Halothane is a volatile anaesthetic gas, with many advantageous properties:
- potent at relatively low concentration
- smooth induction
- non-irritant
- pleasant to inhale
- causes bronchodilation
However, its use has declined as a result of a number of disadvantages:
- associated with severe hepatotoxicity:
- severity of hepatotoxicity is increased by repeated exposure
- halothane should not be used within 3 months of previous exposure
- if the patient has had any episode of jaundice or pyrexia with halothane, it must never be administered again
- in some series it accounts for some 5% of acute hepatic failure
- associated with cardiorespiratory depression, peripheral vasodilatation and sensitisation of the myocardium to catecholamines - elevated risk of arrhythmias
- little analgesia or muscular relaxation
- can imitate malignant hyperpyrexia