Key takeaways:
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A mild sedative, taken shortly before your appointment, may help you cope better during an MRI scan. It relaxes you rather than putting you to sleep.
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Most UK GP surgeries no longer prescribe sedatives for MRI scans, so your referring doctor or your imaging centre will need to arrange a sedative for you.
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Sedation needs to be arranged before the day of your MRI. Imaging centres cannot organise it when you arrive for your appointment.
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After a sedative, you cannot drive for 24 hours, and a responsible adult needs to take you home and stay with you.
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Wide bore scanners, open scanners, feet-first positioning, music and breathing techniques may help you have an MRI without medication.
If you need an MRI (magnetic resonance imaging) scan, and you have claustrophobia or you feel anxious about being in an enclosed space, a sedative may help.
Mild sedatives, prescribed in advance and taken before your appointment, will relax you enough to lie still without sending you to sleep.
This guide explains how MRI sedation works, who can prescribe it, what happens on the day and the alternatives that help you manage without medication at all.
What Sedation Options Are Available?
There are three different types of sedation for an MRI.
Anxiety Medication
Anxiety medications, or anxiolytics, are prescription drugs that reduce anxiety. For MRI scans, this usually means a single low-dose benzodiazepine tablet, such as diazepam, also known as Valium.
When you take these drugs, you’re able to stay awake and follow instructions during your MRI scan, but you’ll feel calm and less anxious and panicked.
Oral anti-anxiety medications are used to support patients having an MRI in an outpatient department or scanning centre, under the supervision of a medical team. They’re the mildest and most common form of sedation for an MRI.
Conscious Sedation Given Intravenously
If you’ve tried to have an MRI with a low-dose anxiolytic and been unsuccessful, your medical team may consider stronger sedation, injected into a vein in your arm. It will make you feel very drowsy, and you may not remember much of your scan.
You’ll be able to breathe on your own, but because your breathing and heart rate will need to be monitored throughout, this level of sedation is only available in hospital settings with a trained sedation team present.
General Anaesthetic
Adults rarely require a general anaesthetic to undergo an MRI. They’re reserved for severe cases of anxiety when all other attempts at an MRI have failed, but it’s medically necessary to have one. A general anaesthetic is more common for babies and young children needing an MRI, who cannot keep still while awake.
During a general anaesthetic, you’re asleep and fully unconscious, with an anaesthetist managing your breathing and monitoring your heart rate until you’re awake. You won’t recall anything about your scan.
MRI Scanners and Claustrophobia
Claustrophobia is a fear of confined spaces, and the inside tunnel of an MRI scanner, called the bore, is a confined space. Therefore, if you have claustrophobia, it’s understandable that you’ll feel anxious about having an MRI. But knowing what to expect may help.
What Does it Feel Like Being Inside an MRI Machine?
The bore of a standard MRI machine is around 60cm in diameter. This means that during an MRI scan, you’ll move inside a tunnel measuring 60cm across. Wide bore MRI scanners have a larger tunnel diameter of 70cm and may help ease feelings of claustrophobia. Either way, an MRI machine is open and lit at both ends. Open MRI scanners have open sides, which may help you feel more relaxed.
For an MRI scan, you’ll be dressed in a medical gown and positioned on a table, lying down, usually on your back. You’ll be asked to remain still during the scan, and there may be times when you’re asked to hold your breath for a moment.
The table slowly moves into the scanner. Depending on the body part being scanned, your head may sit inside the bore, near its opening, or outside it entirely. You may enter the machine headfirst or feetfirst.
MRI machines make loud knocking sounds while they work, so you'll be given earplugs or headphones to help reduce the noise. You’ll be able to speak to your medical team via an intercom, and you’ll be given a call button to hold in one hand, which you can press at any time to stop the scan.
The scan will take between 30 and 90 minutes, depending on the area being scanned and the type of MRI scan.
How Often Claustrophobia Stops a Scan
Around 1 in 10 people in the UK experience claustrophobia. Research suggests roughly two million scans a year worldwide are abandoned or refused because of it.
Who is Suitable for Sedation?
A low-dose sedative is suitable if you have:
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Claustrophobia that you think will be triggered by having an MRI
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A history of panic attacks in confined spaces
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Previously tried unsuccessfully to have an MRI without sedation
Sedatives can occasionally make people feel more restless and distressed, and they interact with alcohol, increasing their sedative effect. They also interact with some medications, such as some antidepressants and sleeping tablets, and aren’t suitable if you have certain medical conditions, such as sleep apnoea or advanced COPD.
