Fosamax (alendronate) is a brand-name prescription medication. The Food and Drug Administration (FDA) has approved it to:

Here are some fast facts about Fosamax:

  • Active ingredient: alendronate
  • Drug class: bisphosphonate
  • Drug form: oral tablet

In most cases, Fosamax is a long-term treatment. However, the drug does have a limitation of use. It’s not known exactly how long it may be safe to take Fosamax. The manufacturer recommends that certain people at low risk of bone fracture take the drug for 3 to 5 years before stopping treatment. However, your doctor will help determine the best treatment plan for you.

As with other drugs, Fosamax can cause side effects. Read on to learn about potential common, mild, and serious side effects. For a general overview of Fosamax, including details about its uses, see this article.

* Sex and gender exist on spectrums. Use of the terms “female” and “male” in this article refers to sex assigned at birth.

Fosamax vs. Fosamax Plus D

Fosamax and Fosamax Plus D both contain the same active drug, alendronate. However, Fosamax Plus D also has vitamin D in it. Fosamax and Fosamax Plus D are approved to treat osteoporosis in postmenopausal females,* or to treat osteoporosis in males.* In addition, Fosamax is also approved to:

  • prevent osteoporosis in postmenopausal females
  • treat osteoporosis due to glucocorticoid use
  • treat Paget’s disease of bone

Fosamax Plus D isn’t currently approved for these uses.

Side effects of these medications are very similar, since both drugs contain alendronate. This article will focus on Fosamax. If you have questions about taking Fosamax Plus D, talk with your doctor or pharmacist.

* Sex and gender exist on spectrums. Use of the terms “female” and “male” in this article refers to sex assigned at birth.

Fosamax pills can cause certain side effects (also called adverse effects), some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Fosamax in clinical trials:

* For more information about this side effect, see “Side effect specifics” below.

Mild side effects can occur with Fosamax use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Fosamax’s prescribing information.

Mild side effects that have been reported with Fosamax include:

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect while taking Fosamax and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.

Fosamax may cause serious side effects. In most cases, serious side effects from Fosamax are rare, but they can occur. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Fosamax’s prescribing information.

If you develop serious side effects while taking Fosamax, 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.

Serious side effects that have been reported and their symptoms include:

* For more information about this side effect, see “Side effect specifics” below.

It’s possible that older adults (ages 65 years and older) taking Fosamax may be at a higher risk of side effects from the drug. However, in clinical trials, Fosamax was just as safe in older adults as compared with younger people who took the drug.

If you have additional questions about side effects that you may experience, talk with your doctor.

Fosamax may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Does Fosamax cause any teeth-related side effects?

Yes, it’s possible for Fosamax to cause teeth-related side effects. Although very rare, it’s possible for this medication to cause jaw osteonecrosis. Osteonecrosis is a condition where your bone tissue doesn’t get enough blood supply and eventually dies. This condition may cause dental symptoms such as:

  • loose teeth
  • jaw pain
  • exposed jawbone in your mouth
  • numbness of the jaw

If you have symptoms of jaw osteonecrosis, talk with your doctor right away. They will recommend that you see an oral surgeon who can help manage your condition.

If you develop jaw osteonecrosis, your doctor may recommend stopping Fosamax treatment. In this case, they may recommend a different treatment option for you.

For more information about jaw osteonecrosis, see the “Side effect specifics” section below.

Is weight gain a side effect of Fosamax treatment?

No, you shouldn’t experience weight gain from taking Fosamax. This wasn’t a side effect that people taking Fosamax reported in clinical trials.

However, swelling of the arms or legs (edema) was reported after Fosamax was FDA approved. And it’s possible for edema to cause weight gain.

If you notice weight gain during your treatment with Fosamax, talk with your doctor. They can help determine if you have edema that’s causing weight gain or what else may be causing your weight gain. In addition, they can recommend ways to help manage your weight.

Are side effects of Fosamax and its generic version (alendronate) the same?

Yes, side effects of Fosamax and its generic form, alendronate, are likely the same. Both drugs contain the same active ingredient, alendronate. So this means that the side effects will likely be similar.

However, in addition to active ingredients, drugs also contain inactive ingredients. For example, drugs may also contain fillers or coatings. And it’s possible to have an allergic reaction or other side effects from these inactive ingredients.

If you have questions or concerns about side effects from Fosamax or its generic form, talk with your doctor or pharmacist.

What are the long-term side effects of Fosamax?

Although rare, it’s possible to experience long-term side effects from Fosamax. Examples of long-term side effects may include:

These side effects may start during your treatment with Fosamax and continue throughout your treatment. If you have concerns about experiencing long-term side effects from taking Fosamax, talk with your doctor or pharmacist.

Should I expect hair loss during Fosamax treatment?

