Sitagliptin/metformin (By mouth)


Metformin Hydrochloride (met-FOR-min hye-droe-KLOR-ide), Sitagliptin Phosphate (sit-a-GLIP-tin FOS-fate)

Treats type 2 diabetes. Used together with proper diet and exercise to help control high blood sugar.

Brand Name(s)

Janumet, Janumet XR

There may be other brand names for this medicine.

When This Medicine Should Not Be Used

Do not use this medicine if you have had an allergic reaction to metformin or sitagliptin, or if you have kidney disease, or metabolic acidosis (including diabetic ketoacidosis).

How to Use This Medicine

Tablet, Long Acting Tablet

  • Your doctor will tell you how much of this medicine to use and how often. Your dose may need to be changed several times in order to find out what works best for you. Do not use more medicine or use it more often than your doctor tells you to.
  • It is best to take this medicine with food or milk.
  • Take the extended-release tablets as directed in the evening.
  • Swallow the extended-release tablet whole. Do not crush, break, or chew it.
  • Carefully follow your doctor's instructions about any special diet or exercise program. Test your blood sugar regularly.
  • This medicine should come with a Medication Guide. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions. Ask your pharmacist for the Medication Guide if you do not have one.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you also use insulin or other diabetes medicine that you take by mouth (such as glimepiride, glipizide, glyburide, tolbutamide, Actos®, Amaryl®, Avandia®, Glucotrol®, or Orinase®).
  • Make sure your doctor knows if you are also using acetazolamide (Diamox®), cimetidine (Tagamet®), dichlorphenamide (Daranide®), digoxin (Digitek®, Lanoxin®), isoniazid (Nydrazid®), morphine, niacin (vitamin B3), procainamide (Procanbid®), quinidine (Quinidex®), quinine (Qualaquin®), ranitidine (Zantac®), topiramate (Topamax®), trimethoprim (Proloprim®, Trimpex®), vancomycin (Vancocin®), or zonisamide (Zonegram®).
  • Tell your doctor if you are also using certain blood pressure medicines (such as atenolol, diltiazem, metoprolol, nifedipine, Cardizem®, or Procardia®), a diuretic (water pill, such as amiloride, furosemide, hydrochlorothiazide [HCTZ], triamterene, Dyrenium®, or Lasix®), a phenothiazine medicine (such as prochlorperazine, Compazine®, Mellaril®, Phenergan®, Thorazine®, or Trilafon®), phenytoin (Dilantin®), a steroid medicine (such as prednisone, Medrol®), or a thyroid replacement (such as levothyroxine, liothyronine, Cytomel®, or Synthroid®), estrogen hormones (Premarin®), or birth control pills.
  • Do not drink excessive amounts of alcohol while taking this medicine.

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have kidney problems, liver disease, congestive heart failure, heart disease, adrenal or pituitary problems, anemia, or vitamin B12 deficiency. Make sure your doctor knows if you are injured or sick, especially if you are dehydrated, or you have an infection, severe vomiting, diarrhea, or fever.
  • Do not use this medicine to treat type 1 diabetes.
  • Pancreatitis may occur while you are using this medicine. Stop using this medicine and tell your doctor right away if you have sudden and severe stomach pain, nausea, vomiting, fever, or lightheadedness. Tell your doctor if you drink alcohol or have gallstones, high cholesterol, or high triglycerides, or if you have had pancreas problems before. These conditions may increase your risk for pancreatitis.
  • Make sure any doctor or dentist who treats you knows that you are using this medicine. This medicine may interact with the dye used for an X-ray or CT scan.
  • Rarely, this medicine may cause a serious condition called lactic acidosis. Stop taking this medicine and call your doctor right away if you feel sick, or if you are drowsy, or you have muscle pain, trouble breathing, or an upset stomach. Lactic acidosis could happen if you have kidney or liver problems, a severe infection (sepsis), or hypoxemia (low oxygen levels in your blood) or if you are dehydrated. Tell your doctor if you get sick and have a fever, vomiting, or diarrhea, because these could cause dehydration. Drink plenty of fluids, especially if you exercise or are active in hot weather.
  • Rarely, this medicine may cause kidney problems, sometimes requiring dialysis.
  • You may develop low blood sugar while you are taking this medicine. You may feel weak, drowsy, confused, anxious, or very hungry. You may have trouble seeing or have a headache that won't go away. Tell your doctor if this happens. Low blood sugar may be caused by exercising more than normal or waiting too long to eat.
  • Your doctor will need to check your blood or urine at regular visits while you are using this medicine. Be sure to keep all appointments.You will also need to check your blood sugar regularly at home.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, or red skin rash
  • Bluish lips or skin
  • Change in how much or how often you urinate
  • Extreme weakness, tiredness, or confusion
  • Fast heartbeat, cold sweat
  • Fever, chills, runny or stuffy nose, cough, sore throat, and body aches
  • Increased hunger
  • Lightheadedness, dizziness, or fainting
  • Rapid or troubled breathing, nausea and vomiting
  • Shaking, trembling
  • Sudden and severe stomach pain, nausea, vomiting, fever, lightheadedness

If you notice these less serious side effects, talk with your doctor:

  • Diarrhea, mild stomach pain, or upset stomach
  • Headache

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last Reviewed on 06/12/2013

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission ( URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2013 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.