Janumet and Janumet XR (sitagliptin/metformin) are brand-name prescription medications. They’re approved by the Food and Drug Administration (FDA) to treat type 2 diabetes in adults.

Janumet and Janumet XR are typically used for the long-term management of blood sugar levels. They’re used in combination with diet and exercise.

Here are some fast facts about Janumet and Janumet XR:

Like other drugs, Janumet and Janumet XR can cause side effects. Read on to learn about potential common, mild, and serious side effects. For a general overview of these drugs, see this article.

Janumet and Janumet XR can cause certain side 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 Janumet or Janumet XR in clinical trials:

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

Mild side effects can occur with Janumet and Janumet XR use. This list doesn’t include all possible mild side effects of the drug. For further details, you can refer to the prescribing information for Janumet and Janumet XR.

Mild side effects that have been reported with Janumet and Janumet XR 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 and reviews side effects of the medication. If you develop a side effect while taking Janumet or Janumet XR and want to tell the FDA about it, visit MedWatch.

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

Janumet and Janumet XR may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to the prescribing information for Janumet and Janumet XR.

If you develop serious side effects while taking Janumet or Janumet XR, 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:

* This side effect wasn’t reported in clinical trials of Janumet and Janumet XR. However, it has been reported since the drugs became available for use.
** Janumet and Janumet XR have a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effect specifics” section below.
† For more information about this side effect, see “Side effect specifics” below.
‡ An allergic reaction is possible after taking Janumet and Janumet XR. However, this side effect wasn’t reported in clinical trials of Janumet and Janumet XR.

Janumet and Janumet XR may cause several side effects. Here are some frequently asked questions about the drugs’ side effects and their answers.

Do Janumet and Janumet XR’s side effects include pancreatic cancer?

Pancreatic cancer wasn’t reported as a side effect in clinical trials of Janumet and Janumet XR.

There have been reports of a link between sitagliptin* and pancreatic cancer. However, more evidence is needed to confirm whether sitagliptin may cause pancreatic cancer.

On the other hand, pancreatitis (inflammation of the pancreas) has been reported since Janumet and Janumet XR became available for use.

It’s important to note that diabetes may increase the risk of pancreatic cancer. Since Janumet and Janumet XR are prescribed to treat type 2 diabetes, you may have a higher risk of pancreatic cancer while taking the drugs. However, this risk is likely due to diabetes rather than Janumet or Janumet XR.

To learn more about pancreatic cancer, Janumet, and Janumet XR, talk with your doctor.

* Sitagliptin is one of the active ingredients in Janumet and Janumet XR.

Can Janumet and Janumet XR cause hair loss, blurred vision, or erectile dysfunction?

Probably not. Hair loss, blurred vision, and erectile dysfunction weren’t reported as side effects in clinical trials of Janumet and Janumet XR.

However, keep in mind that diabetes may cause hair loss, blurred vision, and erectile dysfunction. Janumet and Janumet XR are prescribed to treat type 2 diabetes. So, you may experience these conditions while taking the drugs. However, they’re likely related to diabetes instead of Janumet and Janumet XR.

Talk with your doctor or pharmacist if you have questions about hair loss, blurred vision, and erectile dysfunction with diabetes, Janumet, or Janumet XR.

How long do Janumet and Janumet XR’s side effects last?

The length of time side effects last with Janumet and Janumet XR will differ for each person.

In general, the side effects of a drug should go away within days or weeks. This is because side effects are less likely to happen as your body gets used to a drug.

To learn more about what to expect with Janumet or Janumet XR, talk with your doctor or pharmacist.

Are weight loss or weight gain side effects of Janumet and Janumet XR?

Weight loss and weight gain weren’t reported as side effects in clinical trials of Janumet and Janumet XR.

However, weight loss is known to occur with metformin (one of the active ingredients in Janumet and Janumet XR). In fact, metformin is sometimes prescribed off-label for weight loss. (Off-label drug use is when an FDA-approved drug is prescribed for a purpose other than what it’s approved for.) However, Janumet and Janumet XR aren’t used for weight loss.

