Low Potassium

Potassium is a mineral needed in small amounts for cell, nerve, and muscle function. Under normal circumstances, your body will automatically control potassium levels in your blood. Low potassium, also known as hypokalemia, can have many causes that result in mild to severe symptoms.

Low potassium levels are most frequently caused by certain medications or medical conditions, including gastrointestinal symptoms such as diarrhea and vomiting. While low potassium usually is not dangerous, severely low levels can cause serious complications that can affect your nervous and digestive systems and your heart.

This article discusses the symptoms, possible causes, diagnostic tests, and treatment strategies of low potassium. It also covers when to seek medical treatment for your symptoms.

Symptoms of Low Potassium

In mild cases of low potassium, you may not have any symptoms. In more severe cases, symptoms of low potassium include:

• Leg cramps
• Muscle weakness
• Fatigue
• Constipation
• Abnormal heart rhythm (cardiac arrhythmia)
• Kidney problems

Causes of Low Potassium

While low potassium can result from not getting enough potassium in your diet, it is more likely caused by conditions in which your body excretes too much potassium, either from the gastrointestinal tract or your kidneys.

Low potassium can also occur due to transcellular shift, in which your cells take too much potassium from the bloodstream.

Some of the most common causes of low potassium are:

• Chronic diarrhea (including from laxative use)
• Frequent vomiting
• Osmotic diuresis (increased urination due to certain substances found in fluid filtered by the kidneys)
• Mineralocorticoid excess (high blood pressure caused by one mutated gene from each parent)
• Cushing’s syndrome (high exposure to cortisol)
• Hyperaldosteronism (excess aldosterone hormone released by the adrenal glands)
• Bartter syndrome (kidneys are unable to reabsorb certain compounds and electrolytes)
• Insulin administration
• Thyrotoxicosis (excess thyroid hormones in the body)
• Renal tubular acidosis (kidneys are unable to get rid of enough acid, retain enough base, or both)

What Medications Can Cause Low Potassium?

Low potassium levels are often associated with the use of certain medications. Diuretics, also known as water pills, are one of the most common classes of medications that can lead to low potassium. Diuretics treat many conditions, including high blood pressure, congestive heart failure, and pulmonary edema.

Diuretics help remove excess fluid from the body and increase urine flow. Potassium is also released through urine, so diuretics may sometimes cause too much potassium to leave the body.

Other medications that can cause low potassium are:

• Antimicrobials including ampicillin, penicillin, aminoglycosides such as gentamicin
• Beta2-receptor agonists, including ProAir HFA (albuterol), Akovaz, (ephedrine), and EpiPen(epinephrine)
• Diuretics including Diamox (acetazolamide), Zaroxolyn (metolazone), and thiazides such as Zaroxolyn (metolazone),
• Insulin
• Mineralocorticoids and glucocorticoids including hydrocortisone, fudrocortisone, and prednisone
• Laxatives including Kayexalate (sodium polystyrene sulfonate), Arlex (sorbitol), and phenolphthalein
• Xanthines including theophylline and caffeine

How to Treat Low Potassium

If you are experiencing symptoms of low potassium, talk to your healthcare provider. Low potassium should not be self-treated and usually requires a medical test to determine severity. Treatments for low potassium aim to increase potassium levels and resolve the underlying causes.

Oral Potassium Supplements

In mild cases, low potassium may be treated with oral potassium pills provided by your doctor. These may be in the form of potassium chloride (e.g., Klor-Con, K-tab), potassium phosphate (e.g., Neutra-Phos, K-Phos Neutral), or potassium carbonate (e.g., Effer-K, K-Bicarb). Your healthcare provider will determine which oral potassium supplement is appropriate for you. 

Intravenous Potassium

In severe cases, you may need to receive intravenous (IV) potassium in the hospital. This treatment raises levels much quicker than oral potassium supplementation but also carries a risk of inducing hyperkalemia, a condition in which potassium levels get too high.

Hyperkalemia can cause serious symptoms as well. Patients receiving IV potassium need to be closely monitored by their healthcare team.

Dietary Potassium

Eating more potassium-rich foods can also help treat and prevent low potassium levels, though in many cases, you may not get enough from diet alone. Foods that are high in potassium include:

• Lima beans
• Swiss chard
• Potatoes
• Acorn squash
• Spinach
• Kiwi
• Orange juice
• Bananas
• Yogurt
• Salmon

Complications and Risk Factors Associated With Low Potassium

Though mild low potassium is not dangerous and can easily be treated with oral potassium supplementation, severely low potassium levels can cause serious complications. In severe cases of low potassium, life-threatening heart failure, paralysis, and respiratory failure can occur.

If you have a heart condition such as cardiac ischemia, heart failure, or left ventricular hypertrophy, low potassium levels are more likely to cause further cardiac problems. If this is the case, contact your doctor immediately if you are experiencing any symptoms.

Are There Tests to Diagnose the Cause of Low Potassium?

Low potassium is diagnosed through a basic biochemical lab panel, which tests potassium levels in your blood and other compounds such as sodium, glucose, chloride, bicarbonate, blood urea nitrogen (BUN), and creatinine. If the reason for your low potassium is unclear, additional tests may be needed to determine the underlying cause.

To explain the cause of your low potassium, your healthcare provider may order the following tests:

• Urine electrolyte test: This test will measure potassium and chloride levels in your urine to help determine if the cause is related to your kidneys.
• Arterial blood gas (ABG): This test can determine if you have metabolic acidosis or alkalosis, conditions where your body’s acid-base balance has been thrown off.
• Electrocardiogram (ECG): This test will check for abnormal heart rhythms caused by low potassium.

When to See a Healthcare Provider

Consult a healthcare provider to help assess your symptoms and determine if you have low potassium levels if you are experiencing any of the following symptoms:

• Heart arrhythmia (irregular heartbeat)
• Muscle cramping
• Paralysis 
• Respiratory problems

Low potassium can be especially dangerous if you have an underlying heart condition. Seek treatment right away if you think your potassium levels may be low.

Summary

Low potassium (hypokalemia) symptoms depend on the severity of your case. Mild low potassium may show no symptoms, while more severe low potassium symptoms can include serious heart and neuromuscular complications. Many conditions and medications may cause low potassium, usually due to the body excreting too much potassium from your gastrointestinal tract or kidneys or causing a transcellular shift.

If you are experiencing symptoms of low potassium, seek medical care so a provider can test your blood levels. If your potassium levels are low, potassium supplementation with oral pills or intravenous infusion is the most common treatment. A diet that includes potassium-rich foods can help improve your potassium levels, but food alone is not usually sufficient to treat hypokalemia.

A Word From Verywell

Having low potassium levels is a common health concern easily treated in most cases. However, it should still be taken seriously to prevent further problems, especially if you have an underlying heart condition. Once your healthcare provider diagnoses your low potassium, they will identify the best treatment strategy for you to help relieve symptoms and improve your potassium levels.