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.

Example Input: Laboratory investigations confirmed a metabolic acidosis (pH 7.15) and hyperchloremia.
Example Output: non-adverse drug event

Example Input: Isoniazid inhibits the conversion of tryptophan to niacin and may induce pellagra, particularly in poorly nourished patients.
Example Output: adverse drug event

Example Input: Previously reported cases of persistent proximal right umbilical vein have shown a variety of other malformations but a single umbilical artery has been the most consistent.
Example Output:
non-adverse drug event