Detection of adverse reactions during clinical trials requires careful and systematic evaluation of study participants before, during, and after drug exposure. Objective data must be gathered to determine that study subjects meet all inclusion criteria and do not have any conditions that preclude their participation. Standard laboratory and diagnostic tests are used to establish patients' baseline health and functional status. Such tests should be appropriate for the drug and condition under investigation and should be conducted at predetermined intervals.
Typically, serum chemistries and renal, hepatic, hematologic, electrolyte, and mineral panels are included. A complete medical history (including a review of all body systems) and physical examination and a complete medication history (including allergies and intolerances) should be included. Use of prescription, nonprescription, and alternative and complementary medications by study participants should be specifically documented.
Study protocols should clearly outline how adverse events will be detected, managed, and reported. Study data should be entered on case report forms designed for the study, and a quality control mechanism for ensuring the accuracy and integrity of the data should be established prior to the start of data collection. Computerized record keeping (i.e., electronic case report forms) can facilitate audits, data management, and data analysis. Adverse drug event questionnaires using extensive checklists of symptoms organized by body system have been developed for use in clinical trials (60). These are typically administered at baseline and at predetermined intervals during and after a study. To increase their utility and allow for comparisons between treatment groups, the questionnaires should be administered by a blinded investigator. Since healthy individuals who are free of illness and not taking medications can occasionally experience symptoms similar to those reported as drug side effects, adequate controls must be used in studies examining adverse drug reactions (61). Comprehensive questionnaires increase the likelihood that patient interviews are conducted in a consistent and non-superficial manner. Moreover, they minimize the risk of bias (particularly from focusing on known adverse effects) and can be useful for inter- and intrasub-ject comparisons. Of course, study participants should be encouraged to report all serious, unexpected, or bothersome symptoms, especially those that persist or require some treatment or intervention.
Toxicity criteria developed by the WHO and the National Cancer Institute (NCI) provide guidelines for objectively and systematically categorizing adverse effects according to type and severity grade. NCI's Common Toxicity Criteria (CTC) are particularly useful for studies involving antineoplastic drugs but are equally applicable to other drug categories. The CTC organizes related adverse events alphabetically according to body system or disease. For example, the "endocrine" category includes specific adverse effects such as gynecomastia and hypothyroidism. Specific criteria are detailed for grading the severity of each adverse effect. The CTC can be accessed at the NCI's Cancer Theraphy Evaluation Program web site (http://ctep.info.nih.gov/CTC3/default.htm).
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