Following a sedation, you won’t be able to drive, operate machinery or care for vulnerable or young people alone for 24 hours.
Your medical team will take all of this into account when deciding whether to prescribe a mild sedative. This is why it’s not possible to arrive at your MRI appointment and receive sedation without organising it beforehand.
Sedation Prescriptions and Your GP
In the UK, it’s standard practice for GPs to refuse to prescribe a sedative for an MRI scan. Your GP has no way to monitor you in the scanner, or to time a dose around an appointment that might run late.
What the Royal College of Radiologists Guidance Says
In 2024, the Royal College of Radiologists published the third edition of its guidance, Sedation, analgesia and anaesthesia in radiology. It states that a trained and credentialed team should administer sedation, that patients requiring sedation should have a pre-procedure assessment and a sedation plan and that sedated patients should be appropriately monitored.
Therefore, responsibility sits with the imaging centre, not with a GP who isn’t present during a scan.
Who Can Prescribe and Supervise Instead
If you think you’ll need a mild sedative to help you through an MRI scan, speak to your referring doctor or Scan.com clinician if you are self-referring. These medical professionals know why the scan is needed, whether a different scan would answer the same question and what their imaging department can safely supervise.
How to Book a Sedated MRI
Ask to be considered for sedation when you book, not on the day. At Scan.com, each booking is reviewed by a member of our medical team, who will call you to ask you some questions about your scan.
Ask about the possibility of sedation and, if suitable, when to take the medication so that it works at the right time for your scan. Let them know about any medications and medical conditions, as well as any past adverse reactions to sedatives.
If sedation isn’t possible, ask whether a wide bore or open MRI scanner is available.
What Happens on the Day of a Sedated MRI
A sedated appointment runs much like a standard one, with three extra considerations.
Timing the Tablet Correctly For Your Appointment Slot
Your medical team will tell you when to take the tablet, typically a set time before your scan is due to start, so it works optimally at your appointment. Some clinics prefer you to bring the medication with you and take it there so that you can be monitored.
Monitoring While You’re in the Scanner
You'll be asked the standard MRI safety questions, covering metal implants, pacemakers and previous surgery, and your team will note that you've taken a sedative.
Your radiographer will monitor you throughout the scan and talk to you through a two-way intercom. The call button will stay in your hand from start to finish.
Recovery, Driving and Getting Home
You cannot drive for 24 hours after taking a sedative, so arrange for an adult to collect you and stay with you for 24 hours. Avoid alcohol for the rest of the day, and expect to feel drowsy or a little unsteady for several hours. Most people are back to normal by the next morning.
Side Effects and Risks
For a single low-dose sedative, taken under medical direction, side effects are usually mild. They may include drowsiness, light-headedness, slowed reactions and patchy memory of the appointment. Serious complications, such as breathing difficulties, are rare but are the reason you’re monitored closely.
Never take someone else's medication, a leftover tablet from an old prescription, medication prescribed for a different procedure or medication your imaging team doesn't know about. If your imaging team are unaware that you’ve taken a sedative, they won’t necessarily be able to reach you quickly enough if you have an adverse reaction.
Sedation Compared With a General Anaesthetic
Mild oral sedatives leave you awake, able to hold your breath on request and free to go home shortly after the scan, with an adult to supervise you for 24 hours.
A general anaesthetic involves fasting beforehand, an anaesthetist and full monitoring during the scan, a recovery period afterwards and a hospital setting rather than an outpatient clinic. For adults, it's a last resort and for babies and young children, who cannot keep still while awake, it's sometimes the planned first choice.
Alternatives Worth Trying First
There are alternatives to sedative medications to help anxious and claustrophobic patients through an MRI scan.
Wide Bore and Open Scanners
A wide bore scanner provides roughly 10cm more space around your body than a standard machine. An open MRI scanner is open at the sides, so the room and space are visible around you.
Open MRI machines generally use a lower magnetic field, so image quality can be lower for certain examinations, and your imaging team will advise whether one suits the scan you need. Our guide to open and upright MRI scans covers the differences in detail.
Feet First rather than Head First
For scans of the knee, ankle, hip and lower spine, many machines can scan you feet first, so your head stays at the opening of the tunnel or outside it altogether.
Covering Your Eyes
You may find that an eye mask and keeping your eyes closed from the moment you lie down is enough. Alternatively, prism glasses contain angled lenses that bend your line of sight, so while lying flat, you’ll see along the tunnel to the room beyond, rather than the roof of the bore.
