Causality Assessment with Naranjo Scale

The Naranjo Scale is a structured tool for assessing the causality of adverse drug reactions. It consists of 10 questions that evaluate factors such as the timing of the reaction, dose changes, reappearance after readministration, and alternative causes. Each response generates a score to determine the likelihood that the drug caused the reaction. By systematically analyzing data like drug toxicity, previous reactions, and placebo responses, healthcare professionals can make accurate conclusions about drug causality. This tool ensures a reliable, evidence-based approach to pharmacovigilance, supporting clinical decisions and improving patient safety in adverse event assessments.

1. Are there previous conclusive reports on this reaction?

2. Did the adverse event appear after the suspected drug was administered?

3. Did the adverse event improve when the drug was discontinued or a specific antagonist was administered?

4. Did the adverse event reappear when the drug was readministered?

5. Are there alternative causes that could on their own have caused the reaction?

6. Did the reaction reappear when a placebo was given?

7. Was the drug detected in blood or other fluids in concentrations known to be toxic?

8. Was the reaction more severe when the dose was increased or less severe when the dose was decreased?

9. Did the patient have a similar reaction to the same or similar drugs in any previous exposure?

10. Was the adverse event confirmed by any objective evidence?