Keep in mind that rapid unintentional weight gain is a symptom of heart failure. This side effect wasn’t reported in clinical trials of Janumet and Janumet XR. However, there have been reports of heart failure with other dipeptidyl peptidase-4 (DPP-4) inhibitors. (Sitagliptin is one of the active ingredients in Janumet and Janumet XR. And it is a DPP-4 inhibitor.)

Tell your doctor right away if you have sudden weight gain with Janumet or Janumet XR. They’ll likely check for other symptoms of heart failure.

To learn more about possible weight changes with Janumet or Janumet XR, talk with your doctor or pharmacist.

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

Diarrhea

Janumet and Janumet XR may cause diarrhea. This was one of the most common side effects in clinical trials of Janumet and Janumet XR.

What you can do

It’s recommended that you take Janumet or Janumet XR with a meal. This can help ease any diarrhea you may have while taking these medications.

Janumet comes as an immediate-release (short-acting) oral tablet, while Janumet XR comes as an extended-release (long-acting) oral tablet. This means Janumet XR is released more slowly into your body than Janumet is. For this reason, digestive problems (such as diarrhea) may be less common with Janumet XR than with Janumet.

If you take Janumet and you’re interested in taking Janumet XR instead, talk with your doctor. They can advise which form of Janumet is best for you. Your doctor can also suggest other ways to ease your diarrhea.

Upper respiratory infection

Janumet and Janumet XR may cause upper respiratory infection. This was a more common side effect in clinical trials of Janumet and Janumet XR.

The common cold is an example of an upper respiratory infection. However, specific infections that occurred in clinical trials of Janumet and Janumet XR aren’t known.

Symptoms of upper respiratory infection can include:

What you can do

If you have symptoms of an upper respiratory infection, talk with your doctor. They can suggest ways to ease your symptoms. For example, they may recommend taking over-the-counter (OTC) medications.

However, before taking any OTC medications with Janumet or Janumet XR, talk with your doctor or pharmacist. They can make sure these medications are safe to take with Janumet or Janumet XR.

Headache

Janumet and Janumet XR may cause headache. This was one of the most common side effects in clinical trials of Janumet and Janumet XR.

Keep in mind that headache can be a symptom of hypoglycemia (low blood sugar), which is another possible side effect of Janumet and Janumet XR. For details, see “Hypoglycemia” just below.

What you can do

If you have a bothersome or severe headache with Janumet and Janumet XR, talk with your doctor. They can suggest ways to manage this side effect.

Hypoglycemia

Hypoglycemia (low blood sugar) can occur with Janumet and Janumet XR.

In clinical trials of Janumet and Janumet XR, this side effect was more common when the drugs were used in combination with certain diabetes medications.Examples include:

Whether you’re taking Janumet or Janumet XR alone or in combination with other diabetes medications, watch for symptoms of hypoglycemia. Possible symptoms include:

What you can do

If you have symptoms of low blood sugar with Janumet or Janumet XR, tell your doctor right away. They may adjust the dosage of other diabetes medications you’re taking.

Lactic acidosis

Janumet and Janumet XR have a boxed warning for lactic acidosis. A boxed warning is a serious warning from the Food and Drug Administration (FDA). It alerts patients and doctors about possible dangerous side effects of a drug.

Lactic acidosis is a dangerous buildup of lactic acid in your body. In rare cases, it can be fatal. This side effect wasn’t reported in clinical trials of Janumet and Janumet XR. However, lactic acidosis is a known risk of metformin (one of the active ingredients in Janumet and Janumet XR).

Symptoms of lactic acidosis can include abdominal or muscle pain, trouble breathing, and sleepiness.

Several factors can increase your risk of lactic acidosis with Janumet and Janumet XR. These include:

What you can do

Before taking Janumet or Janumet XR, tell your doctor about all other health conditions you have, medications you take, and procedures you have planned. They can discuss whether these factors may increase your risk of lactic acidosis.

