Thiopental

What thiopental sodium is and how it works

Thiopental is an ultrashort-acting barbiturate general anaesthetic agent used for induction of anaesthesia and management of refractory convulsions or elevated intracranial pressure. It is administered exclusively by anaesthetists in a hospital or operating theatre setting. (2) (5) (1)

Thiopental is not available in the United States (discontinued in 2011) or Canada (currently unavailable), but remains authorised and marketed in the United Kingdom and Australia. It is never self-administered; you will only receive it in a hospital under direct medical supervision.

Mechanism of action: how thiopental sodium works

Thiopental sodium is a thiobarbiturate that binds to the GABA-A receptor, enhancing the effect of the inhibitory neurotransmitter GABA. This produces rapid loss of consciousness with a single intravenous dose. (2)

What thiopental sodium is used for

Before taking thiopental sodium

Do not take / not appropriate for

• Do not receive thiopental if you have porphyria (a group of rare blood disorders) — barbiturates are absolutely contraindicated. (all products) (2)
• Do not receive thiopental if you have a known hypersensitivity to barbiturates or any ingredient of the product. (all products) (2)
• Thiopental is not used if you have respiratory obstruction, acute asthma, severe shock, or the muscle disorder dystrophia myotonica. (all products) (2)

Tell your clinician about

• Any history of porphyria or suspected porphyria.
• Any allergy to barbiturates or other anaesthetic drugs.
• All your current medical conditions (asthma, breathing problems, heart or blood pressure problems, liver disease, muscle disorder).
• If you are pregnant, planning to become pregnant, or breastfeeding.
• All medicines you are taking, including other anaesthetics, sedatives, or alcohol.

How to take thiopental sodium

• Thiopental is injected into a vein by an anaesthetist in a hospital or clinic setting. You will be continuously monitored.
• The dose is determined by your body weight, medical condition, and response.
• A small test dose may be given first to check your tolerance.
• Thiopental is never for self-administration or use outside a controlled medical environment.

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (2) (5) (1) (3) (4) (6)

Missed dose

Thiopental is administered as a single dose or continuous infusion during a medical procedure; there is no missed dose scenario outside the hospital setting.

Overdose

Overdose can cause severe respiratory depression, cardiovascular collapse, and coma. Management is supportive, with mechanical ventilation and cardiovascular support. This would be managed immediately by the anaesthesia team. (2)

Side effects

All side effects are monitored and managed by the anaesthesia team during administration. The following effects have been reported:

Serious warnings

Interactions

Pregnancy, breastfeeding, kidney/liver function, age

Monitoring

Before starting

• Assess for contraindications: porphyria history, barbiturate allergy, respiratory obstruction, severe shock, dystrophia myotonica.
• Confirm airway and cardiovascular status.
• Check hepatic function if clinically indicated.
• Ensure resuscitation equipment is available.

During treatment

• Continuous monitoring of heart rate, blood pressure, oxygen saturation, and respiratory rate.
• Inspect injection site for signs of extravasation or intra-arterial placement.
• Watch for laryngospasm, coughing, or sneezing at induction.
• Monitor depth of anaesthesia and adjust dose accordingly.

Storage

Thiopental powder for injection should be stored according to the manufacturer’s instructions. Typically, it is stored below 25°C, protected from light. The reconstituted solution must be used promptly; any unused solution should be discarded as per local protocol. Consult the specific SmPC for exact storage requirements.

Frequently asked questions

References

1. Thiopental sodium (Pentothal) discontinued in the United States in 2011Multiple sources (ASA statement, news reports, secondary databases) · United States · dated 2011 · accessed 2026-07-30 · source 1
2. Thiopental 500mg Powder for Solution for Injection - Summary of Product Characteristicselectronic Medicines Compendium (UK) · United Kingdom · dated 2023-11-10 · accessed 2026-07-30 · source 2
3. No centralised marketing authorisation for thiopental; nationally authorised in some member statesEuropean Medicines Agency · European Union · accessed 2026-07-30 · source 3
4. Drug Product Database - Thiopental sodiumHealth Canada · Canada · accessed 2026-07-30 · source 4
5. OMEGAPHARM THIOPENTAL SODIUM 470 mg and PENTOTHAL 500 mg powder for injection vials - ARTG registrationsTherapeutic Goods Administration · Australia · accessed 2026-07-30 · source 5
6. No current dedicated data sheet for thiopental foundMedsafe (New Zealand Medicines and Medical Devices Safety Authority) · New Zealand · accessed 2026-07-30 · source 6

Brand names by country

Single-ingredient thiopental sodium names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries