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Galen, an influential physician from the second century, remarked of his clinical trial, “All who drink of this remedy recover in a short time, except those whom it does not help, who all die. Therefore, it is obvious that it fails only in incurable cases.” Unfortunately, error in contemporary clinical investigation of poisoning tends to be more insidious than the error in logic in Galen’s conclusion, and skillful scrutiny of published research remains an important endeavor.

Advances in medical toxicology are achieved through the scientific method, but must first rely on observations derived from xenobiotic exposures for hypothesis generation. Subsequent research questions are analyzed with epidemiological investigation, and preliminary studies are examined with methodological scrutiny. Initial analytical techniques are improved, and confirmatory studies are performed. Ultimately, models relating cause to effect are formulated.

To optimize patient care, it is useful to grade the quality of available scientific evidence used to justify treatment recommendations. Decisions about how strongly to recommend a medical action will be based on the careful consideration of the risks of leaving a patient untreated, the potential benefits and harms of treatment, the quality of the guiding evidence, a balanced view of resource utilization, and ultimately the values of the person to be treated. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) Working Group has provided a framework for assessing and communicating levels of scientific evidence (Table 137–1).26 An understanding of basic principles of research design and epidemiology is required to interpret published studies and to lay the groundwork for future investigation in toxicology.

TABLE 137–1GRADE System for Evaluating Clinical Recommendations


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