Medication

Janumet

Generic name: sitagliptin/metformin

Pharmacist-reviewed drug information from the RxWiki encyclopedia.

Overview

Janumet is a prescription medication used to treat type 2 diabetes in adults.

Janumet is a single tablet containing 2 prescription drugs. Sitagliptin belongs to a group of drugs called dipeptidyl peptidase-4 (DPP-4) inhibitors, which help lower blood sugar levels. Metformin belongs to a group of drugs called biguanides, which decrease the amount of sugar made by the liver and help cells to respond to insulin.

This medication comes in tablet form and is taken twice a day, with meals.

Common side effects include stuffy nose, sore throat, nausea, vomiting, and diarrhea.

What is it used for?

Janumet is a prescription medicine that contains two prescription diabetes medicines, sitagliptin and metformin. Janumet can be used along with diet and exercise to lower blood sugar in adults with type 2 diabetes. 

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

How to take it

Take Janumet exactly as prescribed by your doctor. Follow the directions on your prescription label carefully. Your doctor will determine the best dose for you.

The dose of Janumet will be individualized on the basis of the patient's current regimen, effectiveness, and tolerability while not exceeding the maximum recommended daily dose of 100 mg sitagliptin and 2000 mg metformin.

Janumet should generally be given twice daily with meals. The dose will be increased slowly to reduce gastrointestinal side effects associated with metformin.

The starting dose of Janumet should be based on the patient's current regimen.

  • The recommended starting dose in patients not currently treated with metformin is 50 mg sitagliptin/500 mg metformin hydrochloride twice daily.
  • The starting dose in patients already treated with metformin should provide 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.

Patients treated with an insulin secretagogue or insulin

Co-administration of Janumet with an insulin secretagogue (e.g., sulfonylurea) or insulin may require lower doses of the insulin secretagogue or insulin to reduce the risk of hypoglycemia (low blood sugar).

No studies have been performed specifically examining the safety and efficacy of Janumet in patients previously treated with other oral antihyperglycemic agents and switched to Janumet. Any change in therapy of type 2 diabetes should be undertaken with care and appropriate monitoring as changes in glycemic control can occur.

Warnings

WARNING: LACTIC ACIDOSIS

Lactic acidosis is a rare, but serious complication that can occur due to metformin accumulation. The risk increases with conditions such as sepsis, dehydration, excess alcohol intake, hepatic insufficiency, renal impairment, and acute congestive heart failure.

The onset is often subtle, accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, increasing somnolence, and nonspecific abdominal distress.

Laboratory abnormalities include low pH, increased anion gap and elevated blood lactate.

If acidosis is suspected, this medication should be discontinued and the patient hospitalized immediately.

Serious side effects can happen in people taking Janumet, including:

1. Lactic Acidosis. Metformin, one of the medicines in Janumet, can cause a rare but serious condition called lactic acidosis (a build-up of lactic acid in the blood) that can cause death. Lactic acidosis is a medical emergency and must be treated in the hospital.

Stop taking Janumet and call your doctor right away if you get any of the following symptoms, which could be signs of lactic acidosis. Tell your doctor if you:

  • feel very weak or tired
  • have unusual (not normal) muscle pain
  • have trouble breathing
  • have unusual sleepiness or sleep longer than usual
  • have sudden stomach or intestinal problems with nausea and vomiting or diarrhea
  • feel cold, especially in your arms and legs
  • feel dizzy or lightheaded
  • have a slow or irregular heartbeat

You have a higher chance of getting lactic acidosis if you:

  • have kidney problems. People whose kidneys are not working properly should not take Janumet.
  • have liver problems
  • have congestive heart failure that requires treatment with medicines
  • drink alcohol very often, or drink a lot of alcohol in short-term "binge" drinking
  • get dehydrated (lose a large amount of body fluids). This can happen if you are sick with a fever, vomiting, or diarrhea. Dehydration can also happen when you sweat a lot with activity or exercise and do not drink enough fluids.
  • have certain x-ray tests with dyes or contrast agents that are injected into your body
  • have surgery
  • have a heart attack, severe infection, or stroke
  • are 80 years of age or older and have not had your kidneys tested

2. Pancreatitis (inflammation of the pancreas) which may be severe and lead to death.

Certain medical problems make you more likely to get pancreatitis. Before you start taking Janumet, tell your doctor if you have ever had:

  • pancreatitis
  • stones in your gallbladder (gallstones)
  • a history of alcoholism
  • high blood triglyceride levels

Stop taking Janumet and call your doctor right away if you have pain in your stomach area (abdomen) that is severe and will not go away. The pain may be felt going from your abdomen through to your back. The pain may happen with or without vomiting. These may be symptoms of pancreatitis.

