Patient info

Medical Nitrous Oxide – patient leaflet, side effects, dosage

Medicine status: Pharmacy medicine (P) Controlled drug (Schedule 5) Details

Medicine strength:
1 ml/ml
Contains active substance:
ATC code:
Similar medicines:

Sources: Original (products.mhra.gov.uk)

Patient leaflet - Medical Nitrous Oxide

Medical Nitrous Oxide

  • Keep this leaflet. You may need to read it again.
  • If you have further questions, please ask your doctor or your pharmacist.
  • This medicine has been prescribed for you personally and you should not pass it on to others. It may harm them, even if their symptoms are the same as yours.

In this leaflet

  • 1. What Medical Nitrous Oxide is and what it is used for.

  • 2. Before you use Medical Nitrous Oxide

  • 3. How to use Medical Nitrous Oxide

  • 4. Possible side effects.

  • 5. Storing Medical Nitrous Oxide

The name of your medicine is Medical Nitrous Oxide. Medical Nitrous Oxide is supplied as a pure gas containing only Nitrous Oxide. It does not contain any other ingredients

1. what is medical nitrous oxide and what it is used for?

Medical Nitrous Oxide is an inhalation gas (a gas that is breathed in). It is colourless and odourless. It is supplied as a pressurised gas in a gas cylinder with a valve to control the outflow of the gas.

It is used as an anaesthetic during surgery and is used to relieve pain when rapid-onset powerful short-term relief of severe pain is needed.

It has anaesthetic effects and can make you relax and send you to sleep. It can also relieve pain by acting on chemical messengers within your body which send messages to the brain when you are injured.

2. before you use medical nitrous oxide

Do not smoke or allow those near you to smoke during treatment with Medical Nitrous Oxide. Nitrous Oxide helps things burn.

Do not allow naked flames near you when you are using Medical Nitrous Oxide

If you suffer from any medical complaint where air is trapped within your body and it might be dangerous for this air to expand or if you are taking strong drugs to make you very sleepy you should not take Medical Nitrous Oxide. Please consult your doctor.

If you have received an injection of gas into your eyes (intraocular injections) within the last 3 months, please consult your doctor.

If you have had epidural anaesthesia you may not be able to use Medical Nitrous Oxide. Please tell your doctor before starting Medical Nitrous Oxide treatment.

Pregnancy

Ask your doctor or pharmacist for advice before taking any medicine.

Medical Nitrous Oxide can be used if you are pregnant.

Breast-feeding

Ask your doctor or pharmacist for advice before taking any medicine.

Medical Nitrous Oxide can be used if you are breast- feeding.

Driving and using machines.

Do not drive or operate heavy machinery whilst taking Medical Nitrous Oxide.

Using other medicines.

Interactions with other medicines are unlikely when Medical Nitrous Oxide in used as directed.

Please inform your doctor or pharmacist if you are taking, or have recently taken any other medicine – even those not prescribed.

3. how to use medical nitrous oxide

Always follow the instructions given to you by your doctor. Do not stop treatment or change your treatment without consulting your doctor first.

You will normally use Medical Nitrous Oxide by breathing the gas in through a mask.

Only use the equipment supplied to you for use with your Medical Nitrous Oxide

All equipment used with the Medical Nitrous Oxide should be kept clean and dry. Do not use oil or grease on any equipment that is used with Medical Nitrous Oxide.

Your doctor or nurse will decide how much Nitrous Oxide you need.

You must always use at least 21% oxygen with nitrous oxide.

If you are at altitude, you should use at least 30% oxygen with nitrous oxide.

If you use Medical Nitrous Oxide for more than 24 hours, or if you use the gas more frequently than every four days, your doctor will take blood tests to check your red and white blood cells.

You must always use the cylinder upright with the valve at the top. Although Medical Nitrous Oxide is gas when it comes out of the cylinder, inside it is liquid. If you use the cylinder on its side this liquid may come out and it may cause burns if in contact with your skin.

Also, you must always open the valve slowly as rapid opening may cause the escaping gas to become liquid again and cause burns if in contact with your skin.

Your doctor will tell you how long your treatment with Medical Nitrous Oxide will last.

If you forgot to use Medical Nitrous Oxide

Take your Medical Nitrous Oxide as soon as you remember, do not take a double dose to make up for the forgotten treatment.

If you use more Medical Nitrous Oxide than you should:

If you may have used more Medical Nitrous Oxide than you should, you will become increasingly light-headed, feel drunk and then become unconscious. If you continue to breathe in too much nitrous oxide you could die.

