Animal testing - Dangerous to human health

Overwhelming evidence demonstrates that animal tests are dangerous to human health, and may be the reason that so many 'safety tested' drugs cause so many side effects.

Animal testing doesn't work.

Its results are often inconclusive and cannot be accurately extrapolated to humans. As a result, relying on the results of animal testing can be dangerous to human health. It is a system which is long overdue for a critical review, and yet no such review is on the horizon.

In his seminal book, the Naked Empress: The Great Medical Fraud (Switzerland: CIVIS, 1992) eminent researcher Hans Ruesch notes that approximately 15,000 new drugs are marketed every year, while some 12,000 are withdrawn. According to the Food and Drug Administration (FDA), 1.5 million Americans were hospitalised in 1978 alone as a consequence of pharmaceutical drugs administered to "cure" them. A further 30 per cent of all hospitalised people suffered further damage from the therapy prescribed to them. In the 1990s, studies show that 180,000 medically induced deaths occur each year in the USA (JAMA, 1994; 23: 1851). Of course a percentage of these are due to incorrect prescription and administration of drugs, but it still begs the question: how safe are the "safety tested" drugs we use?

Although our scientists argue that there are no real alternatives, this attitude is changing. To be helpful to human beings, drugs should be tested using human tissues, cells and organs (known as in vitro cultures). Chromatography and mass spectrometry, which separate drug substances at their molecular level to identify their properties, and quantum pharmacology, using quantum mechanics to understand the molecular structure of chemicals, are also viable means of testing drugs.

More importantly, properly carried out human clinical trials and thorough reporting of drug side effects by post marketing surveillance are urgently needed. The AMES (in vitro test used to identify the presence of toxins) test used in conjunction with other in vitro tests can be very effective in determining carcinogenic (cancer causing) and teratogenic (ability to cause birth defects) properties of substances. And yet these methods are not widely used. Consequently, researchers are unfamiliar with them and resistant to the idea of new training. Because they are not widely used, they are more expensive. Because they are more expensive, they are not widely funded. The truth is that animal testing is the bargain basement of medicine. And we're getting what we pay for.

To counter this situation, many committed organisations have tried to alert the public to what is first and foremost the inhumanity of these tests. However, it is doubtful whether, in a culture that doesn't take the concept of human rights all that seriously, the concept of animal rights will ever be given much priority. Under the very broad umbrella of "animal rights", there are now groups who believe that, by clinging to the idea of animals' moral rights and using methods of emotional blackmail or even outright violence to get its message across, the movement has continually shot itself in the foot. These few argue that in a climate which is increasingly calling for evidence based medicine, the case for what is known as the "three Rs" reducing, refining and replacing animal testing can be convincingly argued and won through levelheaded analysis of the scientific research.

There is no doubt that there is copious evidence from the fields of vaccination, cancer, heart disease, stomach ulcers and sudden infant death to show that animal testing does not work. That more scientists and medical researchers have not cottoned on to this fact is surprising. Indeed, the debates in the medical press have been lacklustre to say the least, with pro vivisectionists relying on tradition (what was good enough for Galen is good enough for us JAMA, 1989; 262: 2716-20); heroism (millions of lives have been saved because of animal testing JAMA, 1990; 264: 2564-6); and even paranoia (animal activists are "politically shrewd" and have more money than we do, which isn't fair N Eng J Med, 1991; 324: 1640-3).

Anti vivisectionists, on the other hand, have tried to remain levelheaded in print to an extent that they fail to make their point forcefully enough (Lancet, 1994; 343: 902-5). A few, like Dr Peter Mansfield, president of Doctors in Britain Against Animal Experiments, speak plainly: "The pharmaceutical industry has products to sell and under the law as it stands needs animal experiments to help them do it. They say we need animal experiments for the advancement of medical science, but it is the future of their industry that really concerns them."

To date, much of the most convincing evidence against animal testing has been independently compiled by antivivisectionist individuals and groups. There remains, however, a long standing difficulty in trying to get research which contradicts the current enthusiasm for animal testing published in major medical journals. Whether this is through the diffidence of the major publishers, which are forced by commercial concerns to consent to and uphold these views, is unclear.

