8 mins read

Overview: Sitagliptin/metformin helps lower blood sugar levels in people with type 2 diabetes. It works by increasing insulin levels, especially after you eat, and reducing how much sugar you absorb from things you eat and drink. Common side effects are diarrhea and headache. Notify your healthcare provider if you have severe or frequent episodes of low blood sugar.

Uses

What is sitagliptin/metformin used for?

Sitagliptin/metformin is used to help lower blood glucose (sugar) levels in people with type 2 diabetes.

Sitagliptin/metformin may also be used for other conditions as determined by your healthcare provider.

How does sitagliptin/metformin work (mechanism of action)?

Sitagliptin/metformin works in several ways to help keep your blood sugar levels from getting too high. It increases the levels of natural hormones in your body to lower blood sugar by increasing insulin levels, especially after meals. Insulin is a hormone that helps your body use sugar as a source of energy. Sitagliptin/metformin also decreases the amount of sugar your body absorbs from things you eat and drink, reduces the amount of sugar that your liver makes, and helps your body’s own insulin work better. 

How is sitagliptin/metformin supplied (dosage forms)?

Brands and other names

  • Janumet
  • Janumet XR
  • Zituvimet
  • Zituvimet XR

Dosage forms and strengths

  • 50 mg/500 mg, 50 mg/1000 mg oral tablets
  • 50 mg/500 mg, 50 mg/1000 mg, 100 mg/1000 mg extended-release oral tablets

How should I store sitagliptin/metformin?

Sitagliptin/metformin should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. Read and follow any specific storage recommendations that come with your medicine, such as storing in the original bottle or throwing tablets away after a specified amount of time from when the bottle was first opened. Ask your pharmacist if you have any questions about storing your sitagliptin/metformin.

Side Effects

What are the most common side effects of sitagliptin/metformin?

The most common side effects of sitagliptin/metformin are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Diarrhea
  • Infection of the nose or throat, sore throat
  • Headache

There may be other side effects of sitagliptin/metformin that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of sitagliptin/metformin?

While less common, the most serious side effects of sitagliptin/metformin are described below, along with what to do if they happen.

Severe Allergic Reactions. Sitagliptin/metformin may cause allergic reactions, which can be serious. Stop taking sitagliptin/metformin and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Low Blood Sugar (Hypoglycemia). Sitagliptin/metformin can cause low blood sugar (especially if used with other diabetes medicines), which can be serious and may lead to death. The doses of your other diabetes medicines may need to be changed when taken with sitagliptin/metformin. Call your healthcare provider right away if you have any of the following symptoms of hypoglycemia.

  • Headache
  • Crankiness or anxiety
  • Hunger
  • Dizziness or confusion
  • Blurry vision
  • Slurred speech
  • Sweating
  • Feeling jittery or shakiness
  • Fast heartbeat
  • Seizures

Lactic Acidosis. Sitagliptin/metformin may cause lactic acidosis (a buildup of lactic acid in your blood), which can be serious. Stop taking sitagliptin/metformin and get help right away if you have any of the following symptoms of lactic acidosis.

  • General ill feeling
  • Muscle pain
  • Difficulty breathing
  • Drowsiness 
  • Stomach pain 

Inflammation of the Pancreas (Pancreatitis). Sitagliptin/metformin may cause inflammation of the pancreas, which is called pancreatitis. Stop taking sitagliptin/metformin and call your healthcare provider right away if you have symptoms of pancreatitis including vomiting or severe pain in the upper part of your belly that travels to your back.

Heart Failure. Sitagliptin/metformin may increase your risk of heart failure. Tell your healthcare provider right away if you have any of the following symptoms of heart failure.

  • Shortness of breath or trouble breathing, especially while lying down
  • Swelling in your feet, ankles, or legs
  • Unusually fast weight gain
  • Unusual tiredness

Kidney Damage. Kidney damage can happen when taking sitagliptin/metformin. Call your healthcare provider right away if you have any of the following symptoms of kidney damage.

  • Reduced need to pee
  • Swelling in your feet, ankles, or legs
  • Weakness or unusual tiredness
  • Difficulty catching your breath or chest pain/pressure
  • Confusion
  • Nausea
  • Seizures

Vitamin B12 Deficiency. Sitagliptin/metformin may cause you to have low levels of vitamin B12 in your blood (possibly by decreasing the amount of vitamin B12 your body absorbs from things you eat or drink), which may lead to anemia (low levels of red blood cells). Your healthcare provider will likely use lab tests to check your vitamin B12 levels and for anemia. Tell your healthcare provider right away if you have any of the following symptoms of anemia.

  • Unusual weakness or tiredness
  • Cold hands and feet
  • Fast or abnormal heartbeat
  • Pale or yellowish skin
  • Dizziness, lightheadedness, or feeling like you are about to pass out
  • Shortness of breath

Severe Joint Pain. Sitagliptin/metformin may cause joint pain that can be severe. Call your healthcare provider if you have new or increased joint pain while taking this medicine.

