Animals are used in pharmacology because there is no practical alternative for studying the effects of new drugs on the living body (Letters, THES , September 7, 14). Alternative in vitro testing offers qualitatively different information.

As a pharmacologist, I have seen how drugs have various effects on in vitro systems but have quite different effects on intact living humans or animals.

There are many possible (often unpredictable) modifying effects of the cardiovascular, endocrine and central nervous systems on a drug's primary action. Put bluntly, the only way to know with certainty what a drug will do to an intact human is to administer it to an intact human, but to do so in ignorance would be dangerous and illegal. Thus animal models are used.

Global regulatory bodies insist that any drug must pass a battery of animal and in vitro tests before human use. Remove either the animal or the in vitro testing from this scheme and new drug development, not entirely risk free, becomes substantially riskier.

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It is false that drug companies waste hundreds of millions of dollars because they cannot consider alternatives to animal research. They can, by law they must, and they do.

The claim that animal models do not predict the human response often does not hold true. The effective anti-glaucoma drug Latanoprost, working to preserve the eyesight of many people who may otherwise go blind, is one example.

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I am involved in the investigation of alternatives to live animal research and applaud the many recent developments. Also commendable is the rigorous British system that regulates, through veterinary, medical and scientific panels, animal research and researchers. But we are not ready to dispense with animal research altogether and it may be a long time yet before we are, if ever.

Cameron Millar
University of Luton