Prolia (denosumab) is a prescription drug used to treat weakened bones or help prevent bone loss. Prolia can cause side effects that range from mild to serious. Examples include joint pain and dental or jaw-related side effects.

Prolia is an injection prescribed for certain adults with osteoporosis, which is a condition that causes your bones to weaken. Prolia is also used to help prevent bone fractures in people with breast or prostate cancer who are taking certain medications.

The active ingredient in Prolia is denosumab. (An active ingredient is what makes a drug work.) This is a biologic medication, which means it’s made from parts of living organisms.

For more information about Prolia, including details about its uses, see this in-depth article on the drug.

Like other drugs, Prolia injections can cause mild or serious side effects. Keep reading to learn more.

Prolia has a boxed warning. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Side effects explained” section below.

These are just a few of the more common side effects reported by people who took Prolia in studies. These side effects can vary depending on which condition the drug is being used to treat or help prevent.

More common side effects in females* using Prolia for osteoporosis after menopause include:

More common side effects in males* using Prolia for osteoporosis include:

More common side effects in people using Prolia for osteoporosis caused by taking glucocorticoid drugs include:

More common side effects in people receiving certain treatments for breast or prostate cancer while also using Prolia to help prevent bone loss include:

  • joint pain†
  • back pain
  • pain in the arms and legs
  • pain in the muscles

* In this article, we use the terms “male” and “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.
† To learn more about this side effect, see “Side effects explained” below.

Mild side effects in females* using Prolia for osteoporosis after menopause include:

Mild side effects in males* using Prolia for osteoporosis include:

Mild side effects in people using Prolia for osteoporosis caused by taking glucocorticoid drugs include:

Mild side effects in people receiving certain treatments for breast or prostate cancer while also using Prolia to help prevent bone loss include:

  • joint pain†
  • back pain
  • pain in the arms and legs
  • pain in the muscles

* In this article, we use the terms “male” and “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.
† To learn more about this side effect, see “Side effects explained” below.

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop using Prolia unless your doctor tells you to.

Prolia may cause mild side effects other than the ones listed above. See the Prolia prescribing information to learn more.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Prolia, visit MedWatch.

Serious side effects from Prolia aren’t common, but they may occur.

Serious side effects that have been reported with Prolia include:

* To learn more about this side effect, see “Side effects explained” below.

If you develop serious side effects while using Prolia, call your doctor right away. If the side effects seem life threatening or if you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Most side effects from Prolia are mild and go away on their own after a few days.

Although rare, Prolia may cause some long-term side effects. These include:

  • High cholesterol: If you develop this side effect, you may need medication to treat it.
  • Low blood calcium level: This side effect usually won’t go away on its own, but it can be treated with medication.
  • Unusual fractures in the thigh bone: Bone breaks can take months to heal.*
  • Dental and jaw-related side effects: These side effects may take time to heal.*

Before you start treatment with Prolia, your doctor and pharmacist will discuss potential side effects of Prolia. They should mention long-term side effects as well as short-term side effects.

* To learn more about this side effect, see “Side effects explained” below.

Learn more about some of the side effects Prolia may cause.

Risk of severely low blood calcium levels

Prolia has a boxed warning. A boxed warning is the most serious warning from the FDA. A boxed warning alerts doctors and patients about drug effects that may be dangerous.

Prolia can cause low blood calcium levels in people with advanced chronic kidney disease. This condition can be severe and, in some cases, life threatening. It was not a common side effect reported in studies of Prolia. Low blood calcium levels may cause symptoms such as:

Factors that can increase the risk of severely low blood calcium levels when using this drug include:

  • chronic kidney disease
  • certain mineral and bone conditions

What might help

If you have low blood calcium levels before starting Prolia, talk with your doctor. They’ll likely recommend that you supplement your diet with calcium, vitamin D, or both. This is meant to help increase the amount of calcium in your blood.

If you have this condition during treatment with Prolia, your doctor will likely recommend the same treatment to help increase your blood calcium levels. They’ll continue to monitor you for signs of this condition while you receive the drug.

