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Pharmacology · Inhaled anaesthetics

Sevoflurane !

Inhaled anaesthetic with a mild smell and fast effect, ideal for putting children to sleep by mask. It can trigger malignant hyperthermia.

Updated 2026-11-01

  • Class: Inhaled anaesthetics
  • Target: Several central nervous system ion channels (GABA-A and glycine receptors, potassium channels)
  • ATC code: N01AB08
  • WHO Model List of Essential Medicines

Also called: Sevofluorane

Mechanism of action

Sevoflurane is vaporised and inhaled; it passes from the alveoli into the blood and then the brain. It enhances inhibitory receptors (GABA-A and glycine) and modulates other channels, depressing neuronal activity: unconsciousness, amnesia and immobility. Because it is poorly soluble in blood, its brain concentration rises and falls quickly when the vaporiser setting changes.

  1. Vaporised and inhaled down to the alveoli
  2. Poorly soluble in blood: brain concentration rises fast
  3. Enhances inhibitory receptors and depresses neurons
  4. Removed by the lungs when the vaporiser is turned off

Pharmacokinetics

Absorption
Through the lungs; low blood solubility allows fast induction and emergence.
Metabolism
A small fraction is metabolised in the liver by CYP2E1, releasing inorganic fluoride.
Elimination
Almost all is exhaled unchanged.

Indications

  • Mask induction of general anaesthesia, especially in children
  • Maintenance of general anaesthesia in adults and children

Adverse effects

Common

  • Concentration-dependent hypotension
  • Respiratory depression
  • Postoperative nausea and vomiting
  • Emergence agitation in children
  • Cough and laryngospasm (uncommon)

Contraindications

  • Known or suspected genetic susceptibility to malignant hyperthermia
  • Hypersensitivity to sevoflurane or other halogenated agents

Key interactions

Non-depolarising neuromuscular blockers
Enhances and prolongs the block.
Suxamethonium
Higher risk of malignant hyperthermia.
Epinephrine
Higher risk of ventricular arrhythmias.
Nitrous oxide, opioids and benzodiazepines
Reduce the amount of sevoflurane needed (lower MAC).
Isoniazid and chronic alcohol use
Induce CYP2E1 and increase its metabolism.

What is monitored

  • End-tidal agent concentration and anaesthetic depth
  • Blood pressure, ECG and saturation
  • End-tidal CO2 and temperature (signs of malignant hyperthermia)
  • Agitation on emergence

Administration and safety

  • Only with a calibrated vaporiser specific for sevoflurane.
  • Change the CO2 absorbent if it may be dry: with a desiccated absorbent, heat, smoke and degradation products form.
  • Keep dantrolene available where it is used.

Nursing care

  • Before: ask about personal or family history of malignant hyperthermia and myopathies.
  • In recovery: watch breathing, saturation, nausea and agitation as the child wakes.
  • If high fever, rigidity, tachycardia or rising CO2 appear during anaesthesia: report at once.
  • Warn that the ability to drive or operate machinery may be reduced after anaesthesia.

Pregnancy and breastfeeding

It relaxes uterine smooth muscle and can contribute to uterine atony and bleeding. Animal studies show developmental effects with long exposures.

Test yourself

Think of the answer, then tap the question to see it.

Why does sevoflurane allow fast induction and emergence?

Because of its low blood solubility: alveolar, blood and brain partial pressures reach equilibrium quickly.

What is compound A?

A degradation product of sevoflurane in the CO2 absorbent, potentially nephrotoxic, which increases with low fresh gas flows.

Which signs suggest malignant hyperthermia during sevoflurane anaesthesia?

Unexplained rise in end-tidal CO2, tachycardia, muscle rigidity (for example of the masseters), hyperthermia, acidosis and hyperkalaemia.

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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 - SEVOFLURANE liquid (DailyMed (U.S. National Library of Medicine), 2026); Malignant hyperthermia: MedlinePlus Genetics (MedlinePlus (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 24 (McGraw Hill, 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.