Drug Toxicity

Physicians prescribe drugs to prevent or treat disease. Those same drugs can be toxic to certain patients, however, because of genetic predisposition, nonselective action, or inappropriate use or administration of the drug. The United States Food and Drug Administration (FDA) spends a significant portion of its $1 trillion budget to ensure that new drugs are not overtly or unnecessarily dangerous. Moreover, pharmaceutical and biotechnology companies spend years and millions of dollars in clinical trials to understand the safety and inherent toxicity of their drugs. Potential drug candidates often fail because of unacceptable levels of toxicity in preclinical experiments or in clinical studies (see Chapter 48, Drug Discovery and Preclinical Development, and Chapter 49, Clinical Drug Evaluation and Regulatory Approval). Despite all of these efforts, even common over-the-counter drugs such as acetaminophen can be lethal (in this case, by causing fulminant hepatitis) if taken in supratherapeutic doses. It must be recognized that no drug is entirely specific. All drugs have both primary intended effects and secondary unintended effects, the latter known as side effects or ad-