Adverse drug reactions (ADRs) are when people have bad effects from taking medicine. These reactions are important because they help doctors and scientists understand how to classify drugs based on safety.

1. Impact on Categories:

   • Sometimes, ADRs can make us change a drug’s label from “low-risk” to “high-risk.” This means we need to be more careful with that medicine.

2. Statistics:

   • About 6.7% of people who go to the hospital do so because of ADRs.
   • In the U.S., around 1.3 million people visit emergency rooms each year because of problems related to medications.

3. Mechanisms of Action:

   • Learning about ADRs helps us understand how drugs work. This information is important for creating safer medicines and deciding how to classify them.