Table 1 Naranjo algorithm for assessment of probability of adverse drug reaction (ADR)
Question | Yes | No | NA |
|---|---|---|---|
1. Are there previous conclusive reports on this reaction? | + 1 | 0 | 0 |
2. Did the adverse event appear after the suspected drug was administered? | + 2 | −1 | 0 |
3. Did the adverse event improve when the drug was discontinued or a specific antagonist was administered? | +1 | 0 | 0 |
4. Did the adverse event reappear when the drug was readministered? | +2 | −1 | 0 |
5. Are there alternative causes that could on their own have caused the reaction? | −1 | +2 | 0 |
6. Did the reaction reappear when a placebo was given? | −1 | +1 | 0 |
7. Was the drug detected in blood or other fluids in concentrations known to be to | +1 | 0 | 0 |
8. Was the reaction more severe when the dose was increased or less severe when the dose was decreased? | +1 | 0 | 0 |
9. Did the patient have a similar reaction to the same or similar drugs in any previous exposure? | +1 | 0 | 0 |
10. Was the adverse event confirmed by any objective evidence? | +1 | 0 | 0 |
Total score | Interpretation of scores | ||
Total score ≥ 9 | Definite | ||
Total score 5–8 | Probable | ||
Total score 1–4 | Possible | ||
Total score ≤ 0 | Doubtful | ||