Generic Name: metformin and sitagliptin (met FOR min and SI ta glip tin)
Brand Name: Janumet, Janumet XR
Medically reviewed by Kaci Durbin, MD. Last updated on May 1, 2020.
What is Janumet?
Janumet contains a combination of metformin and sitagliptin. Metformin and sitagliptin are oral diabetes medicines that help control blood sugar levels.
Metformin works by decreasing glucose (sugar) production in the liver and decreasing absorption of glucose by the intestines. Sitagliptin works by regulating the levels of insulin your body produces after eating.
Janumet is used together with diet and exercise to improve blood sugar control in adults with type 2 diabetes mellitus.
Janumet is not used to treat type 1 diabetes.
You should not use Janumet if you have severe kidney disease or diabetic ketoacidosis (call your doctor for treatment with insulin).
Janumet may cause a serious condition called lactic acidosis. Get emergency medical help if you have even mild symptoms such as: muscle pain or weakness, numb or cold feeling in your arms and legs, trouble breathing, stomach pain, nausea with vomiting, slow or uneven heart rate, dizziness, or feeling very weak or tired.
Janumet may also lead to a serious condition called pancreatitis. Call your doctor right away if you have severe stomach pains with or without vomiting.
Before taking this medicine
You should not use Janumet if you are allergic to metformin or sitagliptin (Januvia), or if you have severe kidney disease.
To make sure Janumet is safe for you, tell your doctor if you have ever had:
kidney disease (your kidney function may need to be checked before you take this medicine);
high triglycerides (a type of fat in the blood);
Some people taking metformin develop a serious condition called lactic acidosis. This may be more likely if you have liver or kidney disease, congestive heart failure, surgery, a heart attack or stroke, a severe infection, if you are 65 or older, if you are dehydrated, or if you drink a lot of alcohol. Talk with your doctor about your risk.
If you need to have surgery or any type of x-ray or CT scan using a dye that is injected into your veins, you may need to temporarily stop taking Janumet. Be sure your caregivers know ahead of time that you are using this medication.
Follow your doctor's instructions about using Janumet if you are pregnant or you become pregnant. Blood sugar control is very important during pregnancy, and your dose needs may be different during each trimester of pregnancy. Having high blood sugar may cause complications in both the mother and the baby.
It may not be safe to breastfeed while using this medicine. Ask your doctor about any risk. Your dose needs may also be different while you are breastfeeding.
Janumet is not approved for use by anyone younger than 18 years old.
How should I take Janumet?
Take Janumet exactly as prescribed by your doctor. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.
Take Janumet with meals.
Do not crush, chew, or break an extended-release tablet. Swallow it whole.
Janumet tablets may not completely dissolve in the body. Part of the tablet may appear in your stool. This is a normal side effect of Janumet and will not make the medicine less effective.
Call your doctor if you see a tablet in your stool several times.
You may have low blood sugar (hypoglycemia) and feel very hungry, dizzy, irritable, confused, anxious, or shaky. To quickly treat hypoglycemia, eat or drink a fast-acting source of sugar (fruit juice, hard candy, crackers, raisins, or non-diet soda).
Your doctor may prescribe a glucagon injection kit in case you have severe hypoglycemia. Be sure your family or close friends know how to give you this injection in an emergency.
Also watch for signs of high blood sugar (hyperglycemia) such as increased thirst or urination, blurred vision, headache, and tiredness.
Blood sugar levels can be affected by stress, illness, surgery, exercise, alcohol use, or skipping meals. Ask your doctor before changing your dose or medication schedule.
Janumet is only part of a complete treatment program that may also include diet, exercise, weight control, regular blood sugar testing, and special medical care. Follow your doctor's instructions very closely.
Store at room temperature away from moisture and heat.
What happens if I miss a dose?
Take the missed dose as soon as you remember (be sure to take the medicine with food). Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. You may have severely low blood sugar (extreme weakness, nausea, tremors, sweating, confusion, trouble speaking, fast heartbeats, or seizure).
What to avoid
Avoid drinking alcohol. It lowers blood sugar and may increase your risk of lactic acidosis.
Janumet side effects
Get emergency medical help if you have signs of an allergic reaction to Janumet: (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).
Stop taking this medicine and call your doctor right away if you have symptoms of pancreatitis: severe pain in your upper stomach spreading to your back, nausea and vomiting, loss of appetite, or fast heartbeats.
Some people develop lactic acidosis while taking metformin. Early symptoms may get worse over time and this condition can be fatal. Stop taking this medicine and get emergency medical help if you have even mild symptoms such as:
unusual muscle pain;
feeling dizzy, light-headed, tired, or very weak;
stomach pain, nausea with vomiting; or
slow or irregular heartbeat.
Call your doctor at once if you have any of these serious side effects:
itching, blisters, breakdown of the outer layer of skin;
severe or ongoing pain in your joints;
little or no urinating; or
shortness of breath (even while lying down), swelling in your legs or feet, rapid weight gain; or
signs of low blood sugar, including headache, sleepiness, dizziness, sweating, feeling jittery, hunger, or fast heartbeat.
Common Janumet side effects may include:
low blood sugar (if you also use insulin or another oral diabetes medication);
upset stomach, gas, diarrhea, nausea, vomiting;
headache, weakness; or
cold symptoms such as runny or stuffy nose, sneezing, sore throat.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect Janumet?
Many drugs can interact with metformin and sitagliptin. Some drugs can affect how well Janumet controls your blood sugar. Other drugs may increase your risk of lactic acidosis.
Tell your doctor if you use any of the following medications before taking Janumet:
anti-seizure medications (including topiramate, zonisamide, acetazolamide, phenytoin, and others)
anti-viral medications for HIV or AIDS;
antipsychotic medications (especially chlorpromazine, prochlorperazine, thioridazine, and others);
antacid medications including cimetidine;
corticosteroid medications (such as prednisone),
estrogen-containing medications including birth control pills or hormone replacement;
heart or blood pressure medications (especially digoxin, diuretics or water pills, calcium channel blockers, and others); or
other diabetes medications including insulin, sulfonylureas, or others
Not all possible interactions are listed in this medication guide. Tell your doctor about all medicines you use, and those you start or stop using. Give a list of all your medicines to any healthcare provider who treats you.
More about Janumet (metformin / sitagliptin)
- Side Effects
- During Pregnancy
- Dosage Information
- Drug Images
- Drug Interactions
- Support Group
- Pricing & Coupons
- En Español
- 58 Reviews
- Drug class: antidiabetic combinations
- FDA Alerts (4)
- FDA Approval History
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Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Janumet only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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