Severe Skin Reactions. Sitagliptin/metformin can cause a rare skin reaction called bullous pemphigoid. This reaction may start as an itchy skin rash and large blisters may form on the skin. You may need treatment in a hospital if this reaction happens. Call your healthcare provider right away if you develop a rash or blisters on the skin.

Warnings & Precautions

Who should not use sitagliptin/metformin?

Allergies to Ingredients. People who are allergic to any of the following should not take sitagliptin/metformin.

  • Janumet
  • Janumet XR
  • Zituvimet
  • Zituvimet XR
  • Sitagliptin
  • Metformin
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific sitagliptin/metformin products they stock.

Kidney Problems. Sitagliptin/metformin should not be used if your kidneys are not working as well as they should be. If there is a concern about the health of your kidneys, your healthcare provider may do tests to determine if they are working well enough to take this medicine.

Metabolic Acidosis, Including Diabetic Ketoacidosis. Sitagliptin/metformin should not be used in people with acute or chronic metabolic acidosis (when there is too much acid in your blood). Tell your healthcare provider if you have a history of metabolic acidosis or diabetic ketoacidosis.

What should I know about sitagliptin/metformin before using it?

Do not take sitagliptin/metformin unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share sitagliptin/metformin with other people, even if they have the same condition as you. It may harm them.

Keep sitagliptin/metformin out of the reach of children.

Take sitagliptin/metformin with a meal to help decrease the chance you will have an upset stomach.

Do not crush, cut, or chew sitagliptin/metformin extended-release tablets. They should be swallowed whole.

Sitagliptin/metformin can cause ovulation (release of an egg from your ovary) if you have not gone through menopause, even if you do not have regular periods. This can increase your chance of getting pregnant.

Certain conditions that cause increased stress on your body, like fever, trauma (such as a car accident), infection, or surgery, can change the amount of diabetes medicines you need to take to control your diabetes. Talk to your healthcare provider if you have any of these conditions to decide if your medicine needs to be changed.

Talk to your healthcare provider about how to prevent, recognize, and manage low blood sugar (hypoglycemia), high blood sugar (hyperglycemia), and diabetes-related problems.

People who are 65 years or older can be at greater risk for some side effects from sitagliptin/metformin. Talk to your healthcare provider about your risks if you are in this age group.

What should I tell my healthcare provider before using sitagliptin/metformin?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if sitagliptin/metformin is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Medical Conditions. Tell your healthcare provider if you have any of the following. 

  • Liver problems
  • Heart problems, including congestive heart failure or a heart attack
  • Drink alcohol often or in large amounts
  • Have an upcoming medical test that uses contrast (a special dye), surgery, or other procedure
  • Dehydration 
  • Severe infection
  • Stroke
  • Inflammation of the pancreas (pancreatitis)
  • Gallbladder problems
  • High triglyceride levels
  • Have low vitamin B12 levels
  • Upcoming surgery

Other Medicines and Supplements. Sitagliptin/metformin may interact with other medicines and supplements. Before taking sitagliptin/metformin, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how sitagliptin/metformin could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. If you get pregnant, talk to your healthcare provider about how to control your blood sugar while you are pregnant.

Breastfeeding. It is unknown if sitagliptin/metformin passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should take sitagliptin/metformin while breastfeeding.

Interactions

Does sitagliptin/metformin interact with foods or drinks?

There are no known interactions between sitagliptin/metformin and foods or drinks.

Alcohol can increase the risk of lactic acidosis. See the Side Effects section for more details. It is unknown if drinking alcohol will affect sitagliptin/metformin in other ways, but alcohol may affect blood sugar levels in people with diabetes. This may interfere with the effect of sitagliptin/metformin. It is best to limit the amount of alcohol you drink.

Does sitagliptin/metformin interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking sitagliptin/metformin.

  • A carbonic anhydrase inhibitor, such as zonisamide (Zonegran), acetazolamide (Diamox), topiramate (Topamax, Trokendi XR, Qudexy XR), or methimazole
  • A medicine for diabetes, especially insulin or any medicine that increases your insulin levels
  • Ranolazine (Aspruzyo Sprinkle), which is a medicine used for chest pain
  • Vandetanib (Caprelsa), which is a medicine used for thyroid cancer
  • Dolutegravir (Tivicay), which is a medicine for HIV or AIDS
  • Cimetidine (Tagamet HB), which is a medicine used for heartburn

Many other medicines can increase your blood sugar and can interfere with the effect of sitagliptin/metformin. Talk to your pharmacist or healthcare provider before starting or stopping other medicines while taking sitagliptin/metformin. You may need to monitor your blood sugar levels more closely during these times.

Some other medicines may alter the blood levels of sitagliptin/metformin. Tell your healthcare provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with sitagliptin/metformin. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much sitagliptin/metformin?

If you or someone else has used too much sitagliptin/metformin, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of sitagliptin/metformin?

If you miss a dose, take it (with food) as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses. 

Look up another drug