Most of the studies concluded that cognitive function was not affected by taking oxybutynin, tolterodine, or darifenacin. All of the studies were short-term which may not reflect the typical patient on these medications. Three FDA advisories have been issued which stated that there have been reports of cognitive adverse events like confusion in the post-market use of oxybutynin, tolterodine, and darifenacin. These reports do not contain enough data to determine meaningful information such as cognitive adverse event rates. It has been postulated that certain populations, such as older adults, may be less suitable candidates for oxybutynin, tolterodine, or darifenacin. Elderly patients are often taking multiple prescriptions which can increase the possibility of experiencing a drug to drug interaction and if those drugs have anticholinergic properties then the probability of cognitive impairment and other anticholinergic-associated adverse events may be higher. Given the lack of longer-term trials of oxybutynin, tolterodine, and darifenacin, it is unknown whether the longer-term use of these medications for chronic issues such as OAB negatively affects the cognitive function of patients. In addition, trials designed specifically to compare the cognitive adverse events of oxybutynin, tolterodine, and darifenacin were not identified.