Actonel (risedronate) is a prescription drug used to prevent and treat certain conditions related to bone health. Actonel can cause side effects that range from mild to serious, including some that affect your jaws and teeth.

Specifically, Actonel is used in adults to:

Actonel comes as an oral tablet and contains the active ingredient risedronate.

Keep reading to learn about the common, mild, and serious side effects Actonel can cause. For a general overview of the drug, including details about its uses, see this article.

Some people may experience mild to serious side effects during Actonel treatment. Examples of the drug’s commonly reported side effects include:

Mild side effects have been reported with Actonel. These include:

  • pain, including in the abdomen, back, bones, muscles, and joints
  • indigestion
  • dizziness
  • swelling in the nose
  • sore throat
  • diarrhea
  • weakness
  • mild skin rash
  • headache
  • constipation

In most cases, these side effects should be temporary. And some may be easily managed. But if you have symptoms that are ongoing or bothersome, talk with your doctor or pharmacist. And do not stop taking Actonel unless your doctor recommends it.

Actonel may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

While rare, serious side effects have been reported with Actonel. These include:

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

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

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

Allergic reaction

For some people, Actonel can cause an allergic reaction. These reactions weren’t common in the drug’s studies, though.

In general, symptoms of allergic reaction can be mild or serious. You can learn more about possible symptoms in this article.

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 and can determine whether you should keep taking Actonel.

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’ve had a serious allergic reaction to Actonel, they may have you switch to a different treatment.

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

Does Actonel cause different side effects when used once per week? What about once per month?

No, Actonel isn’t expected to cause different side effects based on how frequently it’s taken. Across studies, similar side effects were reported in people taking Actonel daily, weekly, or monthly.

That said, there are some slight differences in how often certain side effects may occur based on your Actonel dosing schedule. There’s a slightly higher risk of developing side effects when you first start treatment if you take Actonel once per month versus once per day. Examples of these side effects include fever and flu-like symptoms.

In studies, people were more likely to stop taking Actonel due to abdominal pain or diarrhea if they took Actonel once per month than if they took it once per day.

Talk with your doctor or pharmacist if you’d like to learn more about how your Actonel dosage may affect your risk of side effects.

How long do Actonel side effects last? Can Actonel cause long-term side effects?

It depends. In most cases, side effects caused by Actonel are mild and go away on their own within a few hours or days.

However, long-term side effects are possible with Actonel treatment. Long-term side effects are side effects that appear after you’ve taken the drug for a long time, or they may last for a long time even after you stop treatment.

Examples of long-term side effects reported with Actonel include:

  • low blood calcium level
  • osteonecrosis of the jaw*
  • unusual bone fractures*
  • severe esophageal side effects*

For more information about Actonel and your particular risk of long-term side effects, talk with your doctor or pharmacist.

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

Can Actonel cause different side effects in elderly people?

No, it’s not thought so. In Actonel studies, different side effects weren’t reported in people ages 65 years and older than in younger adults.

However, adults ages 65 years and above are more likely to have multiple health conditions and to take multiple medications. While these factors can increase your risk of side effects from Actonel, your age itself isn’t expected to.

To learn more about your risk of side effects from Actonel and factors that influence it, talk with your doctor or pharmacist.

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

Osteonecrosis of the jaw (ONJ)

ONJ has happened in people taking Actonel, but it was rare. This side effect didn’t occur in Actonel studies but has happened since the drug was approved for use. It’s a known side effect of bisphosphonates (the group of drugs Actonel belongs to).

With ONJ, parts of your jawbone become exposed through your gums. If you don’t receive treatment, the exposed portions of jawbone may die as a result of inadequate blood supply. Symptoms can include:

  • loose teeth
  • mouth pain
  • swelling in your gums and soft tissue
  • exposed jawbone

ONJ can occur at any time during Actonel treatment, but your risk may increase with long-term use.

Other factors that can increase the risk of ONJ when taking this drug include:

  • undergoing invasive dental procedures (such as tooth extraction) during treatment
  • having poor dental health
  • having certain other medical conditions, such as:
    • anemia (low level of red blood cells)
    • cancer
    • preexisting dental problems
  • taking certain other medications, including corticosteroids such as prednisone

What might help

If you need to have an invasive dental procedure while taking Actonel, your doctor may have you temporarily stop Actonel before the procedure.

If you develop symptoms of ONJ during Actonel treatment, talk with your doctor immediately. They’ll likely refer you to an oral surgeon who can evaluate and treat the condition. They may also suggest stopping treatment with Actonel.

Unusual bone fractures

Treatment with bisphosphonates, including Actonel, increases your risk of unusual bone fractures (breaks) in your femur (thigh bone). It doesn’t appear that this side effect was reported in Actonel studies, but it has happened since the drug was approved for use. While rare, this side effect can be serious.

These fractures are called “unusual” because they typically happen with very little or no trauma to the affected bone. Unusual bone fractures may occur at any time during Actonel treatment.

The key symptom of this side effect is any new or unusual pain in your thigh, groin, or hip. This side effect often causes a dull, aching pain in the thigh weeks or months before the break happens.

What might help

If you develop new or unusual pain in your thigh, groin, or hip, immediately tell your doctor. They’ll likely want to examine your symptoms in person. They’ll order imaging and other tests as needed to determine whether you have an unusual femur fracture. If they confirm that you have a fracture, they may have you stop taking Actonel.

Severe esophageal side effects

Like other bisphosphonates, Actonel can cause irritation to your upper digestive tract, including your esophagus. It’s not clear whether this side effect occurred in Actonel studies, but it has happened since the drug was approved for use.

Examples of esophageal side effects, which can be severe, that can happen with Actonel treatment include:

Symptoms vary depending on the specific side effect. Key symptoms to watch for include new or worsening heartburn, pain or difficulty swallowing, and retrosternal chest pain.

Esophageal side effects are possible because Actonel tablets can be very irritating to your upper digestive tract, especially your esophagus.

Not following the full directions for taking Actonel (see “What might help” just below) is one risk factor for this side effect. Other risk factors include existing problems with your upper digestive tract, such as Barrett’s esophagus and existing esophageal ulcers.

What might help

There are ways to lower your risk of severe esophageal side effects while taking Actonel. Be sure to follow these instructions with every dose:

  • Take your Actonel dose while standing or sitting up.
  • Do not lie down for at least 30 minutes after taking a dose.
  • Always take your Actonel dose with at least 6 to 8 ounces of water.
  • Never chew or suck on Actonel tablets.

If you develop symptoms of esophageal side effects, immediately contact your doctor. Do not take another dose of Actonel unless they instruct you to do so. Your doctor will likely want to evaluate your symptoms in person. Depending on their findings, they may have you permanently stop treatment with Actonel.

Keeping track of side effects

During your Actonel treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start a new drug or combination of treatments.

Your side effect notes can include things such as:

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

Sharing notes with your doctor will help them learn more about how Actonel affects you. They can then use this information to adjust your treatment plan if needed.

Actonel can sometimes cause harmful effects in people with certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether this drug is a good treatment option for you. Talk with your doctor about your health history before starting Actonel. Be sure to tell them if any of the following factors apply to you:

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.