What term is defined as reported information on a possible causal relationship between an adverse event and a drug?

The term that is defined as reported information on a possible causal relationship between an adverse event and a drug is referred to as a "signal." In pharmacovigilance, a signal indicates that there might be a new or increased risk associated with the use of a specific medication, based on adverse event data. This could come from various sources, such as clinical trials, post-marketing surveillance, or spontaneous reports from healthcare providers and patients.

Once a signal is detected, it prompts further investigation to determine whether there is a legitimate cause-and-effect relationship. This process is important because it helps ensure drug safety and can lead to regulatory actions, such as labeling changes, risk communication efforts, or even further research to better understand the adverse event in question.

Other terms like "alert," "index," and "indicator" do not have the same specific meaning within the context of pharmacovigilance, as they typically imply different actions or types of data. An alert may indicate a warning based on various information but does not refer specifically to the preliminary data suggesting a causal link.