Metformin & Sitagliptin

Sitagliptin/metformin is a prescription medication used to treat type 2 diabetes in adults.

Sitagliptin/metformin 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.

Sitagliptin/metformin is also available as an extended release tablet and is taken once a day with a meal preferably in the evening. Take sitagliptin/metformin extended release tablets whole. Do not break, cut, crush, dissolve, or chew sitagliptin/metformin extended release tablets before swallowing. If you cannot swallow Janumet XR tablets whole, tell your doctor.

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

Sitagliptin/metformin is a prescription medicine that contains two prescription diabetes medicines, sitagliptin and metformin. Sitagliptin/metformin 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.

Metformin & Sitagliptin may be found in some form under the following brand names:

• Janumet

• Janumet XR

Serious side effects have happened in people taking sitagliptin/metformin (see "Drug Precautions"). 

The most common side effects of sitagliptin/metformin include:

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

Taking sitagliptin/metformin 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. Sitagliptin/metformin may have other side effects, including:

• Swelling of the hands or legs.
• Swelling of the hands and legs can happen if you take sitagliptin/metformin in combination with rosiglitazone (Avandia). Rosiglitazone is another type of diabetes medicine.
• Low blood sugar (hypoglycemia). If you take sitagliptin/metformin 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 sitagliptin/metformin. Signs and symptoms of low blood sugar may include: 
• headache
• drowsiness
• weakness
• dizziness
• confusion
• irritability
• hunger
• fast heart beat
• sweating
• feeling jittery

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 sitagliptin/metformin drug interactions. Ask your doctor or pharmacist for more information.

Serious side effects can happen in people taking sitagliptin/metformin, including:

1. Lactic Acidosis. Metformin, one of the medicines in sitagliptin/metformin, 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 sitagliptin/metformin 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 sitagliptin/metformin.
• 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 sitagliptin/metformin, tell your doctor if you have ever had:

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

Stop taking sitagliptin/metformin 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 sitagliptin/metformin 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 sitagliptin/metformin. 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 sitagliptin/metformin 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 sitagliptin/metformin 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 sitagliptin/metformin if you are allergic to any of the ingredients in sitagliptin/metformin. Symptoms of a serious allergic reaction to sitagliptin/metformin 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

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of sitagliptin/metformin there are no specific foods that you must exclude from your diet when receiving this medication.

Before you take sitagliptin/metformin, tell your doctor if you:

• have or have had inflammation of your pancreas (pancreatitis)
• have kidney problems
• have liver problems
• have heart problems, including congestive heart failure
• are older than 80 years. If you are over 80 years old you should not take sitagliptin/metformin unless your kidneys have been checked and they are normal
• drink alcohol very often, or drink a lot of alcohol in short-term “binge” drinking
• you are going to get an injection of dye or contrast agents for an x-ray procedure, sitagliptin/metformin will need to be stopped for a short time. Talk to your doctor about when you should stop sitagliptin/metformin and when you should start sitagliptin/metformin again.
• have any other medical conditions
• are pregnant or breastfeeding

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Sitagliptin/metformin may affect how well other drugs work and some drugs can affect how well sitagliptin/metformin works.

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.

Sitagliptin/metformin 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.

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

It is not known if sitagliptin/metformin 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 sitagliptin/metformin.

Take sitagliptin/metformin exactly as your doctor tells you.

• Your doctor may change your dose of sitagliptin/metformin if needed.
• Your doctor may tell you to take sitagliptin/metformin along with certain other diabetes medicines. Low blood sugar can happen more often when sitagliptin/metformin is taken with certain other diabetes medicines.
• Take sitagliptin/metformin with meals to lower your chance of having an upset stomach.
• Continue to take sitagliptin/metformin as long as your doctor tells you.
• If you take too much sitagliptin/metformin, call your doctor or local Poison Control Center right away.
• If you miss a dose, take it with food as soon as you remember. If you do not remember until it is time for your next dose, skip the missed dose and go back to your regular schedule. Do not take two doses of sitagliptin/metformin at the same time.

Sitagliptin/metformin regular release tablets

• Sitagliptin/metformin regular release tablets are taken twice a day, with meals.