A quick flick through any major journal shows that as surely as women's magazines rely on advertising from cosmetics companies, medical journals rely on the advertising money of major pharmaceutical companies. This will have a bearing on the vetting system for research articles. As a result, much of the evidence ends up in books and newsletters.

Poor Predictability

Many of the most common life threatening side effects of drugs cannot be predicted by animal tests. Animals, for instance, cannot let the experimenter know if they are suffering from headache, amnesia, nausea, depression and other psychological disturbances. Allergic reactions, some blood disorders, skin lesions and many central nervous system effects are even more serious examples that cannot be demonstrated by animal models (Sharpe, The Cruel Deception: The Use of Animals in Medical Research, Thorsons, 1988).

Given the large variety of laboratory animals available, and the widely varying laboratory conditions under which experiments are carried out, it should come as no surprise that the results of animal testing can be used to prove or disprove almost anything. Indeed it is this "flexibility" of animal testing which makes it so appealing to researchers and drug companies.

This is especially true in the field of cancer research. Saccharin provides a good everyday example. To this day it remains on sale, because it appears only to cause bladder cancer in male rats. The contraceptive was banned in the US over 20 years ago on the basis that it caused cancer in dogs and baboons. Yet the FDA recently lifted the ban on the basis of two studies, from New Zealand and the World Health Organization (WHO), which both concluded that the contraceptive did not heighten cancer risk. Ironically, soon after the FDA gave its seal of approval, a closer analysis of these studies revealed that the risk in fact doubles in the first five years of taking the hormone and then drops to almost nothing after that (JAMA, March 8, 1995).

An even more bizarre example is the drug tamoxifen, used to treat human breast cancer by blocking the production of oestrogen. Although tamoxifen reduces the incidence of mammary cancer in rodents, it actually increases the incidence of liver cancer in them (J Nat Cancer Inst, 1991; 83: 1450-59). From these studies, one would conclude that the drug is toxic to the kidneys. However, in human subjects, tamoxifen has been shown to cause uterine cancer (JAMA, 18 May 1994). Studies put the risk in humans between two and six times that of controls (Lancet, 19 February, 1994; Lancet, 1989, i: 117-20).

Although the stated rationale behind animal testing is that it is done for the greater good of mankind, there is a strong argument that really it is done for legal rather than scientific reasons. Performing the necessary animal experimentation serves as a legal alibi for corporations when their products damage or kill those who use them.

Thalidomide, recently re approved by the FDA, is a classic example. During the lengthy trial of the manufacturers in 1970, numerous court witnesses, all animal experimenters, stated under oath that the results of animal experiments are never 100 per cent valid for human beings. However, because the manufacturers performed the required animal safety tests, and because these tests did not show any evidence of danger, the manufacturers of thalidomide were found not guilty by the court of consciously making a harmful drug.

As Robert Sharpe points out, "In pregnant animals, differences in the physiological structure, function and biochemistry of the placenta aggravate the usual differences in metabolism, excretion, distribution and absorption that exists between species and make reliable predictions impossible." In the animal testing of thalidomide, the grotesque malformations caused by the drug in humans proved impossible to replicate.

In his book Drugs as Teratogens (quoted in Drugs and Pregnancy: Human Teratogens and Related Problems, D F Hawkins (ed), Churchill Livingstone, 1983), J L Scharden comments: "In approximately 10 strains of rats, 15 strains of mice, eleven breeds of rabbit, two breeds of dogs, three strains of hamsters, eight species of primates and in other such varied species as cats, armadillos, guinea pigs, swine and ferrets in which thalidomide has been tested, teratogenic effects have been induced only occasionally."

After the trial, the animal testing lobby tried to say that thalidomide was a "rare exception" and that this tragedy "emphasises a need for more rigorous animal testing, not less."

Medical historian Hans Ruesch takes up the story in his own book: "Only when the white New Zealand rabbit was tested, a few malformed rabbit babies were obtained, and subsequently also some malformed monkeys after years of tests (with increasing doses), hundreds of different strains and millions of dead animals used. But researchers immediately pointed out that malformations, like cancer, could be obtained by administration of practically any substance in high concentration, including sugar and salt, which will eventually upset the organism, causing trouble."

