DOSAGE AND ADMINISTRATION

Premedication should be selected according to the need of the individual patient, and at the discretion of the anaesthetist.

Surgical Anaesthesia : SEVOFLURANE should be delivered via a vaporiser specifically calibrated for use with sevoflurane so that the concentration delivered can be accurately controlled. MAC (minimum alveolar concentration) values for SEVOFLURANE decrease with age and with the addition of nitrous oxide.

Induction : Dosage should be individualised and titrated to the desired effect according to the patient's age and clinical status. A short acting barbiturate or other intravenous induction agent may be administered followed by inhalation of SEVOFLURANE. Induction with SEVOFLURANE may be achieved in oxygen or in combination with oxygen-nitrous oxide mixtures. In adults inspired concentrations of up to 5% SEVOFLURANE usually produce surgical anaesthesia in less than 2 minutes. In children, inspired concentrations of up to 7% SEVOFLURANE usually produce surgical anaesthesia in less than 2 minutes. Alternatively, for induction of anaesthesia in unpremedicated patients, inspired concentrations of up to 8% SEVOFLURANE may be used.

Maintenance : Surgical levels of anaesthesia may be sustained with concentrations of 0.5 - 3% SEVOFLURANE with or without the concomitant use of nitrous oxide.

Emergence : Emergence times are generally short following SEVOFLURANE anaesthesia. Therefore, patients may require early post-operative pain relief. Older people: MAC decreases with increasing age. The average concentration of SEVOFLURANE to achieve MAC in an 80 year old is approximately 50% of that required in a 20 year old.

CONTRAINDICATIONS

SEVOFLURANE should not be used in patients with known or suspected sensitivity to SEVOFLURANE or other halogenated anaesthetics (e.g. history of liver function disorder, fever or leucocytosis of unknown cause after anaesthesia with one of these agents). SEVOFLURANE is also contraindicated in patients with known or suspected genetic susceptibility to malignant hyperthermia.

SEVOFLURANE is contraindicated in patients in whom general anaesthesia is contraindicated.

WARNINGS AND PRECAUTIONS

SEVOFLURANE may cause respiratory depression, which may be augmented by narcotic premedication or other agents causing respiratory depression. Respiration should be supervised and if necessary, assisted.

SEVOFLURANE should be administered only by persons trained in the administration of general anaesthesia. Facilities for maintenance of a patent airway, artificial ventilation, oxygen enrichment and circulatory resuscitation must be immediately available.

The concentration of SEVOFLURANE being delivered from a vaporiser must be known exactly. As volatile anaesthetics differ in their physical properties, only vaporisers specifically calibrated for SEVOFLURANE must be used. The administration of general anaesthesia must be individualised based on the patient's response. Hypotension and respiratory depression increase as anaesthesia is deepened.

INTERACTIONS

Beta-sympathomimetic agents like isoprenaline and alpha- and beta- sympathomimetic agents like adrenaline and noradrenaline should be used with caution during SEVOFLURANE narcosis, due to a potential risk of ventricular arrhythmia.

Non-selective MAO-inhibitors: Risk of crisis during the operation. It is generally recommended that treatment should be stopped 2 weeks prior to surgery. SEVOFLU RAN E may lead to marked hypotension in patients treated with calcium antagonists, in particular dihydropyridine derivates.

Caution should be exercised when calcium antagonists are used concomitantly with inhalation anesthetics due to the risk of additive negative inotropic effect.

Concomitant use of succinylcholine with inhaled anesthetic agents has been associated with rare increases in serum potassium levels that have resulted in cardiac arrhythmias and death in pediatric patients during the post-operative period. SEVOFLURANE has been shown to be safe and effective when administered concurrently with a wide variety of agents commonly encountered in surgical situations such as central nervous system agents, autonomic drugs, skeletal muscle relaxants, anti-infective agents including aminoglycosides, hormones and synthetic substitutes, blood derivatives and cardiovascular drugs, including epinephrine.