It’s possible that you may have hair loss during your treatment with Fosamax. This wasn’t a side effect that was reported in clinical trials of people taking Fosamax.

However, hair loss was reported after the drug was FDA approved. So, it’s not known for sure if hair loss may be related to Fosamax treatment.

If you notice hair loss during your treatment with Fosamax, tell your doctor. They can help determine what may be causing your hair loss. They may also be able to recommend ways to treat hair loss. For example, they may recommend using an over-the-counter medication, such as Rogaine (minoxidil).

Learn more about some of the side effects that Fosamax may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Fosamax.

Jaw osteonecrosis

Although rare in clinical trials, it’s possible for jaw osteonecrosis to occur from taking Fosamax. Osteonecrosis is a condition where your bone tissue doesn’t get enough blood supply and eventually dies.

Although this can happen without a cause, most cases of jaw osteonecrosis occur after a dental procedure, in people with poor oral hygiene, or in people with other conditions that may increase your risk. Examples of these other conditions may include anemia, dental disease, or infection. Your risk may also be higher if you’ve taken Fosamax for a long period of time.

Symptoms of jaw osteonecrosis may include:

  • loose teeth
  • jaw pain
  • exposed jawbone in your mouth
  • numbness of the jaw

What you can do

Before you start taking Fosamax, your doctor will recommend seeing your dentist or having a mouth examination done. If you need to have any dental work, tell your dentist that you’re taking Fosamax. In some cases, they may recommend pausing your Fosamax treatment until after your procedure.

If you do develop jaw osteonecrosis, see your doctor right away. They will recommend that you see an oral surgeon who can help manage your condition.

If you develop jaw osteonecrosis, your doctor may recommend stopping treatment with Fosamax. In this case, they may recommend a different treatment option for you.

Bone pain

It’s possible to develop bone pain from taking Fosamax. Bone pain was a common side effect reported in clinical trials of the drug. In most cases, bone pain is mild. However, it’s also possible to experience severe bone pain from taking Fosamax. Bone pain or muscle pain was reported most often in postmenopausal females.*

Bone pain was reported in clinical trials as early as one day after starting treatment. However, some people also reported bone pain occurring months after starting Fosamax.

What you can do

If you develop bone pain from taking Fosamax, tell your doctor. In some cases, bone pain can be due to fracture. So your doctor will want to make sure that your bone pain is from Fosamax.

If you have severe bone pain, your doctor may recommend stopping treatment with Fosamax. In this case, they may recommend a different treatment option for you.

* Sex and gender exist on spectrums. Use of the term “female” in this article refers to sex assigned at birth.

Constipation

You may experience constipation from taking Fosamax. In fact, constipation was one of the most common side effects reported in clinical trials. Symptoms of constipation may include passing hard, lumpy stools and straining to use the bathroom.

What you can do

If you notice constipation from taking Fosamax, talk with your doctor or pharmacist. They may be able to recommend treatment options to help manage your constipation. For example, they may recommend taking an over-the-counter treatment, such as MiraLAX (polyethylene glycol). However, it’s important to note that you should wait at least 30 minutes after taking Fosamax to take any other medications.

Indigestion

It’s possible to develop indigestion from taking Fosamax. Indigestion is a common side effect reported in clinical trials of Fosamax.

Indigestion may also be called dyspepsia. This condition can cause symptoms such as:

  • pain or discomfort in your stomach
  • nausea
  • bloating
  • burning feeling in your abdomen or stomach

What you can do

If you develop indigestion during your treatment with Fosamax, talk with your doctor or pharmacist. They may want to make sure that your indigestion isn’t related to a more serious side effect, such as stomach or esophagus ulcers.

Symptoms of stomach or esophagus ulcers may include chest pain or worsening heartburn. Although chest pain may occur from taking Fosamax, this drug isn’t known to cause cardiac side effects. Instead, this side effect may be due to esophagus or stomach ulcers. Your doctor can help make sure that you’re not experiencing a more serious condition.

You doctor may be able to recommend a treatment option for your indigestion. For example, they may recommend taking a proton pump inhibitor, such as Nexium (esomeprazole) or an antacid, such as Tums (calcium carbonate). It’s important to note that you should wait at least 30 minutes after taking Fosamax to take any other medications.

Allergic reaction

As with most drugs, Fosamax can cause an allergic reaction in some people. It’s not known how often allergic reactions occurred in clinical trials.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your, lips, hands, or feet
  • ocular (eye-related) side effects, such as swelling of your eyelid
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Fosamax. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you take Fosamax. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. These are considered drug-condition or drug-factor interactions. The conditions and factors to consider include:

Esophagus or stomach problems. Tell your doctor about any esophagus or stomach problems that you have before taking Fosamax. This medication can cause esophagus ulcers or stomach bleeding to occur. And if you already have an esophagus or stomach problem, taking Fosamax may make your condition worse. Your doctor can help determine whether this drug may be a safe treatment option for you.

