International Association Against Painful Experiments on Animals

101 Misleading results from Vivisection Animal Experiments

16: Animal Tests Confuse Painkiller Probe

Since 1953 when doctors first drew attention to the kidney damage associated with prolonged use of combination painkillers, there have been many animal experiments to try and clarify the effects seen in people.(1) In fact, these have only obscured the issue. For example, interest centered on which ingredient was responsible, and although suspicion naturally fell on phenacetin since this was present in most analgesic mixtures, the characteristic kidney damage seen in patients could not be reproduced in animals.(1)

The experiments also suggested that aspirin rather than phenacetin was to blame in painkillers containing the two drugs.(2) This is because, unlike phenacetin, aspirin readily induces kidney damage in laboratory animals. Eventually, human studies showed that phenacetin was indeed a major culprit.(3)

So contradictory were the experiments that a major analysis of the subject concluded that if doctors had not first observed the effects in patients, they would never have been suspected, foreseen or predicted by animal tests.(1) Phenacetin was finally withdrawn in 1980 when there were also suspicions that it caused cancer.


I) I.Rosner, CRC Critical Reviews in Toxicology, 1976, vol.4, 331-352.
2) British Medical Journal, 1970, October 17, 125-126.
3) K.G.Koutsaimanis & H.E. de Wardener, British Medical Journal, 1970, October 17, 131-134.

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