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International Association Against Painful Experiments on Animals

History of Animal Experiments

10: Animal Testing Side Effects Drugs

There is no doubt that animal tests have failed to predict many of the dangers of drug therapy. Occasionally, unforeseen side effects lead to a drug's withdrawal from the market. An analysis by scientists at the pharmaceutical companies Pfizer and Rhone-Poulenc revealed that at least 80 products have been withdrawn on safety grounds from one or more of four countries (France, West Germany, UK and the USA) between 1961 and July 1987. The most common adverse reactions which led to withdrawal were liver damage, blood disorders and neurological problems.(27)

Alternatively, unforeseen hazards lead to restrictions in the drug's use or there may be special warnings sent to doctors or published in the medical press. The problem is that drug side effects are thought to be very much under reported so the overall dangers of drug therapy are difficult to assess. For instance, the British system of monitoring drugs once they have reached the market has been established since the 1960s but is known to be inadequate with only 1-10% of side effects being reported.(28) Even very serious reactions, including drug-induced fatalities, are grossly under reported.(29) Nevertheless, the United States General Accounting Office found that 51.5% of drugs had to be relabelled due to "serious" unexpected side effects. The labelling changes either limited the drug's use or added major warnings or precautions.(56)

In the case of ICI's heart drug Eraldin, patients suffered intestinal and eye problems, including blindness, and there were many deaths. Ultimately ICI compensated more than 1000 victims, yet animal experiments had given no warning of the dangers which took four years to surface.30 Improved monitoring of patients would surely have identified the problem at an earlier stage. The arthritis drug Oraflex is one of several anti-inflammatory agents recently withdrawn on safety grounds. Deaths occurred mainly through liver damage but in the animals considered closest to us - non human primates - no evidence of toxicity could be seen at 7 times the maximum tolerated human dose for a year.(30)

 

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