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Table 2 Naranjo Adverse Drug Reaction Probability Scale scoring system

From: Levothyroxine-induced liver injury followed by complete recovery upon cessation of the drug: a case report

Question Yes No Do not know Score
Are there previous conclusive reports on this reaction? +1 0 0 +1
Did the adverse event appear after the suspected drug was administered? +2 −1 0 +2
Did the adverse reaction improve when the drug was discontinued or a specific antagonist was administered? +1 0 0 +1
Did the adverse event reappear when the drug was readministered? +2 −1 0 +2
Are there alternative causes (other than the drug) that could on their own have caused the reaction? −1 +2 0 +2
Did the reaction reappear when a placebo was given? −1 +1 0 0
Was the drug detected in blood (or other fluids) in concentrations known to be toxic? +1 0 0 0
Was the reaction more severe when the dose was increased or less severe when the dose was decreased? +1 0 0 0
Did the patient have a similar reaction to the same or similar drugs in any previous exposure? +1 0 0 0
Was the adverse event confirmed by any objective evidence? +1 0 0 0
Total score     8