One of the dangers is a rapid or irregular heartbeat, nervousness, and you can sometimes get a little "out of it" It is a wonderful mineral, but one you need to take in moderation. I would also ask a pharmacist about this and also a health food store.
Heart problems would be a major problem associated with this seeing as how your heart is partially controlled by potassium.
From another website: "Abnormal potassium levels may cause symptoms such as muscle cramps or weakness, nausea, diarrhea, frequent urination, dehydration, low blood pressure, confusion, irritability, paralysis, and changes in heart rhythm." It does not specify which side effects are from potassium being too high and which are associated with it being too low, but you could certainly google "potassium too high" and get some good information.