The molecular basis of halothane-induced hepatitis.

Halothane hepatitis The anaesthetic agent halothane (CF,CHCIRr) causes two distinct types of liver damage. About 20% of halothane-exposed patients exhibit mild hepatotoxicity, characterized by transient elevations in liver enzymes. In contrast, a much smaller fraction of patients exposed to halothane (between 1 in 3500 and 1 in 35 000) develop severe hepatotoxicity, commonly termed ‘halothane hepatitis’, which frequently may progress to liver failure and death [ 11. Typically, patients with halothane hepatitis tend to be obese females in late middle age, although a minority of patients are not obese, some are male and the syndrome has been described in children [2]. In common with many other adverse drug reactions which are of clinical importance, halothane hepatitis is idiosyncratic and dose-independent. The underlying pathogenic mechanisms have yet to be resolved unequivocally, although various clinical and laboratory findings indicate that immune processes are involved [ 11. A series of recent investigations have outlined a likely mechanism, which involves an immune response to a group of novel, halothane metabolite-modified liver protein antigens.