Sevoflurane

Indications

Sevoflurane is used for: General anaesthesia

Adult Dose

Inhalation Induction and maintenance of general anaesthesia Adult: Induction: Premedicated patient: Up to 5% v/v w/ oxygen (or mixture of oxygen and nitrous oxide), individualised according to age and clinical status. Unpremedicated patient: Up to 8% v/v. Maintenance: 0.5-3% v/v w/ or w/o nitrous oxide. Doses are given via calibrated vaporiser.

Child Dose

Inhalation Induction and maintenance of general anaesthesia Child: Induction: Up to 7% v/v w/ oxygen (or mixture of oxygen and nitrous oxide) given via calibrated vaporiser.

Renal Dose

Administration

Contra Indications

Known or suspected susceptibility to malignant hyperthermia. Previous hypersensitivity.

Precautions

Patient w/ increased intracranial pressure, neuromuscular disease (esp Duchenne muscular dystrophy), mitochondrial disorders. Patient who are hypovolaemic, hypotensive, haemodynamically compromised, at risk of QT prolongation. Hepatic and renal impairment. Childn. Pregnancy and lactation. Patient Counselling May impair ability to drive or operate machinery. Monitoring Parameters Monitor for BP, temp, heart rate and rhythm, oxygen saturation, end-tidal CO2, and end-tidal drug concentrations prior to and throughout anaesthesia. Monitor the temp of CO2 absorbent canister. Recovery from general anaesthesia should be assessed carefully before discharge. Lactation: excreted in breast milk; no adverse effect on nursing infant

Pregnancy-Lactation

Pregnancy There are no adequate and well-controlled studies in pregnant women; in animal reproduction studies, reduced fetal weights were noted following exposure to 1 MAC sevoflurane for three hours a day during organogenesis There are no data on pregnancy exposures in primates corresponding to periods prior to the third trimester in humans Sevoflurane has been used as part of general anesthesia for elective cesarean section in women; there were no untoward effects in mother or neonate; the safety of sevoflurane in labor and delivery has not been demonstrated Lactation The concentrations of sevoflurane in milk are probably of no clinical importance 24 hours after anesthesia; because of rapid washout, sevoflurane concentrations in milk are predicted to be below those found with many other volatile anesthetics

Interactions

May enhance effect and duration of competitive neuromuscular blockers. Metabolism and toxicity increased by cytochrome P450 isoenzyme CYP2E1 inducers including isoniazid and alcohol. Increased risk of cardiac arrhythmias when used with epinephrine or norepinephrine.

Adverse Effects

Side effects of Sevoflurane : Cardiorespiratory depression, hypotension, bradycardia; laryngospasm, increased cough and salivation; urinary retention, acute renal failure, changes in liver enzyme values, liver damage; nausea, vomiting, delirium, seizure; rash, urticaria, pruritus, dyspnoea, wheezing, chest discomfort, bronchospasm, anaphylactic/anaphylactoid reaction; agitation, dystonic movements (childn). Potentially Fatal: Malignant hyperthermia. Rarely, hyperkalaemia resulting in cardiac arrhythmias, particularly in childn w/ neuromuscular disease.

Mechanism of Action

Sevoflurane is a volatile halogenated general anaesthetic which causes a reversible loss of consciousness and pain sensation, suppression of voluntary motor activity, modification of autonomic reflexes, depression of the respiratory and CV systems. It also has muscle relaxant properties.