Etomid

Indications

Etomidate is a fast-acting general anaesthetic given into a vein. It is used to put patients to sleep at the start of general anaesthesia (induction), especially people with heart disease or unstable blood pressure, and sometimes for very short procedures or for emergency insertion of a breathing tube. It is a hospital-only medicine given by an anaesthetist or emergency doctor.

How It Works

Etomidate boosts the action of GABA, the brain's main calming chemical messenger, at GABA-A receptors. This quickly switches off awareness, usually within a minute of injection, and the effect of one dose lasts only a few minutes. Unlike many other anaesthetics it has little effect on heart rate and blood pressure, which is why it is chosen for patients whose circulation is fragile. It does not relieve pain, so pain medicines are given separately.

Dosage and Administration

Etomidate is given only by a doctor trained in anaesthesia, as a slow injection into a vein, with full monitoring and breathing support available. The dose is worked out from the patient's body weight, age and condition, as prescribed. Older people and very sick patients usually need less. It is not used as a long continuous infusion for sedation because it suppresses the adrenal glands.

Interactions

Other medicines that act on the brain add to its effects, including opioid pain medicines such as Fentanyl, sedatives such as Midazolam, other anaesthetics and alcohol, which may deepen sleep and slow breathing. Blood pressure medicines may increase any fall in blood pressure. Tell the anaesthetist about all medicines you take, including steroids, because Etomidate briefly reduces the body's own steroid (cortisol) production.

Contraindications

• Known allergy to Etomidate or any ingredient.
• Adrenal insufficiency (poor adrenal gland function), unless steroid cover is given.
• Long-term sedation in intensive care by continuous infusion.
• Acute porphyria (a rare inherited blood disorder).

Side Effects

Common: pain or burning in the vein during injection, brief involuntary jerking movements of the muscles (myoclonus), nausea and vomiting on waking, hiccups or cough, and a short pause or slowing of breathing. Etomidate temporarily lowers the production of cortisol by the adrenal glands, usually for several hours after a single dose. Rarely, serious allergic reactions occur.

These effects are watched for and treated by the anaesthesia team. After you go home, get urgent medical help if you have difficulty breathing, swelling of the face or throat, a widespread rash, severe or continuing vomiting, fainting, or unusual weakness or confusion.

Pregnancy and Lactation

Etomidate is used in pregnancy, including for Caesarean section, only when the anaesthetist decides it is the best choice; it crosses the placenta. A small amount passes into breast milk; the anaesthetist will advise when breastfeeding can be resumed, which is usually once you are fully awake and recovered.

Precautions and Warnings

• Given only where staff and equipment for airway and breathing support are ready.
• Used with care in severe infection (sepsis) and in people at risk of adrenal problems; steroid cover may be needed.
• Lower doses are used in older people and those with liver cirrhosis or heart failure.
• Do not drive, operate machinery, drink alcohol or sign important documents for at least 24 hours after anaesthesia, and have a responsible adult with you.

Overdose

Overdose is managed by the hospital team. It may cause deep unconsciousness, slowed or stopped breathing and low blood pressure. Treatment is supportive: breathing support, fluids and medicines to raise blood pressure, and Hydrocortisone if adrenal suppression is suspected.

Therapeutic Class

General anaesthetic; intravenous induction agent (non-barbiturate, imidazole derivative).

Storage

Hospital medicine: store as directed on the pack, usually below 25°C, away from light. Do not freeze. Keep out of the reach of children.