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.
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Question: PDT was performed twice, but after the second cycle, patient developed choroidal ischemia and the visual outcomes were poor.

Answer: non-adverse drug event


Question: CASE REPORT: A 64-year-old man was evaluated for chronic low-back pain after multiple spine surgeries.

Answer: non-adverse drug event


Question: Erythema multiforme bullosum due to rifampicin.

Answer:
adverse drug event