Janumet (Metformin and Sitagliptin) - Oral

Warning:

Too much Metformin can cause lactic acidosis (a dangerous build-up of lactic acid in the blood). Some conditions, including sepsis, dehydration, excessive alcohol intake, kidney and liver disorder, and acute heart failure, can increase the risk.


Get emergency medical help if you have symptoms like tiredness (malaise), muscle pain (myalgia), trouble breathing (respiratory distress), abdominal distress, increased somnolence (drowsiness), and lab findings like increased pH, anion gap, and blood lactate.


If you have any of these signs or symptoms, stop using Janumet and talk with your healthcare provider.

What Is Janumet?

Janumet is a combination of the anti-diabetes medicines, metformin and sitagliptin. Metformin and sitagliptin, along with diet and exercise, help improve blood sugar control in type 2 diabetes mellitus.

Metformin is a biguanide, a medicine that decreases glucose (sugar) production in the liver and decreases its absorption by the intestines. Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor. It works by regulating the amounts of insulin to control your blood sugar after you eat. Janumet isn’t used for type 1 diabetes mellitus.

Janumet is a prescription medicine available as a tablet to take by mouth.

Drug Facts

Generic Name: Metformin and Sitagliptin 

Brand Name(s): Janumet, Janumet XR

Drug Availability: Prescription

Therapeutic Classification: Antidiabetic combination

Available Generically: No

Controlled Substance: N/A

Administration Route: Oral 

Active Ingredient: Metformin and Sitagliptin

Dosage Form(s): Tablets

What Is Janumet Used For?

Janumet is used with changes in lifestyle and eating pattern (what you eat) to help control blood sugar levels in type 2 diabetes. This combination medicine has been effective in people whose blood sugar levels are not controlled while using metformin or sitagliptin alone.

It's not recommended to use Janumet in type 1 diabetes mellitus or diabetic ketoacidosis because it would not be effective.

How to Take Janumet

Follow the directions on your prescription label. Ask your healthcare provider or pharmacist for help if there are directions that you don't understand. 

Janumet comes as a tablet to take by mouth. While Janumet is usually taken twice a day with food, Janumet XR is taken once daily with food. Take Janumet precisely as prescribed by your healthcare provider. Do not take this medicine for more, less, or longer than recommended. The dose may be increased gradually to help minimize any gastrointestinal (stomach or intestinal) side effects.

Do not crush, chew, or break Janumet if you’re taking an extended-release tablet. Swallow the whole tablet. These tablets may not completely dissolve in your body, and some tablet parts may pass in your stool. It’s a common side effect of Janumet XR and doesn’t make the tablet less effective. 

Janumet does not cure diabetes. It controls the level of insulin in your body so that you don't experience high blood sugar levels or its symptoms. Don't stop taking your medicine without consulting your healthcare provider, even if you feel well.

Janumet (Metformin and Sitagliptin) Drug Information- A shirtless person showing the pancreas and liver

Verywell / Dennis Madamba

Storage

Store Janumet at room temperature away from light and moisture. Do not store medications in the bathroom. Keep medications away from the sight and reach of children and pets - preferably locked.

Do not throw away expired or unwanted medicines by flushing them down the toilet, pouring them into a drain, or throwing them into the trash. Properly discard your medicines when they have expired or are no longer needed. Consult your pharmacist or your local waste disposal company about discarding your drugs safely.

How Long Does Janumet Take to Work?

Janumet may take a few weeks to improve your blood sugar levels.

What Are the Side Effects of Janumet?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the Food and Drug Administration (FDA) at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Janumet may cause some common side effects such as:

  • Diarrhea
  • Headache
  • Low blood sugar
  • Nausea
  • Upset stomach
  • Stuffy or runny nose
  • Sore throat

Severe Side Effects

Janumet may have some severe side effects such as:

  • Skin reactions, such as itching, blisters, breakdown of the outer layer of skin, fever, sore throat, burning in the eyes, skin pain, red or purple skin rashes, blistering, and peeling
  • Severe or ongoing pain in the joints
  • Little or no urination
  • Shortness of breath (even while lying down)
  • Swelling in the legs or feet
  • Rapid weight gain
  • Signs of hypoglycemia (low blood sugar), like headache, sleepiness, dizziness, sweating, feeling jittery, hunger

Stop taking Janumet and call your healthcare provider if you have symptoms of lactic acidosis, such as:

  • Severe pain in the upper stomach extending to your back
  • Loss of appetite
  • Nausea and vomiting
  • Fast heartbeat

Seek emergency medical help if you have signs of an allergic reaction, such as hives, difficulty breathing, or swelling in your face or throat.

