Hello, Vancomycin as you know is a commonly prescribed antibiotic, usually given IV for serious infections. Some of the more common side effects that line up with your concerns include tiredness or weakness, however much less common side effects but still are reported with Vancomycin are dizziness, lightheadedness and tremulousness (shakiness). I would ask you you have your BP checked in both a sitting and a standing position which may help provide a better idea for your doctor as to what exactly is causing these symptoms. I do think if these worsen you should be evaluated by the ER and certainly let your physician know of the side effects as the dizziness and shakiness are not common occurrences. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. David Girardi, Internal Medicine Specialist