Sundown syndrome: is it reflected in the use of PRN medications for nursing home residents?

Sundown syndrome describes the increase in agitation and delirium in elderly patients with dementia that occurs in the evening after sunset. In a nursing home, data were gathered over a year-long period to test the hypothesis that the administration of PRN (pro re nata, given as needed) medications for agitation in Alzheimer's patients would reflect sundown syndrome. More PRNs were administered in the early morning and mid-afternoon hours than at other times of the day. These outcomes suggest there is a relationship of PRN use for agitation, in institutionalized Alzheimer's patients, to environmental variables other than sunset.