Januvia (sitagliptin) is a brand-name oral tablet that’s prescribed for type 2 diabetes. As with other drugs, Januvia can cause side effects, such as dizziness. In rare cases, side effects may last long term.

Januvia belongs to a drug class called dipeptidyl peptidase-4 inhibitors. The drug is not available in a generic version.

Read on to learn about potential common, mild, and serious side effects of Januvia. For a general overview of the drug, including details about its uses, see this article.

Januvia can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days or weeks. But 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 Januvia in clinical trials:

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

Mild side effects of Januvia can include:

These side effects may be temporary, lasting a few days or weeks. But 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 Januvia and want to tell the FDA about it, visit MedWatch.

Januvia may cause serious side effects, including some long-term side effects (such as heart failure). The list below may not include all possible serious side effects of the drug. For more information, you can refer to Januvia’s prescribing information.

If you develop serious side effects while taking Januvia, 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 can include:

  • Hypoglycemia (low blood sugar), when Januvia is used with insulin or a sulfonylurea medication such as Glucotrol (glipizide). Symptoms can include:
    • dizziness
    • headache
    • drowsiness
    • confusion
    • sweating
    • fast heart rate
    • irritability or feeling “jittery”
  • Pancreatitis (inflammation in your pancreas). Symptoms can include:
    • severe abdominal pain that doesn’t go away, and may spread to your back
    • vomiting
  • Bullous pemphigoid (a type of skin reaction that may require treatment in the hospital). Symptoms can include:
    • blisters
    • erosion (breakdown) of the outer layer of your skin
  • Sudden kidney failure.*
  • Severe joint pain.*
  • Heart failure.*
  • Allergic reaction.*

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

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

Is weight gain or weight loss a side effect of Januvia?

In clinical trials, neither weight gain nor weight loss was reported as a side effect of Januvia.

But unusually fast weight gain may be a sign of more severe side effects from Januvia. These may include heart failure or kidney problems. If you notice a sudden increase in your weight, call your doctor right away.

If you have other questions about your weight while taking Januvia, talk with your doctor.

Does Januvia have any contraindications?

The only contraindication to taking Januvia is having a past allergic reaction to the drug or any of its ingredients. A contraindication is a factor or condition that prevents you from using a medication.

You can see a full list of Januvia’s ingredients in the drug’s prescribing informationYou can also speak with your pharmacist or doctor if you have more questions about contraindications to Januvia.

Do Januvia’s side effects vary by strength: 25 mg, 50 mg, and 100 mg?

Clinical trials didn’t look at whether side effects varied depending on the strength of Januvia people took. In fact, side effects were only reported for people taking 100 milligrams (mg) of Januvia.

If you have questions about side effects of Januvia’s different strengths, talk with your doctor or pharmacist.

Does Januvia cause yeast infections?

No, yeast infections weren’t reported as a side effect in clinical trials of Januvia.

But sitagliptin, Januvia’s active ingredient, is used in other combination drugs that may cause yeast infections as a side effect. For example, people taking Steglujan (ertugliflozin/sitagliptin) have reported yeast infections as a side effect. Both Steglujan and Januvia are brand-name drugs used to treat type 2 diabetes.

If you have questions about yeast infections while taking Januvia, talk with your doctor.

Is itching one of Januvia’s side effects?

Itching wasn’t reported as a side effect by people taking Januvia in clinical trials.

But itching may be a sign of an allergic reaction, which is a rare but potentially serious side effect of Januvia. If you have other symptoms of an allergic reaction in addition to itching, such as a rash, call your doctor right away. And if you have symptoms that are serious, such as trouble breathing, immediately call 911 or your local emergency number. (See “Side effect specifics” below for a list of allergic reaction symptoms.)

Should I expect hair loss when using Januvia?

No, hair loss wasn’t reported in clinical trials of Januvia. If you have questions about hair loss while taking Januvia, talk with your doctor.

Learn more about some of the side effects that Januvia may cause.

Severe joint pain

It’s possible for Januvia to cause joint pain. This can include severe joint pain, although this is thought to be rare.

Severe joint pain wasn’t seen in clinical trials of Januvia. But Januvia belongs to a class* of drugs called dipeptidyl peptidase-4 (DD-4) inhibitors. And drugs in this class have been reported to cause severe joint pain, though this is thought to be rare.

* A class of drugs is a group of medications that work in a similar way.

What you can do

While taking Januvia, call your doctor if you develop soreness or pain in your joints, including severe joint pain. Your doctor may recommend treatments to help relieve this side effect. Or, they may have you stop taking Januvia and try a different medication.

Severe joint pain typically goes away after stopping treatment with Januvia. You should talk with your doctor before stopping Januvia.

