International Association Against Painful Experiments on Animals

101 Misleading results from Vivisection Animal Experiments

20: Doctors Warned about Halothane Liver Toxicity

Halothane was introduced into clinical practice in 1956 and immediately hailed as a great advance in anaesthesia. Unfortunately, the anaesthetic was soon found to harm the liver and within 5 years, at least 350 cases of "halothane hepatitis" had been recorded. The condition sometimes proves fatal and between 1964 and 1985, 180 British deaths were linked to the drug.(1)

The original animal tests had shown no evidence of liver damage,(2) and “early attempts to produce an animal model of halothane hepatitis proved disappointing,” according to anaesthetists at Edinburgh's Royal Infirmary.(3) Nevertheless, there has been no shortage of experiments: since 1976 five "animal models" have been described though “their application to humans is of doubtful significance.” (3)

By 1986, when Britain's Committee on Safety of Medicines strengthened the warnings of liver toxicity in human patients, (4) it was still not clear whether the same injuries could be induced in animals.(5)


1) British Medical Journal, 1986, April 5, 949.
2) Anaesthesiology, 1963,vol.24, 109-110.
3) D.C.Ray & G.B.Drummond, British Journal of Anaesthesia, 1991, vol.67, 84-99.
4) Scrip, 1987, October 2, 2.
5) C.E.Blogg, British Medical Journal, 1986, June 28, 1691-1692.

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