In vivo and in vitro testing for adverse drug reactions

The goal of providing an accurate and reliable diagnostic test for the evaluation of adverse drug reactions remains elusive. Rechallenge remains a truly conclusive method for determining the contribution of drugs to adverse effects, but there are significant disadvantages in exposing patients to drugs that may have caused serious adverse effects. Skin tests are useful for the assessment and predictive risk of serious adverse reactions for a small number of drugs, but skin tests are limited in their utility to adverse drug reactions mediated by Type 1 hypersensitivity. Skin tests must be performed with care and rigor as well. There are a number of in vitro assays that have been used for the assessment of adverse drug reactions, but many of these assays are primarily research tools and have little utility in the clinical setting. Although in vitro tests are not yet readily available for the diagnosis of adverse drug reactions, our increasing understanding of the biology of adverse drug reactions and interactions between the immune system and xenobiotics offers promise that more clinically relevant assays can be developed. At the present time, the primary diagnostic tools for the assessment of adverse drug reactions remain a careful history and physical examination and an astute, insightful physician.