Long-Term Side Effects

Janumet may cause lactic acidosis, a dangerous build-up of lactic acid in the blood. Symptoms may get worse and this condition can be fatal. Ask your healthcare provider about your risk.

Report Side Effects

Janumet may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Janumet Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For type 2 diabetes:
    • For oral dosage form (extended-release tablets):
      • For patients taking metformin alone:
        • Adults—At first, 100 milligrams (mg) of sitagliptin, plus the dose of metformin already being taken once a day. Your doctor may gradually increase your dose until your blood sugar is controlled. If you are taking 850 or 1000 mg of immediate-release metformin 2 times per day, you may start with two 50 mg sitagliptin tablets and 1000 mg of metformin taken together once a day.
        • Children—Use and dose must be determined by your doctor.
      • For patients taking sitagliptin alone:
        • Adults—At first, 100 milligrams (mg) of sitagliptin and 1000 mg of metformin once a day. Your doctor may gradually increase your dose until your blood sugar is controlled. However, the dose is usually not more than 100 mg of sitagliptin and 2000 mg of metformin once a day.
        • Children—Use and dose must be determined by your doctor.
      • For patients using Janumet® immediate-release tablets:
        • Adults—The dose is the same as the dose you are already taking. Your doctor may gradually increase your dose until your blood sugar is controlled. However, the dose is usually not more than 100 mg of sitagliptin and 2000 mg of metformin once a day.
        • Children—Use and dose must be determined by your doctor.
    • For oral dosage form (immediate-release tablets):
      • For patients taking metformin alone:
        • Adults—At first, 50 milligrams (mg) of sitagliptin, plus the dose of metformin already being taken, 2 times per day. Your doctor may gradually increase your dose until your blood sugar is controlled. If you are taking 850 mg of metformin 2 times per day, you may start with 50 mg of sitagliptin and 1000 mg of metformin 2 times per day.
        • Children—Use and dose must be determined by your doctor.
      • For patients taking sitagliptin alone:
        • Adults—At first, 50 milligrams (mg) of sitagliptin and 500 mg of metformin two times per day. Your doctor may gradually increase your dose until your blood sugar is controlled. However, the dose is usually not more than 50 mg of sitagliptin and 1000 mg of metformin two times per day.
        • Children—Use and dose must be determined by your doctor.
      • For patients using metformin and sitagliptin together as separate tablets:
        • Adults—The dose is the same as the dose you are already taking. Your doctor may gradually increase your dose until your blood sugar is controlled.
        • Children—Use and dose must be determined by your doctor.

Modifications

The following modifications (changes) should be kept in mind when using Janumet:

Adults over the age of 65 years: Due to the way kidney function changes in some people over the age of 65 years, careful monitoring is needed when using Janumet in this population.

Breastfeeding: Janumet is excreted in breastmilk. Talk with your healthcare provider if you use Janumet and decide how best to feed your baby.

Missed Dose

If you miss a dose of Janumet, take it as soon as you remember (take Janumet with food). Skip the missed dose if it’s almost time for your next dose. Do not take a double dose to make up for the missed one, which could increase your risk of side effects.

Overdose: What Happens If I Take Too Much Janumet?

Janumet overdose may cause severe low blood sugar with the following symptoms:

  • Confusion
  • Extreme weakness
  • Fast heartbeats
  • Nausea
  • Sweating
  • Seizure
  • Tremors
  • Trouble speaking

What Happens If I Overdose on Janumet?

If you think you or someone else may have overdosed on Janumet, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Janumet, call 911 immediately.

Precautions

Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress at regular visits, especially during the first few weeks that you take this medicine. Blood and urine tests may be needed to check for unwanted effects.

