Sitagliptin/metformin | Side Effects, Dosage, Uses & More
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Generic Name:

metformin-sitagliptin, Oral tablet

All Brands

  • Janumet
SECTION 1 of 4

Highlights for metformin-sitagliptin

Oral tablet
1

Sitagliptin/metformin is an oral drug. It’s used along with diet and exercise to control high blood sugar levels caused by type 2 diabetes.

2

Sitagliptin/metformin is available as the name-brand drugs called Janumet and Janumet XR. It’s not available as a generic drug.

3

This drug can cause low blood sugar (hypoglycemia). You should carry a quick source of sugar with you in case this happens. Examples include hard candy and glucose tablets.

4

You’ll need to learn how to test your blood sugar levels at home. You’ll also need to learn how to spot the symptoms of low and high blood sugar, and how to treat these conditions.

5

Sitagliptin/metformin extended-release tablets are not always fully dissolved by your body and can be passed in your stool. Tell your doctor if you keep seeing tablets in your stool.

IMPORTANT INFORMATION

FDA warning

This drug has a Black Box Warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning alerts doctors and patients to potentially dangerous effects.

Lactic acidosis warning: Lactic acidosis is a rare but serious side effect of metformin. In this condition, lactic acid builds up in your blood. This is a medical emergency that requires treatment in the hospital. Lactic acidosis is fatal in about half of people who develop it. You should stop taking metformin and call your doctor right away or go to the emergency room if you have symptoms of lactic acidosis. These include:

  • tiredness
  • weakness
  • unusual muscle pain
  • trouble breathing
  • unusual sleepiness
  • stomach pains, nausea, or vomiting
  • dizziness or lightheadedness
  • slow or irregular heart rate

Your risk of developing lactic acidosis may be higher if you have:

  • sepsis (blood infection)
  • dehydration
  • liver problems
  • kidney problems
  • heart failure
  • alcoholism (alcohol misuse)

X-ray procedure

You’ll need to stop taking this drug for a short time if you plan to have an injection of dye or contrast for an x-ray procedure. This substance can affect how your kidneys work and put you at risk for lactic acidosis.

Stevens-Johnson syndrome

Though rare, this drug can cause serious skin reactions, including Stevens-Johnson syndrome. These conditions can cause raised welts, facial swelling, fever, and trouble breathing. See a doctor right away or call 9-1-1 if you have signs of a skin reaction after taking this drug.

Pancreatitis

Sitagliptin and metformin can cause inflammation of your pancreas (pancreatitis). Symptoms include severe abdominal pain that travels to your back, or vomiting. Your doctor will monitor you for signs of pancreatitis after starting treatment with this drug.

Drug features

This drug is a prescription drug. It’s available as an oral immediate-release tablet and an oral extended-release tablet. An extended-release drug is released into your bloodstream slowly over time.

This drug is available as the name-brand drugs Janumet and Janumet XR. It’s not available as a generic drug.

This is a combination of two drugs in a single form. It is important to know about all the drugs in the combination because they each may have unique traits.

This drug may be used as part of a combination therapy. That means you may need to take it with other drugs.

Why it's used

This drug is used to control high blood sugar levels caused by type 2 diabetes. It’s used along with diet and exercise.

How it works

This drugs, the two drugs in this medication, work together to improve your blood sugar levels.

More Details

How it works

Sitagliptin and metformin, the two drugs in this medication, work together to improve your blood sugar levels.

Sitagliptin belongs to a class of drugs called dipeptidyl peptidase-4 (DPP-4) inhibitors. A class of drugs refers to medications that work similarly. They are often used to treat similar conditions.

Sitagliptin increases the amount of insulin that your body makes. Insulin is a hormone that moves glucose (sugar) from the bloodstream to the cells. This reduces your blood sugar levels.

Metformin belongs to a class of drugs called biguanides. It lowers the amount of glucose in your blood.