You must stop taking nitrous oxide and go out in the fresh air.

Mouth-to-mouth resuscitation may be needed and, sometimes, you may be given oxygen.

4. possible side effects

Like all medicines Medical Nitrous Oxide can have side effects.

Some people (about 15%) may feel sick or vomit after receiving Medical Nitrous Oxide.

If you take Medical Nitrous Oxide for a long time you may have ear damage or bowel problems.

If there is extensive use of Medical Nitrous Oxide over a long time, there may be bone marrow changes and also nerve damage but these effects are very rarely seen.

If you notice any side effects not mentioned in this leaflet please inform your doctor or your pharmacist.

5.

The colour of Medical Nitrous Oxide cylinders in the UK is in a period of change.

The colour coding of the shoulder of Medical Nitrous Oxide is blue. The body of the cylinder will be either blue or white.

The aim is to complete a period of change over from the blue body to the white bodied cylinder. The shoulder colour of the cylinder will remain as blue. This period of change will be completed by January 1st 2026

  • Keep Medical Nitrous Oxide out of the reach and sight of children.
  • Do not smoke where Medical Nitrous Oxide is stored.

Medical Nitrous Oxide containers should be stored:

  • in a well ventilated place,
  • under cover
  • kept clean and dry.
  • where they will not be exposed to extremes of temperature.

Use by date

Do not use Medical Nitrous Oxide after the expiry date on the label.

The Marketing Authorisation Holder for Medical Nitrous Oxide is Air Liquide Limited, Station Road, Coleshill, Birmingham, West Midlands, B46 1JY

Medical Nitrous Oxide is manufactured by Air Liquide in the UK.

Date of revision: 10th October 2013

Sources: Original (products.mhra.gov.uk)

Facts about Medical Nitrous Oxide

Prescription needed? No, but it is sold only in pharmacies (P)
Controlled drug
Yes, Schedule 5 of the Misuse of Drugs Regulations?
  • Controlled drugs are medicines that UK law controls more strictly because they can be misused or cause dependence. The Misuse of Drugs Regulations 2001 divide them into 5 schedules: schedule 1 has the strictest rules, schedule 5 the lightest.
  • Schedule 5 has the lightest rules: low-strength preparations, for example of codeine or morphine, with a low risk of misuse.
  • You can buy it in a pharmacy without a prescription.
  • Never give it to anyone else.
Active substance Nitrous oxide
Strength 1 ml/ml
Pharmaceutical form Inhalation gas
How is it taken Inhalation
Excipients None
Is it available? Listed as available (NHS Dictionary of Medicines and Devices – not a record of current supplies)
Shelf life Five years.
Storage Cylinders should be kept out of the reach of children.
Medical Nitrous Oxide is non-flammable but strongly supports combustion (including some materials which do not normally burn in air). It is highly dangerous when in contact with oils, greases, tarry substances and many plastics due to the risk of spontaneous combustion with high pressure gases. Nitrous oxide will decompose at temperatures above 400°C and the speed of decomposition increases with increasing temperature. Explosive decomposition can occur at 650°C at atmospheric pressure.
The normal precautions required in the storage of medical gas cylinders as described below are applicable.
Cylinders should be stored under cover, preferably inside, kept dry and clean and not subjected to extremes of heat or cold.
Cylinders should not be stored near stocks of combustible materials or near sources of heat.
Warning notices prohibiting smoking and naked lights must be posted clearly.
Emergency services should be advised of the location of the cylinder store.
Medical cylinders containing different gases should be segregated and identified within the store.
Full and used cylinders should be stored separately. Full cylinders should be used in strict rotation.
Cylinders must not be repainted, have any markings obscured or labels removed.
F size cylinders and larger should be stored vertically E size cylinders and smaller should be stored horizontally.
Precautions should be taken to protect cylinders from theft.
Drug group (ATC)
  1. N Nervous system drugs
    1. N01 Anesthetics
      1. N01A Anesthetics, general
        1. N01AX Other general anesthetics
          1. N01AX13 nitrous oxide
Marketing authorisation PL 15929/0004 (first authorised 4 February 1998)
Marketing authorisation holder Air Liquide Ltd

Sources: the MHRA product information (products.mhra.gov.uk) and the NHS Dictionary of Medicines and Devices (dm+d), release 10.2.0 of 19 October 2026, NHS Business Services Authority. Contains public sector information licensed under the Open Government Licence v3.0.