Pharmacokinetics: Interactions of new drugs and the human body (Reprinted from Clinical Research in Pharmaceutical Development, vol 75, pg 109-124, 1996)

A new drug is only as good as it proves itself to be once it is studied in humans. Theoretical calculations and animal models are used only as predictors of how a drug will act once it gets into the body. The extensive animal safety testing that is performed for a new product is designed to weed out drugs that may cause acute poisoning, lead to long-term toxicities, or present an undesirable number of adverse effects. By the time a drug is first used in people, there is a reasonable assurance that the product will be safe. There are, of course, no absolute guarantees. Many drug entities have made it to the Phase 1 trials, only to be pulled from further consideration because of information discovered during this phase.