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SECTION 2 of 4

metformin-sitagliptin Side Effects

Oral tablet

More Common Side Effects

The more common side effects that occur with sitagliptin/metformin include:

  • diarrhea

  • upper respiratory tract infection

  • headache

  • nausea

  • vomiting

  • stomach pain

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

Call your doctor right away if you have serious side effects. Call 9-1-1 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Allergic reactions. Symptoms can include:

    • skin rash
    • itching
    • hives
    • swelling of your face, lips, or tongue
  • Skin reactions (including Stevens-Johnson syndrome). Symptoms can include:

    • peeling skin
    • raised welts
    • fever
  • Pancreatitis. Symptoms can include:

    • upper abdominal pain that radiates into the back
    • swollen and tender abdomen
    • nausea
    • vomiting
    • fever
    • increased heart rate
    • muscle aches and pain
  • Low blood sugar (hypoglycemia). Symptoms can include:

    • confusion
    • dizziness
    • hunger
    • unusual weakness or tiredness
    • sweating
    • shakiness
    • feeling cold
    • irritability
    • blurred vision
    • fast heart rate
    • loss of consciousness
    • anxiety
  • Severe joint pain

Pharmacist's Advice
Healthline Pharmacist Editorial Team

This drug does not cause drowsiness. However, it may cause a low blood sugar reaction.

If you have a low blood sugar reaction, you need to treat it.

  • For mild hypoglycemia (55–70 mg/dL), treatment is 15–20 grams of glucose (a type of sugar). You need to eat or drink one of the following:
  • 3–4 glucose tablets
  • a tube of glucose gel
  • ½ cup of juice or regular, non-diet soda
  • 1 cup of nonfat or 1% cow’s milk
  • 1 tablespoon of sugar, honey, or corn syrup
  • 8–10 pieces of hard candy, such as lifesavers
  • Test your blood sugar 15 minutes after you treat the low sugar reaction. If your blood sugar is still low, then repeat the above treatment again.
  • Once your blood sugar is back in the normal range, eat a small snack if your next planned meal or snack is more than 1 hour later. 

If you don’t treat low blood sugar, you can have a seizure, pass out, and possibly develop brain damage. Low blood sugar can even be fatal. If you pass out because of a low sugar reaction or cannot swallow, someone will have to give an injection of glucagon to treat the low sugar reaction. You may need to go to the emergency room.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 4

metformin-sitagliptin May Interact with Other Medications

Oral tablet

Sitagliptin/metformin can interact with other medications, herbs, or vitamins you might be taking. That’s why your doctor should manage all of your medications carefully. If you’re curious about how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Alcohol interaction

You should limit how much alcohol you drink while taking this drug. Alcohol can lower or raise your blood sugar levels, and it may also increase your risk of lactic acidosis. Ask your doctor how much alcohol is safe for you to drink while taking this drug.

Medications that might interact with this drug

Acid-reducing drugs
  • ranitidine

Taking this drug with sitagliptin/metformin may increase levels of metformin in your body. This raises your risk of side effects, such as lactic acidosis.

Antibiotics
  • vancomycin
  • trimethoprim

Taking these drugs with sitagliptin/metformin may increase levels of metformin in your body. This raises your risk of side effects, such as lactic acidosis.

Birth control pills

These drugs can increase your blood sugar when taken with sitagliptin/metformin.

Estrogen

This drug can increase your blood sugar when taken with sitagliptin/metformin.

Glaucoma drugs
  • acetazolamide

This medication can cause metabolic acidosis when taken with sitagliptin/metformin.

Heart drugs
  • amiloride
  •  digoxin
  •  procainamide
  •  triamterene

Taking these drugs with sitagliptin/metformin may increase levels of metformin in your body. This raises your risk of side effects, such as lactic acidosis.

  • diltiazem
  • verapamil
  • niacin

These drugs can increase your blood sugar when taken with sitagliptin/metformin.

Malaria drugs
  • quinidine
  • quinine

Taking these drugs with sitagliptin/metformin may increase levels of metformin in your body. This raises your risk of side effects, such as lactic acidosis.

Pain drugs
  • morphine

Taking these drugs with sitagliptin/metformin may increase levels of metformin in your body. This raises your risk of side effects, such as lactic acidosis.

Psychosis and nausea drugs
  • henothiazine antipsychotics, such as:
    • chlorpromazine
    • fluphenazine
    • perphenazine
    • thioridazine
    • trifluoperazine

These drugs can increase your blood sugar when taken with sitagliptin/metformin.

Seizure drugs
  • topiramate
  • zonisamide

These medications can cause metabolic acidosis when taken with sitagliptin/metformin.

