What are adverse drug reactions (ADRs)?

Adverse drug reactions (ADRs) are defined as harmful or unintended responses that occur when a medication is administered at normal therapeutic doses. This means that even when a drug is used correctly and in the right amount, it can still cause negative side effects or reactions in patients. Identifying and understanding ADRs is critical in clinical practice as it helps ensure patient safety and optimize therapeutic outcomes.

While desired effects of medications occur at therapeutic doses, they do not qualify as ADRs. Drug-drug interactions can lead to adverse reactions, but ADRs themselves are not limited to these interactions; they can arise from a single medication. Allergic responses can be a form of ADRs but are not restricted to specific drug classes, as various medications can provoke allergies in different individuals, making it a broader category. Hence, the definition that captures the essence of ADRs is the harmful reactions that arise at normal doses of medication.