welcome to hcm, I really appreciate your concern, potassium chlorile does have side effects like nausea, vomiting,muscle weakness ,arrythmias,diarrhea abdominal discomfort among other symptoms. most of these are due to the elevated levels of serum potassium after usage of kcl. there will not be any withdrawal effects of kcl is stopped abruptly unless the potassium levels drop leading to hypokalemia. i would suggest an ECG along with serum electrolytes to know any rythm abnormality of the heart and the levels of potassium in blood. based on the results of these hyperkalemia if present can be managed accordingly by your physician. Please let me know if you have any further questions. Thanks. regards.