Adverse drug reactions are appreciably harmful or unpleasant reactions resulting from an intervention related to the use of medical products, which predicts hazard from future administration and warrants prevention or specific treatment, or alteration of the dosage regimen, or withdrawal of the product. Given medical case reports extracted from MEDLINE, the task is to classify whether the case report mentions the presence of any adverse drug reaction. Classify your answers into non-adverse drug event and adverse drug event.
Q: Contrary to previous recommendations, our experience cautions against the further use of high-dose cytarabine in patients who develop PPE, and is a timely reminder of the potential toxicity of this agent, which is now increasingly being used as first-line treatment in the management of haematologic malignancies.
A: 
adverse drug event