Table 5.

Naranjo [8] Causality Scale for Adverse Drug Reactions.

Question/Scoring-Yes/No/Do not know or unavailable		Case 1	Case 2
1	Are there previous conclusive reports on this reaction? 1/0/0	0	0
2	Did the adverse event appear after the suspected drug was given? 2/−1/0	2	2
3	Did the adverse reaction improve when the drug was discontinued or a specific antagonist was given? 1/0/0	1	1
4	Did the adverse reaction appear when the drug was readministered? 2/−1/0	0	0
5	Are there alternative causes that could have caused the reaction? −1/2/0	−1	−1
6	Did the reaction reappear when a placebo was given? −1/1/0	0	0
7	Was the drug detected in any body fluid in toxic concentrations? 1/0/0	0	0
8	Was the reaction more severe when the dose was increased/ increasing, or less severe when the dose was decreased? 1/0/0	1	1
9	Did the patient have a similar reaction to the same or similar drugs in any previous exposure? 1/0/0	0	0
	Total score	3	3

Scoring: >9 : definite adverse drug reaction (ADR).

5–8 : probable ADR.

1–4 : possible ADR.

0 : doubtful ADR.