Musical Distractions
Ear protection is compulsory due to the scanner noise, and at many clinics, headphones can play the music of your choice during suitable scans.
Focusing on familiar music may help fade the machine's noise into the background. The call button in your hand means you’re in control and you can stop the scan if you need to.
Bringing Someone Into the Scan Room
Some clinics may allow a friend or relative into the scanning room with you once they've completed the safety screening. You may feel more relaxed knowing that someone you trust is nearby.
Using Breathing and Grounding Techniques
Slow, structured breathing can settle a racing heart and shallow breaths. Practice box breathing before your scan, and try using it in the scanner. Breathe in for a count of four, hold for four, breathe out for four, hold for four and repeat.
Counting the scanner's knocks, reciting text or a poem, naming objects you can feel or mentally walking a familiar route all work in a similar way.
Visiting the Scanner Before Your Appointment
Sometimes the unknown is the biggest fear, and it may be possible to visit the imaging centre a few days before your appointment to familiarise yourself with the surroundings.
You may find it helpful to stand in the scanning room and see and hear how the machine works. Ask your centre if this is possible. Some clinics will also slide you in and out of the scanner a couple of times so you can feel how quickly you can be brought out.
Sedation for Children Having an MRI
Babies and young children may be given a general anaesthetic for an MRI because the scan only works when you keep still. Older children may manage with practice sessions using a toy scanner, having a parent in the room and feet-first positioning where possible. Your medical team will advise the best course of action.
More Information
FAQs
Can I take my own diazepam before an MRI?
No, only ever take a sedative prescribed for a specific scan on a specific occasion, with the clinic's knowledge. Your clinic may decline to scan you if you arrive sedated without warning.
Will a sedative send me to sleep?
A mild oral sedative will not make you fall asleep, you’ll be able to breathe unaided, follow the radiographer's instructions and use the call button if necessary. Stronger intravenous sedation makes you drowsy, but it is only given in hospital settings with a monitoring team present.
Can I drive home after a sedated MRI?
No, you shouldn’t drive for 24 hours after taking a sedative for a scan, so arrange for someone to collect you and stay with you overnight. Sedatives slow your reactions long after you stop feeling drowsy, which is why the restriction lasts a full day rather than a few hours.
Does sedation affect the quality of the images?
A mild sedative has no negative effect on the scan images. It may actually help make them clearer and sharper if you’re sedated and able to remain still.
Do I need to fast before a sedated MRI?
Not usually for a mild oral sedative, but follow your prescriber's instructions, as advice varies with the medicine and your health. Some scans require you to avoid food and drink for a few hours beforehand, regardless of sedation, particularly abdominal scans and some scans with contrast dye. A general anaesthetic always requires fasting, which the hospital will explain when the scan is arranged.
What happens if the sedative doesn’t work?
You can stop the scan at any time by pressing the call button. The next step might be a second attempt with stronger, monitored sedation in a hospital setting, a wide bore or open scanner or a different scan altogether.
Can I have an MRI under general anaesthetic instead?
For adults, a general anaesthetic for MRI is uncommon and reserved for situations where the scan is essential, and all other approaches have failed.
How far in advance do I need to arrange sedation?
Raise it when you book the scan, not in the days leading up to it. Your team will need time to assess you, issue a prescription, inform you when you should take it and possibly rearrange your appointment to accommodate your sedation.
References
Royal College of Radiologists. (2024). Sedation, analgesia and anaesthesia in radiology, third edition. rcr.ac.uk. https://www.rcr.ac.uk/our-services/all-our-publications/clinical-radiology-publications/sedation-analgesia-and-anaesthesia-in-radiology-third-edition/
NHS inform. (2026, May 6). MRI scan. nhsinform.scot. https://www.nhsinform.scot/tests-and-treatments/scans-and-x-rays/mri-scan/
Website, N. Claustrophobia. nhs.uk. https://www.nhs.uk/conditions/claustrophobia/
University Hospitals Plymouth NHS Trust. Aftercare for people with claustrophobia (patient information leaflet). plymouthhospitals.nhs.uk. https://www.plymouthhospitals.nhs.uk/display-pil/pil-aftercare-for-people-with-claustrophobia-4166/
Hudson, D.M., Heales, C., & Meertens, R. (2023). Supporting claustrophobic patients during Magnetic Resonance Imaging examination: the patient perspective. Radiography. https://www.radiographyonline.com/article/S1078-8174(23)00175-X/fulltext