Dental and jaw-related side effects

Although rare, it’s possible to have dental and jaw-related side effects from using Prolia.

Symptoms of dental and jaw-related side effects can include:

One potential complication is jaw necrosis (death of jawbone tissue). This may cause teeth to become loose and need to be removed. According to the American Dental Association, the risk of jaw necrosis increases if denosumab, the active drug in Prolia, is used for more than 2 years.

What might help

Before you begin treatment with Prolia, your doctor should examine your mouth. They may recommend that you see a dentist before starting Prolia.

You should practice good oral hygiene while using Prolia, including brushing and flossing your teeth. This can help prevent dental and jaw-related side effects that Prolia might cause.

If you notice any symptoms of dental or jaw-related side effects while using Prolia, contact your doctor or dentist right away. You should also contact your doctor or dentist if you experience pain or slow healing following dental surgery.

Before you have any dental procedure, be sure to tell your dentist that you’re using Prolia.

Joint pain

Pain, including joint pain, is a possible side effect of Prolia. Joint pain was mild in studies. But after these studies were done, some people have reported severe joint pain while using Prolia.

What might help

If you have any joint pain while using Prolia, talk with your doctor.

But if your pain is severe, it’s important to contact your doctor right away. They may want to check you for fractures. Fractures can cause joint pain, even when the fracture isn’t in the joint itself.

Your doctor may recommend treatment for your pain, depending on the severity. They may also recommend that you stop using Prolia and try a different medication for your condition.

Risk of bone fractures after skipping or stopping treatment

Skipping a dose of Prolia or stopping use of the drug increases the risk of bone fractures. This includes an increased risk of multiple bone fractures in the spine.

When stopping Prolia, bone turnover increases to above-usual values 9 months after the last dose. “Bone turnover” refers to how quickly your bones replace old bone tissue with new bone tissue. Bone turnover takes about 24 months after the last dose of Prolia to return to a typical rate.

What might help

If you use Prolia, you’ll likely get an injection once every 6 months. To avoid an increased risk of bone fractures, it’s important that you don’t miss a dose. If you do miss an injection, call your doctor or pharmacy to reschedule as soon as possible. (Prolia injections are only given by a healthcare professional.)

If you and your doctor agree that it’s best for you to stop using Prolia, ask your doctor about other medications you could take. They may recommend another treatment for your condition to help your bones stay strong and healthy.

Unusual fractures in the thigh bone

While rare, Prolia has caused unusual fractures in the thigh bone. Symptoms of a thigh bone fracture are new or unusual feelings of pain in the hip, thigh, or groin.

What might help

While using Prolia, contact your doctor right away if you notice new or unusual pain in your hip, thigh, or groin.

Sometimes, this pain occurs before a fracture occurs. You may notice a dull, aching pain weeks or even months before a fracture happens.

If you have new or unusual pain in your hip, thigh, or groin, your doctor will likely have you temporarily stop Prolia. They’ll weigh your risks against the possible benefits of continuing the drug and discuss your treatment options with you.

Allergic reaction

Like most drugs, Prolia can cause an allergic reaction in some people.

Symptoms can be mild or serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms. Examples include:

  • an antihistamine that you take by mouth, such as Benadryl (diphenhydramine)
  • a product you apply to your skin, such as hydrocortisone cream

If your doctor confirms you had a mild allergic reaction to Prolia, they’ll decide if you should continue using it.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you had a serious allergic reaction to Prolia, they may have you switch to a different treatment.

Keeping track of side effects

During your Prolia treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things like:

  • what dose of drug you were taking when you had the side effect
  • how soon after starting that dose you had the side effect
  • what your symptoms were from the side effect
  • how it affected your daily activities
  • what other medications you were also taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help your doctor learn more about how the drug affects you. And your doctor can use this information to adjust your treatment plan if needed.

Get answers to some frequently asked questions about Prolia’s side effects.

How long after beginning Prolia injection do side effects start?

It depends. Some side effects can start soon after your first dose of Prolia. But other side effects may take longer to start, and some may not start until after you stop receiving Prolia injections.