  • phenytoin

This drug can increase your blood sugar when taken with sitagliptin/metformin.

Thyroid drugs

These drugs can increase your blood sugar when taken with sitagliptin/metformin.

Tuberculosis drugs
  • isoniazid

This drug can increase your blood sugar when taken with sitagliptin/metformin.

Water pills (diuretics)
  • thiazides

These drugs can increase your blood sugar when taken with sitagliptin/metformin.

Other drugs
  • corticosteroids

These drugs can increase your blood sugar when taken with sitagliptin/metformin.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

People with pancreatitis

You should not take this drug.

People with liver damage or liver disease

Your risk of developing lactic acidosis may be higher.

People with kidney damage or kidney disease

This drug is removed from your body by your kidneys. If you have kidney problems, you may not be able to remove this drug from your body as well as you should. This can lead to high levels of the medication in your body. This can be dangerous and cause lactic acidosis.

Pregnant women

This drug is a pregnancy category B drug. That means two things:

  1. Research in animals has not shown a risk to the fetus when the mother takes the drug.
  2. There aren’t enough studies done in humans to show if the drug poses a risk to the fetus.

Talk to your doctor if you’re pregnant or planning to become pregnant. Animal studies do not always predict the way humans would respond. Therefore, this drug should only be used in pregnancy if clearly needed.

Women who are breast-feeding

This drug may pass into breast milk and cause serious effects in a breast-feeding child.

You and your doctor may need to decide if you’ll take this drug or breast-feed.

For seniors

Your kidneys may not work was well as they once did. This means that your body may not be able to remove this drug as well as it should. Your doctor may start you on a lower dose so that too much of this drug doesn’t build up in your body. Too much of the drug in your body can be toxic.

For children

The safety and effectiveness of this drug hasn’t been established in children younger than 18 years.

When to call the doctor

You should call your doctor if you have signs of low or high blood sugar. If your symptoms are severe, go to the emergency room.

Symptoms of low blood sugar include:

  • sweating
  • chills
  • feeling nervous or anxious
  • headaches
  • dizziness
  • shakiness
  • blurry vision
  • fast heart rate
  • seizures
  • loss of consciousness
  • loss of coordination

Symptoms of high blood sugar include:

  • urinating often
  • feeling very thirsty or hungry
  • fatigue
  • blurry vision
  • slow healing bruises
  • tingling, pain, or numbness in your hands or feet

Allergies

This drug can cause a severe allergic reaction. Symptoms include:

  • trouble breathing
  • swelling of your throat or tongue
  • hives
  • Stevens-Johnson syndrome (peeling skin, raised welts, and fever)

If you have these symptoms, call your doctor right away. If they are severe, call 9-1-1 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it before. Taking it a second time after an allergic reaction could be fatal.

SECTION 4 of 4

How to Take metformin-sitagliptin (Dosage)

Oral tablet

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Type 2 diabetes

Brand: Janumet

Form: Oral immediate-release tablet
Strengths:
  • 50 mg sitagliptin/500 mg metformin
  • 50 mg sitagliptin/1,000 mg metformin

Brand: Janumet XR

Form: Oral extended-release tablet
Strengths: 
  • 100 mg sitagliptin/1,000 mg metformin
  • 50 mg sitagliptin/500 mg metformin
  • 50 mg sitagliptin/1,000 mg metformin
Adult dosage (ages 18–64 years)

Immediate-release tablets:

  • The starting dose is one 50 mg sitagliptin/500 mg metformin tablet. It should be taken by mouth two times per day with meals.
  • Your doctor may slowly increase your dose to 50 mg sitagliptin/1,000 mg metformin taken twice per day.

Extended-release tablets:

  • The starting dose is one 100 mg sitagliptin/1,000 mg metformin tablet taken one time per day with your evening meal.
  • Your doctor may slowly increase your daily dose to 100 mg sitagliptin/2,000 mg metformin.
Child dosage (ages 0–17 years)

This medication hasn’t been studied in children. It shouldn’t be used in people younger than 18 years.

Senior dosage (ages 65 years and older)

Your body processes this drug more slowly. Your doctor may start you on a lower dose so that too much of this drug doesn’t build up in your body. Too much of the drug in your body can be dangerous.