Under certain conditions, too much metformin can cause lactic acidosis. The symptoms of lactic acidosis are severe and appear quickly. It usually occurs when other serious health problems are present, such as a heart attack or kidney failure. Symptoms of lactic acidosis include: abdominal or stomach discomfort, decreased appetite, diarrhea, fast, shallow breathing, a general feeling of discomfort, muscle pain or cramping, and unusual sleepiness, tiredness, or weakness. If you have more than one of these symptoms together, you should get emergency medical help right away.

This medicine may cause hypoglycemia (low blood sugar). This is more common when this medicine is taken together with certain medicines. Low blood sugar must be treated before it causes you to pass out (unconsciousness). People feel different symptoms of low blood sugar. It is important that you learn which symptoms you usually have so you can treat it quickly. Talk to your doctor about the best way to treat low blood sugar.

Hyperglycemia (high blood sugar) may occur if you do not take enough or skip a dose of your medicine, overeat or do not follow your meal plan, have a fever or infection, or do not exercise as much as usual. High blood sugar can be very serious and must be treated right away. It is important that you learn which symptoms you have in order to treat it quickly. Talk to your doctor about the best way to treat high blood sugar.

There may be a time when you need emergency help for a problem caused by your diabetes. You need to be prepared for these emergencies. It is a good idea to wear a medical identification (ID) bracelet or neck chain at all times. Also, carry an ID card in your wallet or purse that says you have diabetes and a list of all your medicines.

Pancreatitis may occur while you are using this medicine. Check with your doctor right away if you have a sudden and severe stomach pain, chills, constipation, nausea, vomiting, loss of appetite, fever, or lightheadedness.

Check with your doctor right away if you have more than one of these symptoms: chest pain, decreased urine output, dilated neck veins, extreme fatigue, irregular breathing, irregular heartbeat, shortness of breath, swelling of the face, fingers, feet, or lower legs, tightness in the chest, trouble breathing, or weight gain. These may be signs of heart failure.

This medicine may cause serious allergic reactions, including anaphylaxis, angioedema, or certain skin conditions (Stevens-Johnson syndrome). These reactions can be life-threatening and require immediate medical attention. Call your doctor right away if you have a rash, itching, blistering, peeling, or loosening of the skin, fever or chills, trouble breathing or swallowing, or any swelling of your hands, face, mouth, or throat while you are using this medicine.

This medicine may cause severe and disabling joint pain. Call your doctor right away if you have severe joint pain while using this medicine.

This medicine may cause bullous pemphigoid. Tell your doctor if you have large, hard skin blisters while using this medicine.

Let your doctor or dentist know that you are taking this medicine. Your doctor may advise you to temporarily stop taking this medicine before you have major surgery or diagnostic tests, including procedures that use contrast dye.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Janumet?

 Janumet is contraindicated in the following conditions:

  • A history of hypersensitivity reactions, like anaphylaxis and angioedema (swelling under your skin), to Janumet, sitagliptin, or any other ingredient in the tablet.
  • Acute or chronic metabolic acidosis (too much acid in your body), such as diabetic ketoacidosis (too many ketones in your blood) with or without coma.
  • Lactic acidosis
  • Kidney disorders
  • Administration of contrast materials (e.g., for CTs and MRIs)

What Other Medications Interact With Janumet?

Use of carbonic anhydrase inhibitors with Janumet increases lactic acidosis risk. More frequent monitoring of people who use this combination is recommended. Carbonic anhydrase inhibitors include:

  • Topamax (topiramate)
  • Zonegran (zonisamide)
  • Diamox (acetazolamide)
  • Keveyis (dichlorphenamide)

When taken with Janumet, some drugs reduce metformin clearance and may increase the risk for lactic acidosis. These include:

  • Ranexa (ranolazine)
  • Caprelsa (vandetanib)
  • Tagamet (cimetidine)

Taking Janumet with an insulin secretagogue (medicine to increase insulin in the body), such as sulfonylureas or insulin, increases your risk of hypoglycemia (low blood sugar levels). You may need to change your dose of insulin secretagogue or insulin. Be sure to mention any other anti-diabetes drugs that you might take, such as:

  • Amaryl (glimepiride)
  • Glucotrol (glipizide)
  • Diabeta (glyburide)

You may need to change your dose to prevent severe hypoglycemia (low blood sugar).

