Scientific Conclusions From the MedWatch SRS

There are a number of approaches that can be used to confirm from spontaneous reports that a drug is actually causing the adverse reaction. Chapter 12 described how several FDA officials went about confirming for themselves a possible or probable causal relationship between Halcion (and Xanax) and various behavioral abnormalities, including violence. To confirm causality, some of the following factors are useful  

a disproportionately high frequency of reporting or disproportionately large number of reports in comparison to other drugs, especially in the same or similar class of medications 

a meaningful or strong enough association, as reflected in epidemiological and clinical data 

an absence of alternative explanations for the increased frequency or number of reports 

reports indicating a temporal relationship between the adverse reactions and initial doses of the drug or increased doses of the drug 

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