Entonox

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What is this information about?

This information is about a drug called Entonox. It is a gas that relieves pain. This information tells you about using Entonox if you have certain medical conditions; how to use Entonox; and any side effects you might have.

Why have I been given this information?

You have been given this information because you may be offered Entonox when you have your orthopaedic procedure.  

It is important to read this information carefully so you can tell staff if you have a medical condition that means you cannot have Entonox. It is also important to be aware of possible side effects, and what to do if you experience them.

What is Entonox?

Entonox is a gas used to relieve pain during some orthopaedic procedures. It is a mixture of half nitrous oxide and half oxygen.  

The gas is breathed in through a mask. It is fast-acting and gives pain relief quickly. It wears off within one minute when you stop breathing it in.

Can I use Entonox if I am pregnant?

No. Entonox should not be used in the first or second trimester of pregnancy. Please tell us if you are in the first or second trimester of pregnancy.

Is Entonox unsafe to take if you have certain medical conditions?

Yes. If you wish to use Entonox during your procedure you must tell us about any medical conditions you have. 

Entonox can cause a rise in intra-cranial pressure (pressure inside your skull) so should not be used if you have had recent:

• head injuries 
• injuries to the face and jaw 
• suspected or known increased pressure on the brain 
• eye surgery, involving gas bubble insertion

Other examples where air may be trapped in the body and where Entonox should never be used are:

• pneumothorax 
• abdominal distension 
• suspected intestinal obstruction 
• bullous emphysema 
• middle ear procedures 
• for 48 hours after a dive.

Please tell us if any of these apply to you.

Do I need to tell staff if I am taking any other medication?

Yes. Please tell staff if you are taking methotrexate. Taking Entonox may influence your blood cell count.

How do I use Entonox?

Entonox is self-administered. This means that you must be able to hold the mouthpiece and inhale the gas.  

We will make sure you are able to use the Entonox equipment. The supply will be set up and ready for you.  

The mouthpiece we give you has a demand valve. The demand valve makes sure that gas is released for you only when you suck on the mouthpiece. 

It may take up to two to three minutes of inhalation before the gas takes effect. The effect will quickly wear off when you are not breathing in the gas.  It is more effective if you keep a regular rhythm when breathing in and out.   

It is common to have a dry mouth and throat when using Entonox. If you have earache when using the gas, then please stop using it and tell staff.

Can I drive and use machinery after using Entonox?

You must wait at least 30 minutes after using Entonox before driving or using machinery. A benefit of Entonox is you do not need anyone to escort you home and can function as normal afterwards.

Are there any side effects?

Common side effects include:

• dizziness 
• light-headedness 
• nausea (feeling sick) 
• tingling 
• disorientation (feeling confused)

Other side effects include:

• ear problems because of increased pressure inside the ear 
• tiredness  
• bowel enlargement because of trapped wind

Rare side effects include:

• effects on nerve function (numbness and weakening) 
• breathing difficulties 
• addiction

Who can I contact for further information and advice?

Please contact the Plaster Room on 01273 696955 extension: 64241, 8.30am to 5.30pm, Monday to Thursday and 8.30am to 12.00pm Friday. Outside of these times, please contact 111 for advice.