Low potassium has many causes. The most common cause is potassium loss in urine due to prescription medicines that increase urination. These types of medicines, also known as water pills or diuretics, typically are prescribed to treat high blood pressure or heart disease. But these medicines may be prescribed to treat swelling of any type.

Vomiting, diarrhea or both also can result in potassium loss. Sometimes, low potassium is caused by not getting enough potassium in your diet.

Causes of potassium loss include:

1. Alcohol use
2. Chronic kidney disease
3. Diabetic ketoacidosis (in which the body has high levels of blood acids called ketones)
4. Diarrhea
5. Diuretics medicines, also known as water pills
6. Excessive laxative use
7. Excessive sweating
8. Folic acid deficiency
9. Primary aldosteronism
10. Some antibiotic use
11. Vomiting