How It Works
Both components of Janumet XR have distinct mechanisms of action. The sitagliptin component works by protecting incretins, which are hormones your body releases when you eat. Incretins tell the pancreas to produce more insulin and signal the liver to stop making excess sugar. DPP-4 enzymes break down incretins quickly, but sitagliptin inhibits the enzymes to keep the incretins active longer and help keep blood sugar low, especially after meals.
The metformin component works by reducing glucose production and helping your body utilize the insulin it has already produced.
| Quick Facts | |
|---|---|
| Common Brands | Janumet XR |
| Drug Class | Dipeptidyl peptidase-4 (DPP-4) and biguanide |
| Generic Status | No generic version available |
| Availability | Prescription only |
Dosing
Janumet XR is available in multiple dosage options. Common strengths include:
- 50 mg of sitagliptin/500 mg of metformin
- 50 mg of sitagliptin/1000 mg of metformin
- 100 mg of sitagliptin/1000 mg of metformin
Doctors normally prescribe Janumet XR as a once-daily medication. Due to the extended-release mechanism, patients are advised never to split, crush, or chew the tablet — this can lead to too much medication being released into the body at once.
Note: The dosing information below is for educational purposes only. Your prescribing physician will determine your specific dose based on your individual health needs. Always follow your healthcare provider’s instructions for exact dosing.
Uses
FDA-Approved Uses
Janumet XR is FDA-approved to improve blood sugar control in adults with type 2 diabetes mellitus. The drug is intended for use in combination with a healthy diet and regular physical activity.
Off-Label Uses
You may see Janumet XR prescribed for uses that are not “FDA-approved.” This is a very common and legal practice called “off-label” prescribing, where a doctor uses their clinical judgment to prescribe a drug for a different (but well-researched) purpose.
Common off-label uses for Janumet XR currently found in clinical research and practice include:
- Polycystic ovary syndrome (PCOS): Metformin improves insulin sensitivity, so providers may prescribe Janumet XR to help manage the metabolic and hormonal imbalances associated with PCOS.
- Prediabetes: In certain individuals who are considered high-risk for type 2 diabetes, Janumet XR and other metformin-containing products may be used to delay progression of the disease.
Side Effects
Many patients tolerate Janumet XR well, but close medical monitoring is important for gauging how your body responds to both of the medication’s active ingredients.
Common Side Effects
Common side effects from taking Janumet XR include:
- Diarrhea, nausea, gas, and an upset stomach
- Headache
- Stuffy or runny nose, sore throat, and other upper respiratory symptoms
Serious Side Effects
Serious side effects are rare, but it’s important to know what to look for if they do occur. Serious side effects from taking Janumet XR include:
- Lactic acidosis: Metformin has been linked to this rare but life-threatening buildup of lactic acid in the blood. Symptoms include muscle pain, difficulty breathing, fatigue, and coldness in the hands and feet.
- Pancreatitis: DPP-4 inhibitors such as sitagliptin have been associated with pancreatic inflammation. Signs include vomiting and abdominal pain that radiates to the back.
- Kidney function changes: Since metformin is cleared in the kidneys, a sudden decrease in kidney function while taking Janumet XR can be dangerous.
- Heart failure: Some studies suggest sitagliptin can increase the risk of heart failure in patients with existing heart or kidney disease. Patients are advised to contact their provider if they notice sudden weight gain or swelling in the feet and legs.
- Vitamin B12 deficiency: Long-term metformin use can interfere with vitamin B12 absorption, potentially leading to anemia.
Call your doctor immediately if you experience any concerning or prolonged symptoms.
Pharmacist Tips
Take The Dose With Food
Per standard guidelines, patients are advised to take their Janumet XR tablet with food to reduce the risk of side effects such as upset stomach and diarrhea. Taking the tablet with your largest meal of the day is advised to prevent gastrointestinal problems.
Swallow The Tablet Whole
Standard guidelines recommend swallowing the Janumet XR tablet whole to ensure the medication is released over an extended period. Talk to your doctor if you have a hard time swallowing.
Hydration Is Key
Dehydration can increase the risk of lactic acidosis, a potentially life-threatening side effect of Janumet XR. Guidelines recommend contacting your doctor if you experience severe vomiting or diarrhea, as these side effects may warrant pausing the medication.
Remember The Contrast Dye
Janumet XR contains a contrast dye that can show up on X-rays and CT scans. If you have one of these procedures scheduled, the attending physician may request you to stop taking the medication for up to 48 hours.
Monitor Your B12 Levels
Janumet XR and other medications with metformin can lower B12 levels over time. If you feel unusually tired or experience tingling in your hands and feet, your doctor can check your B12 levels.
Drug Interactions
Janumet XR can interact with several other medications and substances, either by affecting kidney clearance or compounding the effects of drugs that already lower blood sugar. Known interactions with Janumet XR include:
- Alcohol: Excessive alcohol consumption significantly increases the risk of lactic acidosis in people who take metformin. Doctors typically recommend limiting alcohol intake while on Janumet XR.