If you have symptoms of lactic acidosis, stop taking Janumet or Janumet XR and tell your doctor right away. If your symptoms seem severe or life threatening, call 911 or your local emergency number right away.

Allergic reaction

As with most drugs, Janumet and Janumet XR can cause an allergic reaction in some people. This side effect wasn’t reported in clinical trials of Janumet and Janumet XR. However, it has been reported since sitagliptin (one of the drugs’ active ingredients) became available for use.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your lips, eyelids, feet, or hands
  • 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 Janumet or Janumet XR. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Below are details about warnings regarding whether Janumet and Janumet XR can be taken safely.

Boxed warning: Lactic acidosis

This drug has a boxed warning for risk of lactic acidosis. This is a serious warning from the Food and Drug Administration (FDA). For details, see the “Side effect specifics” section above.

Other precautions

Be sure to talk with your doctor about your health history before you take Janumet and Janumet XR. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. The conditions and factors to consider include:

Heart failure. Before starting treatment with Janumet or Janumet XR, tell your doctor if you have heart failure. These medications can cause new or worsening heart failure. Your doctor will discuss whether it’s safe for you to take Janumet or Janumet XR.

Low level of vitamin B12. Janumet and Janumet XR may cause a low level of vitamin B12. If you already have a low B12 level, these medications could worsen your condition. Be sure to tell your doctor if you have a low level of vitamin B12. They may watch your B12 levels more closely than usual during treatment with Janumet or Janumet XR.

Kidney problems. Before taking Janumet or Janumet XR, tell your doctor if you have kidney problems, such as kidney failure. Kidney problems can increase your risk of lactic acidosis with these drugs. Janumet and Janumet XR may also cause kidney problems as a side effect. Due to these risks, your doctor may not prescribe Janumet or Janumet XR if you have kidney problems.

Imaging tests. Tell your doctor if you have a planned imaging test that uses iodine contrast. (With this type of test, a healthcare professional injects iodine into your vein before performing the test.) An example is a computerized tomography (CT) scan. Your doctor will recommend if it’s safe to take Janumet or Janumet XR before this type of imaging test.

Planned surgery. Tell your doctor if you have any planned surgeries before starting treatment with Janumet or Janumet XR. Certain surgeries may require you to follow a limited diet or fast. In this case, your doctor may recommend that you stop taking Janumet or Janumet XR around the time of your surgery. This will help lower your risk of hypoglycemia (low blood sugar) while you’re following a limited diet or fasting.

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

Alcohol and Janumet and Janumet XR

Drinking large amounts of alcohol while taking Janumet or Janumet XR can increase your risk of lactic acidosis* as a side effect. For this reason, it’s best to avoid drinking a large amount of alcohol with these medications.

If you drink alcohol, talk with your doctor about how much (if any) is safe to consume while taking Janumet or Janumet XR.

* Janumet and Janumet XR have a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effect specifics” section above.

Pregnancy and breastfeeding while taking Janumet and Janumet XR

It isn’t known if Janumet or Janumet XR is safe to take while pregnant or breastfeeding. There haven’t been enough studies on these drugs during pregnancy and breastfeeding to know for sure.

If you’re pregnant, breastfeeding, or planning for either, talk with your doctor. They can discuss with you the risks and benefits of taking Janumet or Janumet XR.

If you do take Janumet or Janumet XR while pregnant, your doctor may suggest you enroll in a pregnancy registry. These collect information about the safety of medications when used during pregnancy. For details, talk with your doctor or call 800-986-8999.

Both mild and serious side effects may occur with Janumet and Janumet XR. However, most of the drugs’ side effects are expected to be mild and should go away with time. If you have side effects that are bothersome during Janumet and Janumet XR treatment, talk with your doctor.

If you’d like to learn more about Janumet and Janumet XR, 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.