International Association Against Painful Experiments on Animals

101 Misleading results from Vivisection Animal Experiments

38: Animal-Testes Arthritis Drugs Killed Thousands

Phenylbutazone (Butazolidine) was once widely employed for the treatment of arthritis but reports of aplastic anaemia, an often fatal blood disease caused by damage to the bone marrow, led to the drug's withdrawal in some countries and to its restriction in others, notably America, France and the UK.(1)

On the basis of animal tests, phenylbutazone had seemed a safe drug with no toxic effects observed in rats even after administration of 5-10 times the dose used for people.(2) In particular, phenylbutazone's harmful effect on the bone marrow had not been predicted,(3) and one year after marketing, researchers noted that "there have been no published reports of serious effects...on the hemopoietic (blood forming) the experimental animal."(4) Later research showed that the dangers could be identified by test-tube experiments with human bone marrow cells.(5)

It has been estimated that phenylbutazone and oxyphenbutazone, a closely related drug that also causes aplastic anaemia, have been reponsible for 10,000 deaths worldwide.(6) Oxyphenbutazone (Tanderil) was withdrawn altogether in 1985.


1) C.Spriet-Pourra & M.Auriche, Drug Withdrawal from Sale (PJB Publications, 1988).
2) C.Hinz & L.M.Gaines, Journal of the American Medical Association, 1953, vol.l51, 38-39.
3) R.Heywood in Animal Toxicity Studies: Their Relevance for Man, Eds. C.E.Lumley & S.R.Walker (Quay Publishing, 1990).
4) O.Steinbrocker et al, Journal of the American Medical Association, 1952, November 15,
5) C.S.Smith et al, Biochemical Pharmacology, 1977, vol.26, 847-852.
6) Estimate by Dr Sidney Wolfe in Lancet, 1984, February 11, 353.

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