JEXT

What it is

Jext is available in two strengths: Jext Jnr 150, which delivers 150 micrograms of adrenaline (epinephrine) as acid tartrate, and Jext 300, which delivers 300 micrograms of adrenaline (epinephrine) as acid tartrate. The medicine is supplied as a solution for injection in a pre-filled cartridge based auto-injector. Jext contains sulfites.

Approved indications

— Emergency treatment of anaphylaxis (acute severe allergic reactions) due to insect stings or bites, foods, drugs or other allergens.

Dosing overview

An initial dose should be administered as soon as symptoms of anaphylaxis are recognised. In the absence of clinical improvement or if deterioration occurs, a second injection with an additional Jext may be administered 5–15 minutes after the first injection. It is recommended that patients are prescribed two Jext pens which they should carry at all times. Jext is for intramuscular administration into the anterolateral thigh. Patients should be advised not to inject Jext into the gluteus maximus due to the risk of accidental injection into a vein.

Key safety warnings

Do not inject intravenously as cerebral haemorrhage may occur due to a sharp rise in blood pressure. Special caution should be taken in patients with cardiovascular diseases including angina pectoris, obstructive cardiomyopathy, cardiac arrhythmia, cor pulmonale, atherosclerosis and hypertension, and with caution in patients with ventricular fibrillation, cerebral arteriosclerosis, prefibrillatory rhythm, tachycardia, myocardial infarction, phenothiazine-induced circulatory collapse and prostatic hypertrophy. Adrenaline can cause potentially fatal ventricular arrhythmias including fibrillation, especially in patients with organic heart disease or those receiving other drugs that sensitise the heart to arrhythmias. Jext contains sodium metabisulfite which may rarely cause severe hypersensitivity reactions including anaphylactic symptoms and bronchospasm in susceptible people, especially those with a history of asthma. Rare cases of serious skin and soft tissue infections, including necrotising fasciitis and myonecrosis caused by Clostridia (gas gangrene), have been reported at the injection site following adrenaline injection for anaphylaxis; do not inject Jext into the buttock and advise patients to seek medical care if they develop signs or symptoms of infection, such as persistent redness, warmth, swelling, or tenderness, at the adrenaline injection site. Patients and carers should be informed about the possibility of biphasic anaphylaxis which is characterised by initial resolution followed by recurrence of symptoms some hours later.

Contraindications

There are no absolute contraindications to the use of Jext during an allergic emergency.

Regulatory history

Jext 300 (adrenaline (epinephrine) as acid tartrate 300 microgram/0.3 mL solution for injection pre-filled cartridge auto-injector) and Jext Jnr 150 (adrenaline (epinephrine) as acid tartrate 150 microgram/0.15 mL solution for injection pre-filled cartridge auto-injector) were first listed on the ARTG on 14 November 2025.