Trouble standing or sitting up for 30 minutes. After taking your dose of Fosamax, you should stand or sit in an upright position for 30 minutes. Lying down within 30 minutes of taking Fosamax can cause an ulcer to develop in your esophagus. So if you have trouble standing or sitting up for 30 minutes, your doctor may recommend a different treatment option for you.

Upcoming dental procedure. If you have an upcoming dental procedure, including a tooth removal, tell your doctor that you’re taking Fosamax before the procedure. It’s possible that your doctor may recommend stopping Fosamax before your dental procedure to decrease your risk of side effects. Having a dental procedure while taking Fosamax can increase your risk of jaw osteonecrosis.

Allergic reaction. If you’ve had an allergic reaction to Fosamax or any of its ingredients, your doctor will likely not prescribe Fosamax. Ask your doctor what other medications may be better options for you.

Low blood calcium levels. If you have low blood calcium levels, your doctor may recommend increasing your calcium before starting Fosamax. This may be done by taking a calcium supplement. You should not take Fosamax if you have a low blood calcium level because Fosamax can also cause low blood calcium levels to occur. And if you already have low levels, taking Fosamax may make your levels worse. Before you start taking Fosamax, your doctor will discuss increasing your calcium levels, if they are low.

Difficulty swallowing. If you have problems swallowing tablets, tell your doctor before taking Fosamax. This medication is available as a tablet that needs to be swallowed. If the drug begins to dissolve in your mouth or throat, you may be at risk of an esophagus ulcer. In this case, your doctor may recommend that you take the liquid form of alendronate, which is the active drug in Fosamax. Brand-name Fosamax is only available in 70 mg tablets at this time, so this article discusses side effects of Fosamax 70 mg tablets. However, if you have trouble swallowing, talk with your doctor about switching to liquid alendronate.

Kidney problems. Tell your doctor about any kidney problems you have before starting treatment with Fosamax. Your body removes Fosamax through your kidneys. And if your kidneys aren’t working like they should, it’s possible that Fosamax may build up in your body. This can cause side effects to occur. Your doctor can help determine if Fosamax is safe for you based on your kidney condition.

Malabsorption syndrome. Tell your doctor if you have malabsorption syndrome, or a condition that decreases your body’s ability to absorb minerals. Fosamax can cause low blood calcium levels to occur. And if you have malabsorption syndrome, you may be at an even higher risk of low blood calcium. This can be serious. In this case, your doctor may recommend monitoring your calcium levels more often. In some cases, they may recommend a different treatment option for you.

Alcohol with Fosamax

Fosamax isn’t known to interact with alcohol.

However, it’s possible that drinking large amounts of alcohol over time can increase your risk of osteoporosis. If you already have osteoporosis, drinking alcohol may make your condition worse. Alcohol can change the way that your body absorbs calcium and vitamin D, which can worsen your symptoms of osteoporosis.

In addition, heavy alcohol use can also cause lower levels of testosterone in males* or estrogen in females.* Lower levels of these hormones can increase your risk of osteoporosis. Alcohol also can increase another hormone called cortisol, which also can decrease your body’s ability to make bone.

Alcohol can also increase your risk of falling. And if you have osteoporosis, falling may cause fractures to occur.

In addition, it’s important to note that you should not eat, drink, or take any other medications within 30 minutes of your Fosamax dose. So make sure you wait at least 30 minutes after your Fosamax dose before drinking any alcohol.

If you have questions about drinking alcohol while taking Fosamax, talk with your doctor or pharmacist.

* Sex and gender exist on spectrums. Use of the terms “female” and “male” in this article refers to sex assigned at birth.

Pregnancy and breastfeeding while taking Fosamax

It’s not known if it’s safe to take Fosamax during pregnancy or while breastfeeding.

At this time, there aren’t enough studies to determine if Fosamax may be safe during pregnancy, or what risks the drug may cause. So it’s recommended that you stop treatment with Fosamax if you do become pregnant while taking the drug.

Animal studies show that the drug may increase the risk of pregnancy loss or bone problems occurring in baby animals. However, animal studies don’t always indicate what may happen in humans.

In addition, it’s not known if Fosamax is safe to take while breastfeeding. It’s not known if the drug passes into breast milk or what effects it may have on a breastfed child.

If you’re pregnant, planning to become pregnant, or breastfeeding, talk with your doctor before taking Fosamax. They can help determine the best treatment plan for you.

In most cases, side effects of Fosamax are mild. However, this drug may cause serious side effects, as well.

If you’d like to learn more about Fosamax, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

Disclaimer: Medical News Today 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.