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Janumet/Janumet XR (sitagliptin + metformin, antidiabetic agents)

Uses|Precautions & warnings|Side effects|Interactions|Dosage

Janumet and Janumet XR are brand names of the combination of two drugs, sitagliptin and metformin. Both sitagliptin and metformin are antihyperglycemic or antidiabetic agents, which help control blood sugar levels. This drug is useful for type 2 diabetes patients in combination with diet and exercise.



What is Janumet used for?

Janumet is commonly used for helping lower blood sugar in adults with type 2 diabetes by:

  • Improving insulin sensitivity or response
  • Promoting insulin production
  • Decreasing glucagon production and hepatic glucose production

Important limitations of use:

  • It should not be used in patients with type 1 diabetes or for the treatment of diabetic ketoacidosis.
  • Janumet has not been studied in patients with a history of pancreatitis.

How should I take Janumet?

  • Take Janumet with meals to lower your chance of having an upset stomach.
  • Swallow Janumet tablets whole. Do not break or cut tablets before swallowing.
  • Ask your health care provider any questions you may have about how to use

How do I store Janumet?

Janumet is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store it in the bathroom or the freezer. There may be different brands of this drug that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush this product down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Janumet?

Consult with your doctor or pharmacist, if you are/have:

  • Pregnant or breastfeeding.
  • Taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • An allergy to any of active or inactive ingredients of Janumet or other medications.
  • Any other illnesses, disorders, or medical conditions.
  • Going to get an injection of dye or contrast agents for an X-ray procedure. You will need to temporarily stop taking Janumet.

Is it safe during pregnancy or breastfeeding?

There isn’t enough information about the safety of using this medication during pregnancy and breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this medication.

Side effects

What side effects can occur from Janumet?

Janumet may cause these side effects, such as:

  • Mild symptoms of lactic acidosis, including muscle pain or weakness, numb or cold feeling in your arms and legs, trouble breathing, stomach pain, nausea with vomiting, slow or irregular heart rate, dizziness, or feeling very weak or tired.
  • Signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
  • Pancreatitis – severe pain in your upper stomach spreading to your back, nausea and vomiting, loss of appetite, fast heart rate.
  • Urinating less than usual or not at all.
  • Feeling short of breath (even with mild exertion) swelling or rapid weight gain.
  • Severe skin reaction, fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Not everyone experiences these side effects. In addition, there may be other side effects not listed above. If you have any concerns about a side effect, please consult your doctor or pharmacist.


What drugs may interact with Janumet?

Janumet may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

These medications may affect Sitagliptin and Metformin:

  • Acetazolamide (Diamox);
  • Cimetidine (Tagamet), ranitidine (Zantac);
  • Morphine (MS Contin, Kadian, Oramorph);
  • Ranitidine (Zantac);
  • Topiramate (Topamax);
  • Trimethoprim (Proloprim, Primsol, Bactrim, Cotrim, Septra) or vancomycin (Vancocin, Lyphocin);
  • Glipizide (Glucotrol, Metaglip), glimepiride (Amaryl, Avandaryl, Duetact), glyburide (DiaBeta, Micronase, Glucovance);
  • Heart or blood pressure medications such as amiloride (Midamor), digoxin (Lanoxin), furosemide (Lasix), nifedipine (Nifedical, Procardia), procainamide (Procan, Pronestyl, Procanbid), quinidine (Quin-G), triamterene (Dyrenium).

If you have problems with high blood sugar, taking Janumet® with other drugs could affect your condition, such as:

  • Isoniazid;
  • Diuretics (water pills);
  • Steroids (prednisone and others);
  • Heart or blood pressure medication (Cartia, Cardizem, Covera, Isoptin, Verelan, and others);
  • Niacin (Advicor, Niaspan, Niacor, Simcor, Slo-Niacin, and others);
  • Phenothiazines (Compazine and others);
  • Thyroid medicine (Synthroid and others);
  • Birth control pills and other hormones;
  • Seizure medicines (Dilantin and others);
  • Diet pills or medicines to treat asthma, colds or allergies.

Does food or alcohol interact with Janumet?

Janumet may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. It is best to avoid excessive alcohol intake, as it can affect insulin sensitivity and blood sugar control. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Janumet?

Janumet may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:


The information provided is not a substitute for any medical advice. Therefore, you should always consult with your doctor or pharmacist before using any medication.

What is the dose for an adult?

Individualize the starting dose of Janumet based on the patient’s current regimen. May adjust the dosing based on effectiveness and tolerability while not exceeding the maximum recommended daily dose of 100 mg sitagliptin and 2000 mg metformin.

The recommended starting dose in patients not currently treated with metformin:

50 mg sitagliptin/500 mg metformin hydrochloride twice daily, with gradual dose escalation recommended to reduce gastrointestinal side effects associated with metformin.

The starting dose in patients already treated with metformin:

Sitagliptin dosed as 50 mg twice daily (100 mg total daily dose) and the dose of metformin already being taken.

For patients taking metformin 850 mg twice daily, the recommended starting dose of Janumet is 50 mg sitagliptin/1000 mg metformin hydrochloride twice daily.

What is the dose for a child?

The dosage has not been established in pediatric patients (younger than 18 years old). It may be unsafe for your child. It is always important to fully understand the safety of the drug before using. Please consult with your doctor or pharmacist for more information.

How is Janumet available?

Janumet is available in the following dosage forms and strengths:

  • Film-coated tablets 50mg sitagliptin/500mg metformin (Janumet)
  • Film-coated tablets 50mg sitagliptin/1000mg metformin (Janumet XR)

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to the nearest emergency room.

What should I do if I miss a dose?

If you miss a dose, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.


Janumet. http://www.Janumetxr.com/sitagliptin_metformin_HCL/Janumetxr/consumer/what-is-Janumet/index.xhtml. Accessed October 07, 2016.

Janumet. http://www.merck.com/product/usa/pi_circulars/j/Janumet/Janumet_pi.pdf. Accessed October 07, 2016.

Janumet. https://www.medicines.org.uk/emc/medicine/23111. Accessed October 07, 2016.

Janumet® (Sitagliptin, Metformin). http://www.fda.gov/downloads/drugs/drugsafety/ucm204268.pdf. Accessed October 07, 2016.

Hello Health Group does not provide medical advice, diagnosis or treatment.


Janumet https://www.mims.com/philippines/drug/info/janumet Accessed May 31, 2021

Janumet XR https://www.mims.com/philippines/drug/info/janumet%20xr Accessed May 31, 2021

Janumet Prescribing Information https://www.merck.com/product/usa/pi_circulars/j/janumet/janumet_pi.pdf Accessed May 31, 2021

Janumet XR Prescribing Information https://www.merck.com/product/usa/pi_circulars/j/janumet_xr/janumet_xr_pi.pdf Accessed May 31, 2021

Metformin (Oral Route) https://www.mayoclinic.org/drugs-supplements/metformin-oral-route/description/drg-20067074 Accessed May 31, 2021

Sitagliptin https://www.nhs.uk/medicines/sitagliptin/ Accessed May 31, 2021

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Written by Stephanie Nicole Nera, RPh, PharmD Updated May 31