sevoflurane or other triggering anaesthetics.
- It is used with care in people with certain heart or kidney conditions, with the team adjusting accordingly.
- As with all anaesthetics, the team must know about any previous serious reactions to anaesthesia.
Monitoring
- Continuous monitoring of breathing, oxygen levels, the amount of vapour breathed, heart rate, blood pressure and consciousness.
- Watching closely for any early signs of malignant hyperthermia, such as a rising temperature.
- Reviewing recovery, including any nausea or confusion, after the anaesthetic.
Side effects
- A fall in blood pressure, managed by the anaesthetic team.
- Nausea, confusion or restlessness on waking, particularly in children, which usually settles.
- Very rarely, malignant hyperthermia, a serious inherited reaction that the team is trained to treat.
Key interactions
- Its effects add to those of other anaesthetics, sedatives and strong painkillers; the team balances all of these.
- Care is taken alongside medicines that affect blood pressure or heart rate.
- The anaesthetic team manages its use with muscle relaxants and other agents during surgery.
Available as: Vapour breathed in through a mask or breathing tube, given by an anaesthetist in hospital.
Answers
Sevoflurane: frequently asked questions
Why is sevoflurane used to send children to sleep?
It is pleasant and non-irritating to breathe, so children can be sent to sleep gently through a mask without needing a needle first.
Will I breathe it through a mask or have an injection?
Sevoflurane is breathed in as a vapour through a mask or breathing tube; an anaesthetist adjusts the amount to keep you asleep.
Why might I feel sick or muddled when I wake up?
Nausea and a little confusion are common after inhaled anaesthetics, especially in children; they settle and can be treated.
What is malignant hyperthermia?
It is a very rare, serious inherited reaction to certain anaesthetics in which temperature and muscle activity rise dangerously; anaesthetists are trained to recognise and treat it, which is why they ask about family history.
Will I be aware during my operation?
No. Sevoflurane keeps you asleep, and the anaesthetist monitors you throughout to keep you at the right depth.
Authoritative sources
- BNF
- NICE CKS
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