Table 1 Naranjo ADR Probability Scale

1

Are there previous conclusive reports on this reaction?

Yes (+1) No (0) Don't know (0)

+1*

2

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

Yes (+2) No (−1) Don't know (0)

+2

3

Did the adverse reaction improve when the drug was discontinued, or a specific antagonist was administered?

Yes (+1) No (0) Don't know (0)

0

4

Did the adverse reaction reappear when the drug was readministered?

Yes (+2) No (−1) Don't know (0)

0

5

Are there alternative causes (other than the drug) that could on their own have caused the reaction?

Yes (−1) No (+2) Don't know (0)

−1

6

Did the reaction reappear when a placebo was given?

Yes (−1) No (+1) Don't know (0)

0

7

Was the drug detected in the blood (or other fluids) in concentrations known to be toxic?

Yes (+1) No (0) Don't know (0)

0

8

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

Yes (+1) No (0) Don't know (0)

0

9

Did the patient have a similar reaction to the same or similar drug in any previous exposure?

Yes (+1) No (0) Don't know (0)

0

10

Was the adverse event confirmed by any objective evidence?

Yes (+1) No (0) Don't know (0)

+1

Total

+3