Table 2.

Criteria used to evaluate causative relationships in drug-induced thrombocytopenic purpura^*

Criterion	Description
1	Therapy with the candidate drug preceded thrombocytopenia.
2	Recovery from thrombocytopenia was complete and sustained after therapy with the drug was discontinued.
2	The candidate drug was the only drug used before the onset of thrombocytopenia or other drugs were continued or re-introduced after discontinuation of therapy with the candidate drug with a sustained normal platelet count.
3	Other causes for thrombocytopenia were excluded.
4	Re-exposure to the candidate drug resulted in recurrent thrombocytopenia.
Level of Evidence
I	Definite: Criteria 1, 2, 3 and 4 are met.
II	Probable: Criteria 1, 2, and 3 are met.
III	Possible: Criterion 1 met.
IV	Unlikely: Criterion 1 not met.

^*Adapted from JN George et al (49)