 [ Symptoms ] what is hypokalemia [ Disease ] hypokalemia is a medical term for low potassium levels in the blood potassium is a mineral required by the body – especially the heart – to function properly potassium levels are measured by a simple blood test low potassium levels can be caused by many things including • use of diuretics a water pill • severe or prolonged diarrhea • use of certain antibiotics such as penicillin • excessive vomiting • an eating disorder such as bulimia • hyperthyroidism very high levels of thyroid hormone caused by an overactive thyroid gland a small drop in potassium levels usually is not cause for concern and may not even cause you to experience any symptoms a larger drop in potassium levels can cause the following symptoms • constipation • fatigue • abnormal heart rhythm often experienced as palpitations • muscle spasms such as cramps in your calf muscles if you have low potassium levels your healthcare provider may prescribe a potassium supplement to fix the problem if your hypokalemia is caused by hyperthyroidism your provider may treat the thyroid problem in order to get your potassium levels back to normal