Heart failure

People taking Januvia in clinical trials didn’t report heart failure as a side effect. But according to the Food and Drug Administration (FDA), diabetes drugs similar to Januvia have been shown to increase the risk of heart failure. These drugs include Nesina (alogliptin) and Onglyza (saxagliptin). Like Januvia, these medications belong to a class of drugs called DD-4 inhibitors.

Symptoms of heart failure can include:

  • Shortness of breath.
  • Fluid retention (too much fluid in your body), which can lead to:
    • swelling, especially in your feet or ankles
    • rapid weight gain
  • Fatigue.

What you can do

Your doctor will monitor you for heart failure while you’re taking Januvia. Call your doctor right away if you notice any symptoms of heart failure.

If you’ve had heart failure in the past, be sure to tell your doctor before you begin taking Januvia. They may recommend a drug other than Januvia for you.

Sudden kidney failure

Acute (sudden) kidney failure wasn’t reported in clinical trials of Januvia. But there have been reports of this condition in people taking the drug since it was approved. In rare cases, kidney failure may be severe enough to require dialysis treatment.

Symptoms of acute kidney failure can include:

  • chest pain or pressure
  • swelling in your ankles, feet, or legs
  • fatigue
  • not producing as much urine as usual

What you can do

Before you start taking Januvia, you’ll likely have a kidney function test. Your doctor may also recommend having these tests during your treatment. Based on your test results, your doctor may adjust your Januvia dosage as needed to make sure the drug doesn’t harm your kidneys.

If you experience symptoms of sudden kidney failure, call your doctor right away. This may need to be treated with dialysis. Your doctor will likely have you stop taking Januvia and try a different diabetes drug instead. This may help your kidney function return to how it was before the kidney failure occurred.

Allergic reaction

As with most drugs, Januvia can cause an allergic reaction in some people. Symptoms can be mild or serious and can include:

  • 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 Januvia. But 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 Januvia. 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 are described below.

Pancreatitis. Although rare, Januvia may cause pancreatitis. It isn’t known whether people who have had pancreatitis before may be at higher risk for this side effect. Be sure to talk with your doctor about your history of pancreatitis before you start taking Januvia. They may recommend a different treatment for you.

Kidney problems. In rare cases, Januvia can cause sudden kidney failure. If you have kidney problems, you may be at higher risk for this side effect. And people with kidney problems may need a lower dosage of Januvia. For this reason, be sure your doctor is aware if you have kidney problems before you start taking Januvia. Other treatments may be better choices for you.

Heart failure. Januvia can cause heart failure, and can make this condition worse if you already have it. If you have heart failure, make sure your doctor knows this before you begin treatment with Januvia. They may recommend a drug other than Januvia.

Allergic reaction. You should not take Januvia if you’ve ever had an allergic reaction to Januvia or any of its ingredients. Talk with your doctor about which other treatments are better choices for you.

Alcohol with Januvia

There aren’t any direct interactions between Januvia and alcohol.

However, drinking excessive amounts of alcohol can decrease your blood sugar levels. Since Januvia also works to lower blood sugar, drinking alcohol while you’re taking the drug may lead to hypoglycemia (low blood sugar).

Also, drinking too much alcohol may damage your pancreas. This may increase your risk for pancreatitis (inflammation of your pancreas), which is a possible side effect of Januvia.

If you drink alcohol, talk with your doctor about how much, if any, is safe for you to drink while you’re taking Januvia.

Pregnancy and breastfeeding while taking Januvia

Below is information on Januvia’s use during pregnancy and while breastfeeding.

Pregnancy. It isn’t known if Januvia is safe for use during pregnancy. The drug’s use during pregnancy hasn’t been studied in humans. Januvia didn’t cause problems when given to pregnant females in animal studies. But animal studies don’t always predict what will happen in people. If you’re pregnant or planning to become pregnant, make sure to talk with your doctor before starting Januvia treatment.

A pregnancy registry was available for people taking Januvia during pregnancy, but enrollment recently ended. Pregnancy registries collect information about drug use during pregnancy to help doctors learn more about the drug’s safety. If you’re taking Januvia during pregnancy, or if you were previously exposed to the drug during pregnancy, you still can contact the drug manufacturer by calling 877-888-4231.

Breastfeeding. It isn’t known whether Januvia is safe to take while breastfeeding, or whether the drug passes into human breast milk. In animal studies, the drug was shown to pass into the milk of lactating animals, but it didn’t cause harm to offspring. However, animal studies don’t always predict what will happen in people. Talk with your doctor about feeding options for your child while taking Januvia.

Januvia doesn’t usually cause side effects. When they do occur, they’re usually mild. Most mild side effects of the drug go away with time and don’t require medical attention.

In rare cases, Januvia may cause serious side effects. You should talk with your doctor if you have symptoms of:

You should also talk with your doctor if you become pregnant while taking Januvia.

If you’d like to learn more about Januvia, 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.