The normal value of potassium is 3.5-5.5 mmol/L. If the value is lower than 3.5 mmol/L, the patient is in a state of hypokalemia and can take oral or intravenous potassium supplements. If the patient does not have sufficient urine output, potassium supplementation is not indicated. When the skeletal muscle is twitching or hypokalemic, it is important to give adequate amounts of potassium. Hypokalemia can easily cause cardiac arrhythmias, which should be prevented with appropriate sodium supplementation to counteract the symptoms of hypokalemia.