3. Low blood sugar (hypoglycemia). If you take Janumet with another medicine that can cause low blood sugar, such as a sulfonylurea or insulin, your risk of getting low blood sugar is higher. The dose of your sulfonylurea medicine or insulin may need to be lowered while you use Janumet. Signs and symptoms of low blood sugar may include:

  • headache
  • drowsiness
  • weakness
  • dizziness
  • confusion
  • irritability
  • hunger
  • fast heart beat
  • sweating
  • feeling jittery

4. Serious allergic reactions. If you have any symptoms of a serious allergic reaction, stop taking Janumet and call your doctor right away. Your doctor may give you a medicine for your allergic reaction and prescribe a different medicine for your diabetes.

5. Kidney problems, sometimes requiring dialysis have occurred with Janumet use.

6. Severe and Persistent Joint Pain. If you experience severe and persistent joint pain, contact your doctor right away. Do not stop taking your medication. Your doctor will decide if your medication is the possible cause of severe  joint pain and will discontinue the drug if appropriate.

Do not take Janumet if you are allergic to any of the ingredients in Janumet. Symptoms of a serious allergic reaction to Janumet may include:

  • rash
  • raised red patches on your skin (hives)
  • swelling of the face, lips, tongue, and throat that may cause difficulty in breathing or swallowing

Side effects

Serious side effects have happened in people taking Janumet (see "Drug Precautions"). 

The most common side effects of Janumet include:

  • stuffy or runny nose and sore throat
  • upper respiratory infection
  • diarrhea
  • nausea and vomiting
  • gas, upset stomach, indigestion
  • weakness
  • headache

Taking Janumet with meals can help lessen the common stomach side effects of metformin that usually happen at the beginning of treatment. If you have unusual or sudden stomach problems, talk with your doctor. Stomach problems that start later during treatment may be a sign of something more serious.

Janumet may have other side effects, including:

  • Swelling of the hands or legs.
  • Swelling of the hands and legs can happen if you take Janumet in combination with rosiglitazone (Avandia). Rosiglitazone is another type of diabetes medicine.
  • Low blood sugar (hypoglycemia) If you take Janumet with another medicine that can cause low blood sugar, such as a sulfonylurea or insulin, your risk of getting low blood sugar is higher. The dose of your sulfonylurea medicine or insulin may need to be lowered while you use Janumet. Signs and symptoms of low blood sugar may include:
  • headache
  • drowsiness
  • weakness
  • dizziness
  • confusion
  • irritability
  • hunger
  • fast heart beat
  • sweating
  • feeling jittery

Drug interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you are taking:

  • amiloride
  • digoxin
  • morphine
  • procainamide
  • quinidine
  • quinine
  • ranitidine
  • triamterene
  • trimethoprim
  • vancomycin
  • other medicines to treat diabetes
  • insulin

This is not a complete list of Janumet drug interactions. Ask your doctor or pharmacist for more information.

Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Janumet falls into category B. There are no well-done studies that have been done in humans with sitagliptin/metformin. No animal studies have been conducted with the combined drugs in this medication. Animal studies performed with sitagliptin or metformin individually did not harm the fetus.

Janumet should be used during pregnancy only if clearly needed as the safety of this medication in pregnant women is not known.

Breastfeeding

It is not known if Janumet crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using Janumet.

 

Quick facts

Metformin & Sitagliptin can cause low blood sugar, especially If you take sitagliptin/metformin with another medicine that can cause low blood sugar. Know the signs and symptoms of low blood sugar.

Take sitagliptin/metformin with meals to lower your chance of having an upset stomach.

Check your blood sugar as your doctor tells you to.

Stay on your prescribed diet and exercise program while taking sitagliptin/metformin.

All information on this site is provided “as-is” for informational purposes only and is not a substitute for medical advice or treatment. You should consult with a medical professional if you have any questions about your health.