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This information explains how to use the Jext. Jext is an auto-injector that administers Adrenaline (epinephrine), the emergency treatment for severe allergic reactions. You will have been advised to carry a Jext with you if you are at risk of suffering from anaphylaxis: a severe allergic reaction.

Please remind yourself of these instructions and practice with a trainer pen every few months. Encourage family and /or close friends to practice too.

Administration of the Jext

Step 1

Firmly grip the Jext injector in your hand, holding it round the middle, with your thumb closest to the yellow cap. Do not put your thumb/hand over the end with the black tip.

Step 2

Pull off the yellow cap with your other hand.

Step 3

Place the Jext with the black tip on your outer thigh at a 90 degree angle and push firmly until you hear a ‘click’. Hold the injector firmly in place for at least 10 seconds.

Step 4

Remove the Jext, the black tip will extend automatically and hide the needle. Massage the injection area for 10 seconds. To confirm the adrenaline has been administered, a coloured plastic rod will appear in the inspection window of the Jext.

Step 5

Get urgent medical attention: dial 999. Ask for an ambulance and state “anaphylaxis”

Step 6

If symptoms don’t improve after 5 to 15 minutes, a second dose can be administered.

Jext auto-injector is for single use, it cannot be re-used. Therefore, it is advisable to have two adrenaline injector devices immediately available for use.

It is important to know that the technique of administration of Jext is different to EpiPen. You should not switch between these devices unless you are trained how to use the new one. Jext has identical doses to EpiPen; adult 0.3mg (Jext 300) and child 0.15mg (Jext 150).

Important note

Jext is designed to inject to go directly through the skin or through clothes but will not go through thick clothing (for example denim). Please remove clothing where possible before administering Jext. It will deliver one single dose.

Remember to check the expiry date of Jext every three months, you can register for an expiry date reminder and Jext simulator (trainer device) on the Jext website (opens in a new tab).

Your Jext should be checked regularly to ensure the liquid is clear and colourless. If it appears discoloured or contains particles, the device should be replaced.

Safe disposal of the used Jext

The Jext has a needle protection so no needle is exposed. The ambulance crew or attending doctor will dispose of the used Jext safely.


There are other adrenaline auto injectors (devices) available, e.g. EpiPen® and Emerade®. AnaPen® is available in some other countries but not in UK.

Contact details

For further information please contact:

Allergy Department
Clinic 2a
Box 40

Direct line: 01223 217777

Fax: 01223 216953

Allergy nurses: 01223 348112


The Anaphylaxis Campaign (opens in a new tab)

1 Alexandra Road
GU14 6BU

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Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151