Pharmacology · Intravenous anaesthetics
Propofol !
Intravenous anaesthetic with fast onset and fast wake-up, the most used to induce anaesthesia and sedate. It lowers blood pressure and depresses breathing.
Updated 2026-11-01
Also called: 2,6-diisopropylphenol
The figure shows propofol bound to the human α1β2γ2 GABA-A receptor, with GABA present, at sites in the transmembrane domain between subunits.
Mechanism of action
Propofol is a highly lipid-soluble phenol supplied as a lipid emulsion. It binds the GABA-A receptor and lengthens the GABA-activated opening of the chloride channel. Neurons hyperpolarise and the patient loses consciousness within seconds. The effect of a bolus ends quickly by redistribution, and its rapid hepatic metabolism allows a clear-headed wake-up even after infusions.
- Reaches the brain in one circulation time
- Binds the GABA-A receptor and prolongs chloride channel opening
- Neurons hyperpolarise: hypnosis within seconds
- Redistribution and liver metabolism: rapid wake-up
Pharmacokinetics
- Distribution
- Rapid equilibration between plasma and brain, then redistribution to muscle and fat. With infusions over days it accumulates in tissues and waking is delayed.
- Metabolism
- Hepatic conjugation (glucuronide and others) to inactive metabolites.
- Elimination
- Kidney, as metabolites; urine may look green, a harmless effect.
- Onset and duration
- Unconsciousness in under a minute after a bolus; waking within minutes of stopping it.
Indications
- Induction and maintenance of general anaesthesia
- Procedural sedation and monitored anaesthesia care
- Sedation of intubated, ventilated ICU patients
Adverse effects
Common
- Pain in the vein on injection
- Hypotension
- Apnoea at induction
- Bradycardia
- Involuntary movements
- Green urine (harmless)
Contraindications
- Hypersensitivity to propofol or to a component of the emulsion (the label includes egg or soy allergy)
Key interactions
- Opioids, benzodiazepines and other central nervous system depressants
- Deeper sedation, apnoea and hypotension; lower doses are needed.
- Fentanyl in children
- Higher risk of bradycardia.
- Prior intravenous lidocaine
- Reduces injection pain.
What is monitored
- Continuous blood pressure, heart rate and rhythm
- Pulse oximetry and capnography; airway
- Depth of sedation
- With prolonged infusion: triglycerides, pH, lactate, potassium, CK and renal function
Administration and safety
- Strict aseptic technique: the lipid emulsion supports bacterial growth; each vial is for one patient only and is discarded on time together with the line.
- Shake before use and do not give if the emulsion looks separated.
- Use large forearm or antecubital veins to reduce pain.
- Given only by staff trained in airway management who are not performing the procedure.
Nursing care
- Before: airway equipment, oxygen and suction ready; record baseline blood pressure and saturation.
- During: watch breathing, saturation, capnography and blood pressure continuously.
- In the ICU: assess the level of sedation and neurological function daily to use the lowest effective dose.
- Count the emulsion's lipids within the nutritional intake and check triglycerides during long infusions.
- Report at once unexplained acidosis, dark urine from rhabdomyolysis or ECG changes.
Pregnancy and breastfeeding
No risk of birth defects has been identified; it crosses the placenta and can depress the newborn if used close to delivery.
Test yourself
Think of the answer, then tap the question to see it.
Which findings define propofol infusion syndrome?
Severe metabolic acidosis, hyperkalaemia, lipaemia, rhabdomyolysis, hepatomegaly, renal and heart failure, and Brugada-like ECG changes.
Why must an opened propofol vial be used promptly and for one patient only?
The lipid emulsion lets microorganisms grow; late or shared use has been linked to sepsis.
What is the most important cardiovascular effect of propofol at induction?
Arterial hypotension, from vasodilation and lower contractility, without marked compensatory tachycardia.
Why does a patient wake quickly after a bolus of propofol?
The drug redistributes from the brain to other tissues and is also metabolised rapidly by the liver.
Related drugs
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - PROPOFOL injection, emulsion (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 24 (McGraw Hill, 2023); eEML - Electronic Essential Medicines List (World Health Organization, 2025); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.