Hi
Risperidone is mainly used to treat Schizophrenia and Bipolar disorder, and sometimes for those that have autism. It can be used for episodes of extreme agitation or violent outbursts in Dementia sufferers, although a lot of GP's are usually reluctant to prescribe. If it is prescribed for Dementia, it's usually for short periods of time, I think around 4-6 weeks, and it should be reduced down, not stopped straight away. It can have huge effects. And some of the side effects are not nice either ( insomnia, dizziness, respiratory infections, nausea, headaches, joint ain to name a few ) There is a HIGH risk of stroke / mini stroke, and also Dysphagia ( swallowing )
A lot of the elderly I know that had the medication, initially, it made them sleepy, and after a while, it didn't have the desired effect ( reducing the agitation ) but made them more susceptible to falls and the above side effects.
My advice would be to see whoever prescribed and discus an alternative, especially as your Mum is having falls and is still agitated. UTI's and other infections play havoc with Dementia, so that needs to be gotten under control too, maybe Mum won't be AS agitated. I'm sorry if it's not much help or if I've told you anything you don't already know, but if there's anything more I can think of, i'll add it.
Take care now x