Sitagliptin/metformin extended release tablets

• Sitagliptin/metformin extended release tablets are taken once a day with a meal to help to lower your chance of having an upset stomach. It is better to take sitagliptin/metformin extended release tablets with your evening meal.
• Take sitagliptin/metformin extended release tablets whole. Do not break, cut, crush, dissolve, or chew sitagliptin/metformin extended release tablets before swallowing. If you cannot swallow sitagliptin/metformin extended release tablets whole, tell your doctor.
• You may see something that looks like the sitagliptin/metformin extended release tablet in your stool (bowel movement). If you see tablets in your stool several times, talk to your doctor. Do not stop taking sitagliptin/metformin extended release tablets without talking to your doctor.

You may need to stop taking sitagliptin/metformin for a short time. Call your doctor for instructions if you:

• are dehydrated (have lost too much body fluid). Dehydration can occur if you are sick with severe vomiting, diarrhea or fever, or if you drink a lot less fluid than normal.
• plan to have surgery.
• are going to get an injection of dye or contrast agent for an x-ray procedure.

When your body is under some types of stress, such as fever, trauma (such as a car accident), infection or surgery, the amount of diabetes medicine that you need may change. Tell your doctor right away if you have any of these problems and follow your doctor’s instructions.

• Check your blood sugar as your doctor tells you to.
• Stay on your prescribed diet and exercise program while taking sitagliptin/metformin.
• Talk to your doctor about how to prevent, recognize and manage low blood sugar (hypoglycemia), high blood sugar (hyperglycemia), and problems you have because of your diabetes.
• Your doctor will check your diabetes with regular blood tests, including your blood sugar levels and your hemoglobin A1C.
• Your doctor will do blood tests to check how well your kidneys are working before and during your treatment with sitagliptin/metformin.

Take sitagliptin/metformin 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 sitagliptin/metformin 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.

Sitagliptin/metformin regular release tablets

Sitagliptin/metformin 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 sitagliptin/metformin 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 dose will be increased slowly to reduce gastrointestinal side effects associated with metformin up to the maximum recommended daily dose.
• 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 sitagliptin/metformin is 50 mg sitagliptin/1000 mg metformin hydrochloride twice daily.

Sitagliptin/metformin extended release tablets

Sitagliptin/metformin extended release tablets should generally be given with food to reduce the gastrointestinal side effects associated with the metformin component. Sitagliptin/metformin extended release tablets should generally be given once daily with a meal preferably in the evening.

The starting dose of sitagliptin/metformin extended release tablets should be based on the patient's current regimen.

• In patients not currently treated with metformin, the recommended total daily starting dose of sitagliptin/metformin extended release tablets is 100 mg sitagliptin and 1000 mg metformin hydrochloride (HCl) extended-release. The dose will be increased slowly to reduce gastrointestinal side effects associated with metformin up to the maximum recommended daily dose.
• In patients already treated with metformin, the recommended total daily starting dose of sitagliptin/metformin extended release tablets is 100 mg sitagliptin and the previously prescribed dose of metformin.
• For patients taking metformin immediate-release 850 mg twice daily or 1000 mg twice daily, the recommended starting dose of sitagliptin/metformin extended release tablets is two 50 mg sitagliptin/1000 mg metformin hydrochloride extended-release tablets taken together once daily.
• Maintain the same total daily dose of sitagliptin and metformin when changing between JANUMET (sitagliptin and metformin HCl immediate-release) and JANUMET XR (sitagliptin/metformin extended release tablets). The dose will be increased slowly to reduce gastrointestinal side effects associated with metformin up to the maximum recommended daily dose.

The 100 mg sitagliptin/1000 mg metformin hydrochloride extended-release tablet should be taken as a single tablet once daily. Patients using two JANUMET XR tablets (such as two 50 mg sitagliptin/500 mg metformin hydrochloride extended-release tablets or two 50 mg sitagliptin/1000 mg metformin hydrochloride extended-release tablets) should take the two tablets together once daily.

Patients treated with an insulin secretagogue or insulin

Co-administration of sitagliptin/metformin 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 sitagliptin/metformin in patients previously treated with other oral antihyperglycemic agents and switched to sitagliptin/metformin. Any change in therapy of type 2 diabetes should be undertaken with care and appropriate monitoring as changes in glycemic control can occur.

If you take too much sitagliptin/metformin (more than the prescribed dose), call your local Poison Control Center right away.

• Store sitagliptin/metformin at 68°F to 77°F (20°C to 25°C).
• Keep sitagliptin/metformin and all medicines out of the reach of children.

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.