Thrombocytopenia associated with 5-aminosalicylate prodrug, olsalazine: is the devil still there?

We present a case of a 63-year-old Chinese female who developed severe thrombocytopenia after receiving olsalazine 1.5 g daily for 3 months, and eventually culminated in hospital admission. According to a Medline search, this is the first case report of olsalazine-associated thrombocytopenia in Asia. Olsalazine, similar to other 5-aminosalicylates, can also cause thrombocytopenia. Clinicians should be aware of this potential adverse drug reaction. Future studies should focus on the trigger mechanism and possible cross-reaction between olsalazine and other aminosalicylates.