What Are The Side Effects Of Metoprololtartrate?

80-year old mother has recently had optic problems in one eye which have resulted in limited vision. She currently takes med for BP. She has twice been to the opthamologist: first visit resulted in a diagnosis of dry eye for which she was told to use lubricating eye drops. After no change in her vision she went back for a second visit when she was referred to a retina specialist. After thorough testing, the specialist said the eye sight was being impacted by her high BP so she needed to see her primary physician to adjust her BP meds. He did and it resulted in a slight improvement in her eyesight but not significant. She went back the primary care for a two-wk follow-up and he prescribed Metoprololtartrate to which she seems to be having adverse reactions: sleepiness, can't eat, shakey, and llethargic. We have told her to quit taking the medication and to really try to eat something and to contact her PC first thing this morning. What are the known side effects of this medication?