- Insulin and sulfonylureas: While Janumet XR rarely causes hypoglycemia on its own, the risk increases when you take it alongside insulin or medications like glipizide.
- Cimetidine: Cimetidine, a heart medication sold under the brand name Tagamet, can increase metformin levels in the blood and raise the risk of side effects.
- Diuretics and blood pressure medications: Certain water-pill diuretics and ACE inhibitor blood pressure medicines can affect kidney function, which in turn interferes with how your body processes Janumet XR.
Always give your doctor and pharmacist a complete list of all your medications, vitamins, and supplements to check for potential interactions.
FAQs
What is the difference between regular Janumet and extended-release Janumet XR?
Regular Janumet is an immediate-release medication taken twice daily, while Janumet XR is an extended-release medication taken once daily. Patients typically prefer Janumet XR because of its more convenient dosing schedule and lower risk of stomach-related side effects.
Should Janumet XR tablets be taken with a meal or on an empty stomach?
Per standard guidelines, patients are advised to take their Jaumet XR tablet with food to reduce the risk of upset stomach, diarrhea, and other gastrointestinal problems. Food creates a protective barrier around the stomach lining to minimize irritation from the drug’s metformin component.
Is Janumet XR approved to treat type 1 diabetes?
No, Janumet XR does not treat type 1 diabetes and has only been approved to treat type 2 diabetes. People with type 1 diabetes do not produce insulin on their own, so their condition typically requires a different therapeutic approach.
Can taking Janumet XR cause a vitamin B12 deficiency?
Yes, vitamin B12 deficiency is a known side effect of taking Janumet XR and other drugs with metformin. Providers usually recommend monitoring B12 levels with regular blood tests for people who use Janumet XR long-term.
Can Janumet XR cause hypoglycemia if taken without insulin or sulfonylureas?
When patients take Janumet XR on its own, their risk of developing hypoglycemia is low because sitagliptin primarily works when you are eating, during which time blood sugar is rising. The risk of hypoglycemia increases when Janumet XR is taken alongside insulin or sulfonylureas.
Is Janumet XR considered safe for use during pregnancy or while breastfeeding?
Doctors generally do not recommend Janumet XR to pregnant or breastfeeding patients. Providers often advise these patients to switch to insulin during pregnancy to manage their blood sugar. Speak with your doctor to assess the best treatment plan for you if you are planning to become pregnant, pregnant, or breastfeeding.
How long does Janumet XR take to lower hemoglobin A1c levels?
Janumet XR begins working within the first week of treatment to lower daily blood sugar levels. It may take up to 6 months before you see significant changes in A1c levels.
Comparable Medications
Janumet XR, Januvia, Metformin ER, Synjardy XR, or Jentadueto?
Janumet XR is a combination drug primarily used to manage type 2 diabetes as an adjunct to diet and exercise. Other medications are available for type 2 diabetes, and your doctor may recommend an alternative to Janumet XR based on factors like your age and medical history. Janumet XR alternatives include:
Sitagliptin Tablets
From $249.99
Sitagliptin (Januvia) focuses solely on incretin hormone protection and does not contain metformin. Janumet XR contains both sitagliptin and metformin to block liver glucose production and desensitize the body to insulin. Doctors may prescribe Janumet XR to patients with type 2 diabetes after single-drug treatments like Januvia have not been sufficient to control blood sugar.
Metformin ER
From $24.99
This is a widely prescribed extended-release medication for managing type 2 diabetes. It does not contain sitagliptin or any other DPP-4 inhibitor. If metformin ER is not effective on its own in lowering daily blood sugar and A1c levels, your doctor may prescribe Janumet XR, which contains both metformin and sitagliptin.
Synjardy XR
Synjardy XR is a combination drug containing metformin and empagliflozin, an SGLT2 inhibitor that helps the kidneys remove excess sugar from the blood through the urine. The liver and pancreas metabolize sitagliptin in Janumet XR. A doctor may prescribe one of these medications over the other based on a patient's specific medical history.
Jentadueto
Jentadueto is another combination medication for type 2 diabetes that contains linagliptin, not sitagliptin, in addition to metformin. Your body processes linagliptin differently from sitagliptin, so doctors may recommend Jentadueto over Janumet XR for patients with kidney impairment.
We Have Janumet XR in Stock. Get Yours Today!
Important: Information on this page is for educational purposes only. Prescribing decisions are made by independent, licensed providers. TelyRx operates technology-enabled pharmacies and a telehealth platform that connects patients with licensed providers. Prescriptions, when provider-approved and issued, are filled and shipped by TelyRx-affiliated pharmacies. We do not employ physicians or make prescribing decisions. Learn more about our editorial standards here.