For example, the risk of bone fractures is higher after you stop receiving Prolia or if you miss a dose. To learn more about the risk of bone fractures, see the “Side effects explained” section above.

Talk with your doctor if you have questions about when specific side effects are expected to start with Prolia. They can also suggest ways to manage side effects that become bothersome.

Do most people tolerate Prolia well?

Yes. Most people who start Prolia continue receiving the drug as long as the benefits of the medication outweigh the side effects.

Many of the mild side effects reported with Prolia should be temporary. Serious side effects aren’t common with Prolia treatment, but they can occur.

If you receive Prolia and have side effects that are difficult to tolerate, be sure to talk with your doctor. They can recommend methods to help relieve your symptoms, or they may prescribe a different medication to treat your condition.

What are the dangers of using Prolia?

Most people who use Prolia don’t have serious side effects. But as with many other drugs, serious side effects can occur with Prolia. For more information, see the “What are the serious side effects of Prolia?” section above.

You could be at higher risk for certain side effects due to other medical conditions you may have. To learn more, see the “Warnings for Prolia” section below.

Does Prolia cause weight gain?

No, it doesn’t cause weight gain. Weight gain wasn’t reported as a side effect in studies of people using Prolia.

However, some people* did report fluid retention (buildup of fluid), which caused swelling in their arms or legs. Swelling can cause weight to increase.

If you experience swelling or are concerned about your weight while using Prolia, talk with your doctor.

* This side effect was reported only in females using Prolia to treat osteoporosis after menopause. In this article, we use the term “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

If I experience side effects from Prolia, can they be reversed?

It’s possible, depending on the side effect. Some Prolia side effects can be treated. For example:

  • Mild pain, such as in the muscles or joints, or a headache. Your doctor may recommend using an over-the-counter pain reliever, such as Tylenol (acetaminophen) or Advil (ibuprofen), to treat this side effect.
  • Bladder infection. For this side effect, your doctor will likely prescribe an antibiotic.
  • Decreased bone production (bones take longer to form new tissue). Bone production typically returns to its usual rate about 24 months after your last dose of Prolia.

Your doctor will choose the best treatment for you based on your health and the side effects Prolia is causing. If you have questions about treating side effects from Prolia, talk with your doctor.

Does Prolia cause hair loss?

In studies, people using Prolia didn’t report hair loss as a side effect.

However, hair loss has been reported by people using Prolia after these studies. So it isn’t known whether Prolia or something else caused the hair loss.

For example, certain cancer treatments can cause hair loss. In people with prostate or breast cancer who are using Prolia, hair loss may be due to using a drug other than Prolia.

If you’re concerned about hair loss while using Prolia, talk with your doctor. They may be able to recommend ways to address this side effect.

Below is important information you should consider before taking Prolia.

Boxed warning: Risk of severely low blood calcium levels

Prolia has a boxed warning. A boxed warning is the most serious warning from the FDA. For details, see the “Side effects explained” section above.

Other warnings

Prolia can sometimes cause harmful effects in people who have certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Prolia is a good treatment option for you.

Talk with your doctor about your health history before you take Prolia. Be sure to tell them if any of the following factors apply to you:

  • planned dental surgery or tooth extraction
  • previous surgery on your thyroid gland or one of your parathyroid glands
  • problems absorbing minerals
  • kidney problems, such as chronic kidney disease
  • previous allergic reaction to Prolia
  • pregnancy
  • breastfeeding
  • alcohol consumption

Q:

Is my risk for bone fractures higher if I leave my osteoporosis untreated instead of using Prolia? I’m worried about taking a drug for weakened bones that may put me at risk for breaking a bone.

Anonymous

A:

Yes, your risk for bone fractures is higher if you leave osteoporosis untreated. In studies, the risk of bone fracture was higher in people who didn’t receive treatment for osteoporosis compared with those who used Prolia.

Additionally, without treatment for osteoporosis, your bones may become weaker.

It’s recommended that you take Prolia as prescribed by your doctor to prevent bone fractures if you have osteoporosis.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.