Adverse reaction reports describe suspected side effects. A report does not mean the drug caused the event — co-medications, underlying disease and coincidence all contribute.
Who is the marketing authorisation holder for Oxybutynin Cl in United States?
Sehit Prof. Dr. Ilhan Varank Sancaktepe Training and Research Hospital is the originator. The local marketing authorisation holder may differ — check the official source linked above.