Certain drugs tend to produce hyperglycemia (high blood sugar levels). Close monitoring is required when used with Janumet. These include:

  • Thiazides and other diuretics
  • Corticosteroids
  • Phenothiazines
  • Thyroid products
  • Estrogens
  • Oral contraceptives
  • Phenytoin
  • Nicotinic acid
  • Sympathomimetics
  • Calcium channel blockers (high dosage)
  • Isoniazid

Alcohol can lower your blood sugar levels and also increase your risk of lactic acidosis (dangerous build-up of lactic acid in the blood) when taking Janumet. It’s recommended to limit your alcohol intake when taking Janumet. 

This may not be a complete list of drugs. Tell your healthcare provider about all other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you take to avoid any side effects.

What Medications Are Similar?

There are other drugs available that treat type 2 diabetes. Your healthcare provider may prescribe a monotherapy (single medicine) or a combination drug. 

Examples of other drugs that treat type 2 diabetes include:

  • Januvia (sitagliptin)
  • Onglyza (saxagliptin)
  • Tradjenta (linagliptin)
  • Diabeta (glyburide)
  • Glucotrol (glipizide) 
  • Amaryl (glimepiride)
  • Biguanides, such as metformin (Fortamet, Glumetza, Glucophage, Riomet)

Combination drugs that treat type 2 diabetes, such as:

  • Jentadueto (linagliptin/metformin)
  • Xigduo (dapagliflozin/metformin)
  • Invokamet (canagliflozin/metformin)

Frequently Asked Questions

  • What is Janumet used for?

    Janumet is used along with a healthier eating pattern and exercise to control high blood sugar levels in people living with type 2 diabetes. It does not control blood sugar levels in type 1 diabetes.

  • How does Janumet work?

    Janumet is a combination of two anti-diabetes medicines, sitagliptin and metformin. It controls high blood sugar levels. Both these drugs belong to different classes of drugs. Metformin works by decreasing glucose (sugar) production in your liver and absorption in your intestines. Sitagliptin works by regulating insulin levels in your body produced after eating.

  • Can I drink alcohol while taking Janumet?

    Avoid drinking alcohol while taking Janumet. It can lower your blood sugar levels to a dangerous level (hypoglycemia) and may increase your risk of lactic acidosis (dangerous build-up of lactic acid in your blood).

How Can I Stay Healthy While Taking Janumet?

Janumet is a safe and well-tolerated combination of sitagliptin and metformin drugs. It’s usually used when a single medicine is not working well by itself. Janumet helps decrease your blood sugar. It is a part of a complete treatment program that includes other significant lifestyle changes, such as healthier eating patterns, exercise, weight control, blood sugar monitoring, and medical care.

Follow your healthcare provider's instructions. Always keep a close eye on blood sugar levels. If you have symptoms, such as extreme hunger, dizziness, confusion, or anxiety, you may have low blood glucose (sugar) levels. A glucagon injection kit may help in an emergency. It's important for you and any people close to you to know how to use it. Consult your healthcare provider about it. Keep regular laboratory appointments and follow-ups with your healthcare provider to avoid any severe side effects of Janumet, such as pancreatitis (inflammation of your pancreas) or lactic acidosis (dangerous build-up of lactic acid in the blood). 

Generally, working with a team that includes a registered dietitian nutritionist (RD or RDN) - and particularly one that's a Certified Diabetes Care and Education Specialist (CDCES) - can help you explore your eating, movement, medication habits, and more. RDs can help you build your toolkit and your capacity to avoid spikes in your blood sugar and to help you feel good. Managing blood sugar can be challenging at times and you don't have to do it alone.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. St Onge EL, Miller S, Clements E. Sitagliptin/metformin (Janumet) as combination therapy in the treatment of type-2 diabetes mellitus. P T. 2012;37(12):699-708.

  2. Sanchez-Rangel E, Inzucchi SE. Metformin: clinical use in type 2 diabetes. Diabetologia. 2017;60(9):1586-1593. doi:10.1007/s00125-017-4336-x

  3. Dhillon S. Sitagliptin: a review of its use in the management of type 2 diabetes mellitus. Drugs. 2010;70(4):489-512. doi:10.2165/11203790-000000000-00000

  4. St Onge EL, Miller S, Clements E. Sitagliptin/metformin (Janumet) as combination therapy in the treatment of type-2 diabetes mellitus. P T. 2012;37(12):699-708.

  5. Food and Drug Administration. Janumet label.