Thiopen

Indications

Thiopentone Sodium (also called Thiopental) is a fast-acting anaesthetic given into a vein to start general anaesthesia before surgery. It may also be used for short procedures, to control severe seizures that do not respond to other treatment, and occasionally to reduce raised pressure inside the skull in intensive care.

How It Works

Thiopentone is a barbiturate. It boosts the action of GABA, the brain's main calming chemical, which quickly depresses brain activity. Unconsciousness begins within about 30 to 60 seconds and, after a single dose, lasts only a few minutes as the drug spreads from the brain into other body tissues.

Dosage and Administration

Thiopentone is given only by an anaesthetist or trained doctor in a hospital setting with full resuscitation equipment. The powder is dissolved before use and injected slowly into a vein. The dose depends on body weight, age, general health and response, and is given as prescribed.

Interactions

Opioid painkillers, benzodiazepines, alcohol, other anaesthetics and blood pressure medicines increase its effects on breathing and blood pressure. Sulfonamide antibiotics may increase its effect. It is incompatible with many medicines when mixed in the same syringe, such as some muscle relaxants. Tell the anaesthetist about all medicines you take.

Contraindications

It must not be used in people with porphyria, a known allergy to barbiturates, blocked airways or when the airway cannot be secured, or severe uncontrolled asthma. It is used with great caution in shock, severe heart disease or very low blood pressure.

Side Effects

Possible effects include drop in blood pressure, slowed or stopped breathing (which the anaesthetist manages), cough, hiccups, spasm of the voice box or airways, pain at the injection site and drowsiness or confusion on waking. Injection outside the vein or into an artery can cause severe tissue damage.

Tell staff at once, or get urgent medical help after discharge, if you have severe pain, colour change or swelling at the injection site, breathing difficulty, rash or swelling of the face, or unusual drowsiness that does not improve.

Pregnancy and Lactation

It can be used in pregnancy, including for caesarean section, when the anaesthetist decides it is appropriate; it crosses the placenta and the newborn is monitored. Small amounts pass into breast milk; breastfeeding can usually continue once the mother is awake and alert, as advised by the doctor.

Precautions and Warnings

Do not drive, operate machinery, drink alcohol or make important decisions for at least 24 hours after anaesthesia, and have an adult with you. Doses are reduced in older people, and in heart, liver or kidney disease. Repeated doses build up in the body and can cause prolonged sleep.

Overdose

Overdose causes deep unconsciousness, stopped breathing and very low blood pressure. It is managed by the anaesthetist with breathing support and treatment of blood pressure.

Therapeutic Class

General anaesthetic, ultra-short-acting barbiturate.

Storage

Hospital item: store the powder below 25°C, away from light, as directed on the pack. Once mixed, use promptly and discard any unused solution or solution that is cloudy.