What Is Calcium Gluconate?

Emergency Treatment for Both Low Calcium and High Potassium

Calcium Gluconate tablets and capsules

Verywell / Anastasia Tretiak

Calcium is a mineral element, and the most abundant mineral, found in the body. Along with potassium and magnesium, calcium is essential for muscle contraction and nerve conduction. It is a foundation for bone structure and occurs naturally in several forms and in many foods. Calcium gluconate is a version of calcium found in gluconic acid, a carboxylic acid found in plants—especially fruits—and honey.

Calcium is used medically in many forms, including calcium chloride, calcium formate, calcium citrate, or calcium gluconate. Intravenous calcium gluconate and calcium chloride are commonly used in emergency medicine. Oral calcium gluconate can also be used as a calcium supplement but is probably not be the best option for use as a long-term solution.

What Is Calcium Gluconate Used For?

Calcium gluconate is most commonly used in emergency situations to treat several conditions. It is not well-suited to return low blood calcium levels to normal. Instead, calcium gluconate is used to mitigate the signs and symptoms of low calcium levels or high potassium levels.

Calcium gluconate is sold as a calcium supplement, but other calcium preparations are better for maintaining healthy calcium levels in the body.

Hypocalcemia (Low Calcium Levels)

Calcium deficiency leads to various medical diagnoses. Signs and symptoms of hypocalcemia depend on whether it is acute or chronic onset (came on quickly or over a long time period).

Acute hypocalcemia can develop muscle spasms in the hands and feet, and large muscle or abdominal cramps. Low calcium levels can also lead to irritable reflexes and cardiac dysrhythmias.

Hypocalcemic tetany: Muscle spasms of the face, or of the hands and feet (known as carpal-pedal spasms). Tetany (spasms in the hands, jaw, and feet) can have multiple causes. Hypocalcemic tetany is related to low calcium levels in the blood and can be a sign of acute pancreatitis.

Vitamin D deficiency: A lack of vitamin D in the diet, renal failure or liver failure, and too little exposure to sunlight can all lead to vitamin D deficiency. Vitamin D deficiency and hypocalcemia are interrelated and often are treated together.


A lack of parathyroid hormone (PTH) in the body is known as hypoparathyroidism. Hypoparathyroidism can lead to hypocalcemia, which can also be the first indication of hypoparathyroidism.


Muscle contraction and nerve conduction rely on a proper balance of potassium and calcium in the blood and body tissues. Acute (sudden) hyperkalemia (high levels of potassium in the blood) has essentially the same effect on muscle and nerve physiology as hypocalcemia. The use of intravenous calcium gluconate can help to balance the effects of the increased potassium.

Hydrofluoric Acid Burn

Chemical burns from hydrofluoric acid have reacted well to treatment with calcium gluconate. Use of a gel with calcium gluconate can be applied topically to a hydrofluoric acid burn.

Healthcare providers may also use an infusion of calcium gluconate into the arteries to treat hydrofluoric acid burns of the distal (far end) parts of the arms and legs.

Calcium Channel Blocker Overdose

Blood pressure medications that are known as calcium channel blockers lower blood pressure by slowing down the ability of the calcium to react across muscle cell membranes. It reduces the effectiveness of heart muscle tissue and lowers the blood pressure overall.

Experts recommend intravenous calcium via either calcium gluconate or calcium chloride for overdoses of calcium channel blockers.

Possible Side Effects

Potential adverse effects of calcium gluconate depend on the route of administration. Rapid intravenous (IV) administration may lead to more severe immediate reactions than long-term oral dosing. Oral calcium is more likely to lead to adverse gastrointestinal effects.

Many of the side effects of calcium gluconate are similar to signs of elevated levels of calcium in the bloodstream (hypercalcemia).

Some patients report a chalky taste in the mouth after IV administration.

Allergic Reactions

Typical signs and symptoms of anaphylaxis include hives, itching, wheezing, shortness of breath, difficulty swallowing, confusion, low blood pressure, and loss of consciousness.

Calcium Gluconate capsules
Verywell / Anastasia Tretiak

Dosage and Preparation

Calcium gluconate can be given either intravenously, orally, or topically. It cannot be given intramuscularly or subcutaneously (under the skin).

Intravenous Calcium Gluconate

Most emergency doses of calcium gluconate are given intravenously (IV), either as a bolus (single dose of medication given at one time and pushed directly into the IV line) or as a drip infusion given over time.

IV concentrations are usually 100 milligrams per milliliter (mg/ml) and commercially prepared. Other IV preparations for drip infusion or pediatric administration can be diluted with normal saline or 5% dextrose solutions.

IV calcium gluconate is typically administered with an initial loading dose (bolus) of 1 to 2 grams. Additional doses of 1 to 2 grams IV bolus can be given every six hours. Continuous IV drip infusion can be administered between 5 to 20 milligrams per kilograms (mg/kg) per hour.

The emergency physician will determine dosages for calcium gluconate based on the patient's signs and symptoms as well as through laboratory blood testing.

Oral Calcium Gluconate

Oral concentration tablets are available in 50 mg, 500 mg, and 650 mg, while oral concentration capsules are available in 500 mg.

Calcium gluconate is not considered ideal for use as a dietary supplement. Absorption of elemental calcium (the actual mineral) is not as effective with calcium gluconate as it is with other types of calcium supplements.

Your healthcare provider may prescribe calcium gluconate to help control calcium levels depending on your condition.

What to Look For

Calcium gluconate is available over the counter as a dietary supplement, but there are better options to choose from. This is a medication with clear clinical significance to treat certain medical conditions, but it is not that useful as a daily calcium supplement for things like bone health or to treat osteoporosis.

Starting with good dietary choices is always the foundation for maintaining the right balance of electrolytes. You will also absorb elemental electrolytes better by eating foods rich in minerals than by taking supplements. Everyone knows that milk and dairy products are high in calcium, but so are seeds, dark leafy greens like collards and kale, almonds, soybeans, and sardines.

Even people who eat a diet that includes calcium-rich foods may benefit from a supplement, but there is such a thing as too much calcium. Plus, the complicated interplay between calcium, potassium, magnesium, and vitamin D make this a supplement that should be used with the advice of your healthcare provider.

A Word From Verywell

The use of mineral and vitamin supplements can be very beneficial but are not completely without risk. It's well known that many people, especially postmenopausal women and those with osteoporosis, can use the extra calcium that supplements provide. It might need to come with magnesium or vitamin D to make the best use of it and that level of complexity really needs a healthcare provider to help you navigate it.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Rod Brouhard, EMT-P
Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients.