Barbiturate Induction Agent Pregnancy: Can be used without adverse effects during pregnancy, but only when expected benefits outweigh potential risks (animal studies showed reproductive toxicity). Crosses the placenta and appears in breast milk - suspend breast-feeding for at least 12 hours (or express milk) before induction.

Thiopental Sodium

Brand names: Intraval Sodium

Thiopental sodium is an ultra-short-acting barbiturate used for the induction of general anaesthesia and for the control of refractory status epilepticus and raised intracranial pressure.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Induction of anaesthesia: 4 to 6 mg/kg body weight

Route: Intravenous only (infusion only through a central venous catheter)

Frequency: Titrated to effect; no fixed dosage - titrate against patient age, sex, weight and general condition

Reserved for personnel trained in anaesthesiology. Give a test dose of 25 to 75 mg (1 to 3 ml of 2.5% solution) first, then observe for at least 60 seconds. Slow induction in a healthy 60-80 kg adult: 50 to 75 mg at 20-40 second intervals per patient reaction, with additional 25 to 50 mg whenever the patient moves. Maintenance by small repeated doses or continuous IV infusion (0.2% or 0.4% concentration). Convulsive states: 75 mg to 125 mg (3-5 ml of 2.5% solution) as soon as possible after the convulsion begins. Raised intracranial pressure (with controlled ventilation): intermittent bolus 1.5 to 3 mg/kg. Reduce dose in the elderly, poor general condition, hepatic impairment, shock, and other listed conditions.

Paediatric dose

Route: Intravenous

Frequency: Induction: single dose then further doses as needed; titrate to effect

Max: Convulsive states: do not exceed 5 mg/kg/h

Induction of anaesthesia per SPC (age-banded ranges, no single per-kg value): Newborns IV 3 to 4 mg/kg then 1 mg/kg as needed; Infants IV 5 to 8 mg/kg then 1 mg/kg as needed; Children IV 5 to 6 mg/kg then 1 mg/kg as needed. Convulsive states: 2 mg/kg IV initially then individually titrated (maximum 5 mg/kg/h). Safety in paediatric raised intracranial pressure not established. Individualise and titrate to effect; verify against a children's formulary.

Dose adjustments

Renal

Use with caution in severe renal disease; reduced doses are indicated (also in the elderly and after narcotic analgesic premedication).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to barbiturates or to any excipient
Respiratory obstruction
Acute asthma
Severe shock
Dystrophia myotonica
Porphyria (any barbiturate is contraindicated)

Side effects

Cardiac: myocardial depression, hypotension, heart arrhythmia (common)
Respiratory depression, bronchospasm, laryngospasm, coughing, sneezing (common)
Somnolence and delayed wakening (common)
Nausea and vomiting (common); shivering, thrombosis, phlebitis, pain at administration site
Anaphylactoid reactions - urticaria, bronchospasm, fall in blood pressure, angioedema

Interactions

Patients on long-term aspirin, oral anticoagulants, oestrogens, MAOIs or lithium may need to adjust the dose or stop therapy prior to elective surgery (SPC section 4.4)
Patients with diabetes or hypertension may need to adjust their therapy before anaesthesia

Clinical monograph

How it works

It potentiates the inhibitory action of GABA at the GABA-A receptor, prolonging chloride channel opening and producing rapid central nervous system depression.

Prescribing in practice

Causes dose-dependent cardiorespiratory depression and hypotension; have airway support and resuscitation facilities immediately available.
Inadvertent intra-arterial injection causes intense vasospasm and tissue ischaemia, while extravasation is highly irritant due to the strongly alkaline solution.
Contraindicated in acute porphyria, as barbiturates can precipitate an acute attack.

Monitoring

Continuous monitoring of airway, oxygenation, blood pressure and depth of anaesthesia is required throughout administration and recovery.

Counselling the patient

This is given in a closely monitored anaesthetic or critical care setting.
Drowsiness and impaired coordination persist after the procedure, so do not drive or operate machinery until fully recovered.

Evidence & guidelines

Thiopental is a long-established induction agent and its use is supported by anaesthetic practice standards and the SPC.

Reference: Stoelting's Pharmacology and Physiology in Anaesthetic Practice; RCoA Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators