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Jext 300 Solution

  • Adrenaline auto-injector for emergency treatment of anaphylaxis
  • Delivers 300 micrograms adrenaline in a single pre-filled pen
  • Suitable for adults and children over 30kg body weight
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Fast & Free Delivery Options

Variety of delivery options including next day & free delivery.

100% UK-based Pharmacy

Pharmacy, clinic and prescribers based in Greater Manchester.

Free Online Consultations

Start your treatment with a quick and free online consultation.

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About Jext 300 Solution

Jext 300 Solution for Injection is a pre-filled emergency adrenaline auto-injector containing 300 micrograms of adrenaline (epinephrine) in 0.3ml. It is used for the emergency treatment of severe allergic reactions (anaphylaxis) caused by foods, medicines, insect stings or bites, latex, or other allergens.

Jext 300 is designed for rapid administration into the outer thigh and is suitable for adults and children weighing over 30kg (approximately 66 lbs). It delivers a single measured dose of adrenaline to help reverse life-threatening symptoms such as difficulty breathing, swelling of the throat, sudden drop in blood pressure, and severe skin reactions.

It is a Prescription Only Medicine (POM) and should always be carried by individuals at risk of anaphylaxis.

 

Medication Name Jext 300 Solution for Injection
Active Ingredient Adrenaline (Epinephrine) 300 micrograms in 0.3ml
Medication Form Pre-filled adrenaline auto-injector pen
Used to Treat Emergency treatment of anaphylaxis (severe allergic reactions)
Suitable For Adults and children over 30kg body weight
Prescription Required? Yes – Prescription Only Medicine (POM)

What Is Jext 300 Used For?

Jext 300 is used for the emergency treatment of anaphylaxis. Anaphylaxis is a sudden, severe allergic reaction that may include breathing difficulties, swelling of the lips or throat, rash, itching, dizziness, collapse, or loss of consciousness. Immediate injection of adrenaline can be life-saving while waiting for emergency medical assistance.

Who Is Jext 300 Suitable For?

Jext 300 is suitable for:

  • Adults
  • Children weighing more than 30kg

Do not use Jext 300 if:

  • You are allergic to adrenaline or any of the listed ingredients

Speak to your doctor before use if you:

  • Have heart disease or high blood pressure
  • Have diabetes
  • Have overactive thyroid (hyperthyroidism)
  • Have glaucoma
  • Have Parkinson’s disease
  • Are pregnant or breastfeeding

How to Use Jext 300 Auto-Injector

  1. Remove the yellow cap.
  2. Place the black injection tip firmly against the outer thigh (can be given through clothing).
  3. Push hard until you hear a click.
  4. Hold in place for 10 seconds.
  5. Massage the injection area and call 999 immediately.

A second Jext 300 injection may be required after 5–15 minutes if symptoms do not improve. Always seek emergency medical help after using the auto-injector.

Possible Side Effects of Jext 300

Very common or common side effects may include:

  • Rapid heartbeat (palpitations)
  • Shaking or tremor
  • Anxiety or nervousness
  • Headache
  • Dizziness
  • Sweating
  • Nausea or vomiting

Rare but serious side effects may include heart rhythm disturbances or severe increase in blood pressure.

Warnings and Precautions

  • Always carry two auto-injectors if prescribed.
  • Inject into the outer thigh only – never into the buttock, hands, or feet.
  • Check the solution regularly – it should be clear and colourless.
  • Do not use if the solution is discoloured or contains particles.
  • Seek emergency medical attention immediately after use.

Storage Instructions

  • Store below 25°C.
  • Do not refrigerate or freeze.
  • Keep in the original packaging to protect from light.
  • Do not use after the expiry date.

Jext 300 Solution Reviews

Our Experienced UK-based Pharmacy Team

Clinical Consultant
MUDr, MRCEM, EBCEM, FRCEM
GMC no. 7176414

Pharmacist
MPharm
GPhC no. 2065469

Pharmacist
MPharm
GPhC no. 2046514

Page content authored by Amjad Khan, last reviewed by Mr Mohammed on 3rd March 2026.

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