Animal testing also has an abysmal record in developing useful drugs to combat the effects of stroke (Stroke, 1990; 21: 1-3). Following experiments on rabbits, dogs, gerbils and monkeys, animal researchers suggested that barbiturates could protect against the effects of stroke. In human stroke victims, however, barbiturates had little or no protective effect (see R Sharpe, Science on Trial, Awareness Publishing, 1994). By contrast, the drug nimodipine has shown some effect on specific kinds of stroke namely sub arachnoid haemorrhage (though not without several unpleasant side effects such as hypotension, headache and nausea). But the animal data on the drug are inconsistent and conflicting; in cats and baboons, for instance, nimodipine produced no overall beneficial effect (Stroke, 1986; 17: 884-90). Today, we know that gastric ulcers are mainly caused by the bacteria Helicobactor pylori. However, use of animal models to develop effective drug treatment may have delayed this discovery by as much as 100 years.

For decades, building on experiments of the gastric secretions of dogs, researchers began cutting the vagus nerve to treat stomach ulcer patients. It was believed that if the acid in digestive juice could be reduced, ulcers would be cured. This theory flew in the face of the knowledge, even in the late 19th century, that the digestive action of the stomach lay in an enzyme called pepsin, and not in acid itself (OH Wangensteen, et al, The Rise of Surgery, W M Dawson & Sons, 1978).

Sometime after the 1940s, the role of the vagus nerve of animals was soon discovered to be different from humans, especially dogs the very species on which the technique was originally developed. Nevertheless experimentation continued, and the canine model, and eventually its equivalent in rats, was used to develop drugs which would reduce stomach acid secretions. These drugs include those acting upon the histamine system, such as cimetidine or the proton pump inhibitors like omeprazole, which act upon another stomach enzyme. It took until the 1980s for researchers to discover the H pylori bacterial connection.

False Patterns of Disease

The fact that the laboratory animal is relatively healthy before the experiment means that disease and or trauma has to be induced by artificial and often violent means. This bears no relation whatsoever to the spontaneous ways in which humans develop illness, often through faulty lifestyle and diet.

Consider the case of osteoarthritis, a human degenerative disease resulting in painful deformities of the joints. In order to mimic human lameness in dogs, cats, sheep and pigs, researchers beat the joints of animals with hammer blows, inject them with irritating liquids, subject them to ionising radiation and/or dislocate them. Of course, the resulting fractures, haemorrhages, thromboses, contusions) and inflammations bear no relation to human osteoarthritis. Drugs which are then tested on such artificially diseased, non human animals cannot possibly yield results relevant to a spontaneously occurring human disease.

Better drugs, not more drugs

Clearly we don't need as many drugs as there are in the marketplace. Indeed, in 1981, the United Nations Industrial Development Organisation, in collaboration with the WHO, published a list of only 26 drugs, from the 205,000 on the market, which were considered "indispensable", with nine of these being considered more indispensable than others (quoted in H Ruesch, Naked Empress).

According to Peter Mansfield, it is "by luck, rather than good judgement" that we have, over the past thirty years, stumbled upon many useful drugs which have a known range of safety and danger, and which "will continue to be used in appropriate and well defined circumstances." But while there will be a continued need for drugs, Mansfield envisages a day when the whole paradigm of medical care will change.

"Science is really a method for answering questions. If we ask a stupid question, scientific methods will faithfully produce for us a stupid answer. We must debate carefully, therefore, what questions we ask our scientists to tackle.

"The drug industry can be relied on to ask for the best drug solution to each medical problem. We must broaden the question: what is the best solution overall? Sometimes it may be a drug, more usually not. A drug may relieve the pain and inflammation of displaced muscles and joints, but only a manipulative treatment stands any chance of curing it. Diet offers major benefits in dealing with rheumatism, which drugs cannot improve in the long run. The likelihood is that drugs will retain a major part in the first aid treatment of many diseases, but that other methods will offer better chances of long term benefit and prevention of relapse."

There is an alternative to animal research and it's called good science.

!APat Thomas