Hi, My 93 Yo Mother Is In The Rest Home.

Hi, my 93 yo mother is in the rest home. She has trouble sleeping. She was started on 50mg of Trazodone and then increased to 100mg then 150 mg at about 10 day intervails. She is now having al lot of agitation and nightmares. Is it possible she is getting to much? should we back off to 125mg or 100mg? This was given to her for sleep problems not depression. does the drug build up in the system??