IV Induction Agent (Barbiturate) 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 given intravenously for rapid induction of general anaesthesia, including rapid-sequence induction, and for 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: Single induction dose, titrated to effect; no fixed dosage - titrate against age, sex, weight and general condition

Surgical anaesthesia use. Reserved for personnel trained in anaesthesiology, with an anaesthetics-qualified person constantly available. Give a test dose of 25 to 75 mg (1 to 3 ml of 2.5% solution) first and observe for at least 60 seconds. Moderately slow induction in a healthy 60-80 kg adult: 50 to 75 mg at 20-40 second intervals per patient reaction; once anaesthesia established, additional 25 to 50 mg whenever the patient moves. Slow injection minimises respiratory depression and overdose risk; use the smallest dose consistent with the surgical objective. Maintenance (when used as sole agent): small repeated doses as needed or continuous IV infusion at 0.2% or 0.4% concentration, adjusting the rate to control depth. Reduce and carefully titrate the dose in poor general condition, the elderly, hepatic impairment and shock. Keep endotracheal intubation, oxygen and resuscitation equipment ready.

Paediatric dose

Route: Intravenous

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

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. Doses are indicative only for healthy children - individualise and titrate to effect based on age, maturity and general condition; 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 GABA-A receptor activity, enhancing inhibitory chloride currents to produce rapid, dose-dependent central nervous system depression and loss of consciousness.

Prescribing in practice

It is a profound respiratory and cardiovascular depressant that must be given only by those skilled in airway management with full resuscitation equipment immediately to hand, as apnoea and hypotension are expected.
Accidental intra-arterial or extravascular injection causes severe pain, vasospasm and tissue necrosis and is a medical emergency, so confirm secure intravenous access before use.
It is absolutely contraindicated in porphyria and used with great caution in hypovolaemia, severe cardiac disease, fixed cardiac output and reactive airways.

Monitoring

Monitor airway, ventilation, oxygenation, blood pressure and conscious level continuously throughout induction and recovery.

Counselling the patient

You will lose consciousness within seconds of the injection.
Drowsiness and impaired judgement persist afterwards, so do not drive or make important decisions for the rest of the day.

Evidence & guidelines

Thiopental is a long-established induction agent with a well-characterised pharmacological profile reflected in the SPC and UK anaesthetic practice.

Reference: AAGBI; Intraval Sodium SPC; BMA/RPS; 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

Pathways