Having Entonox during a medical procedure

Today you were given Entonox to help with pain and anxiety during a medical procedure.  

Entonox is a mixture of gases called nitrous oxide and oxygen. It is also known as ‘gas and air’.

Entonox wears off very quickly, but you must wait at least 30 minutes after use before driving or using any machinery.  

Like all medicines, Entonox can cause side effects, although not everybody gets them.   

If Entonox is used correctly and just for short-term use, the side effects are small.

Frequency not known:

• dizziness 
• light-headedness 
• tingling 
• disorientation 
• euphoria (feeling very happy) 
• sense of intoxication (feeling drunk)
• feeling sick (nausea) and vomiting (being sick)
• effects on nerve function including feelings of numbness and weakness
• difficulty with breathing
• seizures
• damage to parts of the inner ear
• swollen abdomen (tummy)

If Entonox is used incorrectly for a long period of time, it may:

• change the way your body uses Vitamin B12, which may affect your blood cell count
• decreased your number of white blood cells called granulocytes
• cause addiction 

If you experience any of these side effects, or notice any other unusual effects not mentioned in this information, seek medical advice from your General Practitioner, Pharmacist or 111. In an emergency, please dial 999.

You can also report side effects directly via the Yellow Card Scheme.