Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2019 Publisher: Piramal Critical Care Limited, Suite 4, Ground Floor, Heathrow Boulevard East Wing, 280 Bath Road, West Drayton, UB7 0DQ, United Kingdom
Isoflurane is general inhalation anaesthetic for use in induction and maintenance.
MAC values for Isoflurane vary with age. The table below indicates average MAC values for different age groups.
ADULTS*:
| AGE | Average MAC value | |
|---|---|---|
| In 100% Oxygen | 70% N2O | |
| 26 ± 4 years | 1.28% | 0.56% |
| 44 ± 7 years | 1.15% | 0.50% |
| 64 ± 5 years | 1.05% | 0.37% |
PAEDIATRIC POPULATION:
| Age | Average MAC Value in 100% Oxygen |
|---|---|
| Preterm neonates <32 weeks gestational age | 1.28% |
| Preterm neonates 32-37 weeks gestational age | 1.41% |
| 0-1 month | 1.60% |
| 1-6 months | 1.87% |
| 6-12 months | 1.80% |
| 1-5 years | 1.60% |
Premedication drugs should be selected according to the needs of the patient. The respiratory depressant effect of Isoflurane should be taken into account. The use of anticholinergic drugs is a matter of choice, but may we advisable for inhalation induction in paediatrics.
As Isoflurane has a mild pungency, inhalation should usually be preceded by the use of a short acting barbiturate, or other intravenous induction agent, to prevent coughing. Alternatively, Isoflurane with oxygen or with an oxygen/ nitrous oxide mixture may be administered.
It is recommended that induction with Isoflurane be initiated at a concentration of 0.5%. Concentrations of 1.5-3.0% usually produce surgical anaesthesia in 7-10 minutes.
Isoflurane is not recommended for use as an inhalation induction agent in infants and children because of the occurrence of cough, breath-holding, desaturation, increased secretions and laryngospasm (see section 4.4).
Adequate anaesthesia for surgery may be sustained with an inspired Isoflurane concentration of 1.0% to 2.5% in an oxygen/nitrous oxide mixture. Additional Isoflurane (0.5% to 1.0%) may be required when Isoflurane is given with oxygen alone.
For caesarean section, 0.5-0.75% isoflurane in a mixture of oxygen/nitrous oxide is suitable to maintain anaesthesia for this procedure.
Arterial pressure levels during maintenance tend to be inversely related to alveolar Isoflurane concentration in the absence of other complicating factors. Provided there are no other complicating factors this is probably due to peripheral vasodilation. Excessive falls in blood pressure may be due to the depth of anaesthesia and, in such circumstances, can be corrected by reducing the inspired Isoflurane concentration.
As with other agents, lesser concentrations of isoflurane are normally required to maintain surgical anaesthesia in elderly patients. See above for MAC values related to age.
Vaporisers specially calibrated for Isoflurane should be used so that the concentration of anaesthetic can be accurately controlled.
Isoflurane is not recommended as an induction agent in children.
As with other halogenated anaesthetics, hypotension and respiratory depression have been observed. Close monitoring of blood pressure and respiration is recommended. Supportive measures may be necessary to correct hypotension and respiratory depression resulting from excessively deep levels of anaesthesia.
5 years.
Do not store above 30°C. Keep the container tightly closed. Keep out of the sight and reach of children.
Amber glass Type III nominal 100 ml or 250 ml bottle with black screw cap and polyethylene cone.
Vaporisers specially calibrated for isoflurane should be used so that the concentration of anaesthetic delivered can be accurately controlled.
It is recommended that vapour from this and other inhalation agents be efficiently extracted from the area of use.
Any unused medicinal product or waste material should be disposed of in accordance with local requirements.
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