13 Medications That Can Interfere With Your Calcium Levels

While calcium is most commonly known for keeping your bones and teeth strong, it actually has many roles in the body. These include helping your muscles, blood vessels, and nervous system function well. 

But, what happens when blood calcium becomes too low or too high? Abnormal calcium levels like hypocalcemia (low calcium in blood) or hypercalcemia (high calcium in blood) may lead to serious health problems, like seizures and abnormal heart rhythm. 

Certain medications you might be taking can affect your calcium levels. Below, we’ll talk about a total of 13 medications: Eight that can lead to low calcium and five that can cause high calcium in the blood. We’ll also cover symptoms to look out for in both cases.

Medications that can cause low calcium levels

These medications can cause low calcium levels:

1. Bisphosphonates: Bisphosphonates are medications for osteoporosis (weak and brittle bones) that prevent bones from losing calcium. As a result, less calcium ends up in the bloodstream. Your calcium levels can become low with tablets like ibandronate (Boniva) and alendronate (Fosamax). But it’s more likely to happen with high doses of strong bisphosphonates, like zoledronic acid (Reclast), a medication given intravenously (IV).

2. Prolia: Denosumab (Prolia) is an injection given once every 6 months to treat osteoporosis. Like bisphosphonates, Prolia prevents bones from releasing calcium into the blood and can cause low calcium levels.

3. Sensipar: Cinacalcet (Sensipar) is prescribed to people with chronic kidney disease (CKD) to lower parathyroid hormone (PTH) levels. PTH is a hormone that tells the bones to release calcium into the bloodstream. So less of this may lead to low calcium in the blood.

4. Phenytoin: Phenytoin (Dilantin) is an anti-seizure medication that, as a side effect, lowers vitamin D levels. In turn, this can affect how much calcium you absorb from food and lead to low calcium levels. This is especially the case with long-term use.

5. Cisplatin: Cisplatin is a chemotherapy medication used to treat many types of cancer including bladder, ovarian, and esophageal cancer. It causes low magnesium, which leads to low PTH and low calcium.

6. Diuretics: Loop diuretics are used for high blood pressure, heart failure, and leg swelling. Examples of loop water pills include furosemide and torsemide. Loop diuretics affect the way the kidney handles calcium, which can lead to loss of calcium through the urine.

7. Proton pump inhibitors (PPIs): PPIs are used for gastroesophageal reflux disease (GERD). Some common PPIs include omeprazole (Prilosec) and esomeprazole (Nexium). PPIs can lead to lower calcium absorption and low blood calcium levels, but this is usually rare.

8. Aminoglycosides: Aminoglycoside antibiotics are used for bacterial infections. Examples of aminoglycosides include tobramycin (Tobi) and gentamicin (Gentak). Aminoglycosides might also cause hypocalcemia by affecting the way the kidneys handle calcium.  

Low calcium symptoms

What happens when your blood calcium is too low? Not everyone experiences symptoms, especially if your calcium is only a little bit low. But if you do, some low calcium symptoms may include:

• Mood changes

• Muscle spasms and cramps

• Numbness or tingling sensation

• Seizures

• Abnormal heart rhythm

Medications that can cause high calcium in the blood

Here are five common medications linked to high calcium levels:

1. Lithium: Lithium is a medication for bipolar disorder that can raise parathyroid hormone (PTH) levels in the blood, and as a result, calcium levels.

2. Diuretics: Thiazide diuretics like hydrochlorothiazide (Microzide) and chlorthalidone are used to treat high blood pressure. But these medications can also raise calcium levels by preventing calcium from being released into the urine.

3. Calcium and Vitamin D supplements: People take calcium and vitamin D supplements for many different reasons. Some people also take these medications for osteoporosis and low vitamin D. Some people take calcium carbonate (TUMS) to help with an upset stomach. No matter the reason, taking too much vitamin D or calcium may result in high calcium levels. 

4. Forteo: Teriparatide (Forteo) is an injectable medication that’s used to treat osteoporosis. Forteo is a human-made version of PTH that works similarly to PTH and can raise calcium levels.

5. Theophylline: Theophylline isn’t routinely used anymore. But in the past, it was commonly used for lung conditions, such as asthma. At high doses, this medication is linked to high calcium levels. But this is rare, and it’s unclear how this exactly happens.

Symptoms of high calcium in the blood 

How do you know if you have high calcium levels in your blood? The most common symptoms of having too much calcium may include:

• Confusion or mood changes 

• Fatigue

• Muscle weakness

• Increased thirst

• Frequent urination (peeing)

• Kidney stones

• Constipation

• Nausea

• Lack of appetite

If your blood calcium spikes suddenly and too dramatically, it could cause dangerous symptoms like extreme confusion or a low heart rate that may cause you to lose consciousness.

What to do if your calcium levels are too low or too high

Normal calcium levels in your blood will typically range from 8.8 to 10.4 milligrams (mg) per deciliter (dL).

If you suspect that you have a calcium imbalance, talk with a healthcare provider. They can advise you on next steps, such as getting a calcium blood test. 

If you do have abnormal calcium levels, your healthcare provider will help you come up with a treatment plan. Many times, hydration can help lower calcium levels, while calcium supplements can help raise your calcium levels. But it’s best to work with a healthcare provider to figure out the next best step.

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Written by:

Ross Phan, PharmD, BCACP, BCGP, BCPS

Ross Phan is a board-certified clinical pharmacist. She has roughly two decades of healthcare experience — with most of her experience being pharmacy related.

Edited by:

Samvida Patel, MNSP, INHC

Samvida Patel, MNSP, INHC, is a health editor at GoodRx. She is a nutritionist and integrative nutrition health coach with over 8 years of experience in health communications.

Reviewed by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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