Sevoflurane is not pungent, so it can be used for inhalation induction e.g. in children. Anaesthesia can be achieved within two minutes. The minimum alveolar concentration (MAC) which results in 50% of patients not responding to a skin incision decreases with age. The MAC is also reduced by giving sevoflurane with nitrous oxide.
The drug is eliminated by exhalation. Adults usually emerge from anaesthesia in 8 minutes, slightly faster than with isoflurane.
Approximately 5% of the sevoflurane absorbed is metabolised. This results in the release of inorganic fluoride with concentrations usually peaking within two hours, but taking up to two days to return to baseline. This may potentially reduce the urine concentrating power of the kidneys. Metabolism does not produce trifluoracetic acid, which may be responsible for the adverse effects of halothane on the liver.
A degradation product (Compound A) results from sevoflurane coming into contact with CO2 absorbants in the anaesthetic circuit. Although Compound A may not reach concentrations that are deleterious to humans, it is nephrotoxic in rats. Sevoflurane is contraindicated in anaesthetic equipment employing rebreathing circuits which contain Baralyme.
Like other inhaled anaesthetics, sevoflurane causes cardio respiratory depression; hypotension and bradycardia occur commonly. Other frequent adverse effects include agitation, breath-holding and laryngospasm during induction, and coughing, nausea and vomiting during recovery. Malignant hyperthermia may be triggered in susceptible patients.
Sevoflurane reacts with other drugs used in anaesthesia e.g. neuromuscular blocking agents and opioids. Dose adjustments are required.
At present, it is not clear if sevoflurane is any better overall than similar anaesthetic drugs.
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