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.

On discontinuation of the drug, serum CK concentrations returned to normal within eight days.
non-adverse drug event

No side effects or drug interactions were observed.
non-adverse drug event

We report here the case of a 36-year-old man with pre-B cell acute lymphoblastic leukemia.

non-adverse drug event