Special considerations

Kidney disease: You shouldn’t use this drug if you have certain serum creatinine levels. These are 1.5 mg/dL and below in males, or 1.4 mg/dL and below in females, or abnormal creatinine clearance.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Healthline Pharmacist Editorial Team

This drug comes with serious risks if you don’t take it as prescribed.

If you stop taking the drug suddenly or don’t take it at all

You may not be able to get your blood sugar down to normal levels. This can lead to problems caused by uncontrolled diabetes. These include nerve damage, heart disease, heart attack, stroke, and damage to your eyes.

If you miss doses or don’t take the drug on schedule

Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much

If you think that you’ve taken too much sitagliptin/metformin, call a Poison Control Center or go to the emergency room right away. Taking too much sitagliptin/metformin can cause severe low blood sugar or lactic acidosis.

Symptoms of low blood sugar include:

  • confusion
  • dizziness
  • hunger
  • unusual weakness or tiredness
  • sweating
  • shakiness
  • feeling cold
  • irritability
  • blurred vision
  • fast heart rate
  • loss of consciousness
  • anxiety

Symptoms of lactic acidosis include:

  • tiredness
  • weakness
  • unusual muscle pain
  • trouble breathing
  • unusual sleepiness
  • stomach pains, nausea, or vomiting
  • dizziness or lightheadedness
  • slow or irregular heart rate

What to do if you miss a dose

If you forget to take your dose, take it as soon as you remember. If it’s just a few hours before the time for your next dose, then only take one dose at that time. Never try to catch up by taking two doses at once. This could cause dangerous side effects.

How to tell if the drug is working

Your blood sugar levels should be lower. Your doctor can test your blood sugar levels, or you can do it at home using a blood sugar meter. Your doctor can tell you more.

This drug is used for long-term treatment.

Take the tablets with meals and a drink of water

This includes both the extended-release tablets and the immediate-release tablets. Don’t skip meals, as this will affect how the drug works in your body.

Don’t cut or crush the tablets

This includes both the extended-release tablets and the immediate-release tablets.

Store this drug carefully

  • Keep this drug at room temperature, between 68°F (20°C) and 77°F (25°C).
  • Don’t freeze this drug.
  • Keep this drug away from light.
  • Keep your drugs away from areas where they could get wet, such as bathrooms. Store this drug away from moisture and damp locations.

Travel

When traveling with your medication:

  • Always carry your medication with you or in your carry-on bag.
  • Don’t worry about airport x-ray machines. They can’t hurt this medication.
  • You may need to show airport staff your pharmacy’s label to clearly identify the medication. Keep the original prescription label with you.
  • Don’t leave this medication in the car, especially when the temperature is hot or freezing.
  • Lancets need to be used to test your blood sugar. If you’re flying, check with the airline for any special rules about traveling with lancets.

Self-management

Your doctor may want you to check your blood glucose levels at home. You can do that using a blood glucose meter.

You’ll need to learn how to do the following:

  • use a blood glucose meter to test your blood sugar regularly at home
  • recognize the signs and symptoms of high and low blood sugar
  • treat high and low blood sugar reactions

While taking this drug you’ll need to test your blood sugar levels. You may need to buy the following:

  • sterile alcohol wipes
  • lancing device and lancets (a needle used to obtain drops of blood from your finger to test your blood sugar)
  • blood sugar test strips
  • blood glucose meter
  • needle container for safe disposal of lancets

Clinical monitoring

Before starting and during your treatment with this drug, your doctor may check your:

  • blood sugar levels
  • glycosylated hemoglobin (A1C) levels. This test measures your blood sugar control over the last 2–3 months.
  • kidney function
  • blood cell counts

Your diet

This drug is used in combination with diet changes and exercise to treat type 2 diabetes. Follow the nutrition plan that your doctor, registered dietitian, or diabetes educator recommends.

Hidden costs

In addition to the medication, you’ll also need the following for blood sugar testing:

  • sterile alcohol wipes
  • lancing device and lancets (a needle used to obtain drops of blood from your finger to test your blood sugar)
  • blood sugar test strips
  • blood glucose meter
  • needle container for safe disposal of lancets

Insurance

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about other drug options that may work for you.

What does the pill look like?

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on September 15, 2015

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 other 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.
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