Animal tests - necessary or not?

Many studies published in the scientific literature comparing drug side effects in humans and animals have found animal tests to be less predictive than tossing a coin. One review of human-animal correlation in drugs that had been withdrawn because of adverse reactions found that animal tests predicted the human side effects only six out of 114 times.

Hundreds of drugs to treat strokes (eg, Cerestat, MaxiPost, Zendra, Lotrafiban, gavestinel, nimodipine, clomethiazole) have been found safe and effective in animal studies and then injured or killed patients in clinical trials. Cigarette smoke, asbestos, arsenic, benzene, alcohol and glass fibres are all safe to ingest, according to animal studies. Of 22 drugs shown to have been therapeutic in spinal cord injury in animals, not one is effective in humans. Of 20 compounds known not to cause cancer in humans, 19 do cause cancer in rodents. Penicillin, the world’s first antibiotic, was delayed for more than 10 years by misleading results from experiments in rabbits, and would have been shelved forever had it been tested on guinea pigs, which it kills. Well, this is what some articles say. However, others say exactly the opposite. After all, all alternatives like a mathematical formula, a computer simulation, or cells growing in tissue culture are even more unlike humans than are laboratory animals, yet such models are often successfully used in research. And the claim that no species can be used as a model for a different species is also invalid. If this were the case, a veterinarian needing to treat an exotic animal such as a tiger, would have no drugs or anaesthetics available, because none have been developed in tigers for tigers. In fact, there are a wide range of anaesthetics, drugs and antibiotics that are available to zoo vets, provided that they are used with care. There are species differences in response, but these are relatively insignificant. The fact is that the continued use of animals is essential both to maintain human health by the production of vaccines and pharmaceuticals, and to support research into the many serious diseases that still plague society. What animal welfare organisations should be doing, and many are doing, is to develop alternatives that do not also put human lives at risk. The enormous contributions that animal research has made to our understanding of human biology and the development of medicine have been discussed elsewhere. All good scientists now accept that every animal experiment must be scientifically justified and the cost to the animal in terms of pain and/or distress assessed. If the estimated cost to the animal is large in relation to the potential benefits to humans, then the research should not be done. The use of animals to test cosmetics, for example, is already banned in the UK. The aim of this article is to show how animals (and alternatives) can be used to model humans, even though they may differ from humans in many ways.