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Janumet XR Side Effects

Generic Name: metformin / sitagliptin

Note: This page contains information about the side effects of metformin / sitagliptin. Some of the dosage forms included on this document may not apply to the brand name Janumet XR.

Not all side effects for Janumet XR may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to metformin / sitagliptin: oral tablet, oral tablet extended release

In addition to its needed effects, some unwanted effects may be caused by metformin / sitagliptin. In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking metformin / sitagliptin:

Less common
  • Anxiety
  • blurred vision
  • chills
  • cold sweats
  • confusion
  • cool, pale skin
  • depression
  • dizziness
  • fast heartbeat
  • headache
  • increased hunger
  • loss of consciousness
  • mental cloudiness
  • nausea
  • nightmares
  • not thinking clearly
  • seizures
  • shakiness
  • slurred speech
  • unusual tiredness or weakness
  • Abdominal or stomach discomfort
  • decreased appetite
  • diarrhea
  • fast, shallow breathing
  • general feeling of discomfort
  • muscle pain or cramping
  • shortness of breath
  • sleepiness

Some of the side effects that can occur with metformin / sitagliptin may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Bloated
  • excess air or gas in the stomach or intestines
  • fever
  • full feeling
  • indigestion
  • lack or loss of strength
  • muscle aches
  • passing gas
  • sore throat
  • stuffy or runny nose
  • vomiting

For Healthcare Professionals

Applies to metformin / sitagliptin: oral tablet, oral tablet extended release


Very common (10% or more): Hypoglycemia (13.8% when combined with sulfonylurea; 10.9% when combined with insulin)
Common (1% to 10%): Hypoglycemia, decrease levels of vitamin B12 without clinical manifestations and rarely associated with anemia
Rare (less than 0.1%): Lactic acidosis due to metformin

Uncommon (0.1% to 1%): Hypoglycemia

Common (1% to 10%): Hypoglycemia (5% or more when combined with glyburide)
Uncommon (0.1% to 1%): Hypoglycemia
Very rare (less than 0.01%): Lactic acidosis, vitamin B12 deficiency[Ref]

In metformin-treated patients, the incidence of lactic acidosis has been about 1.5 cases per 10,000 patient years. The risk of lactic acidosis has been particularly high in patients with underlying renal insufficiency and rarely in patients with normal renal function. Concomitant cardiovascular or liver disease, sepsis, and hypoxia have also increased the risk of lactic acidosis.

Signs and symptoms of severe acidosis may include vomiting, abdominal pain, nausea, dyspnea, hypothermia, hypotension, and bradycardia.

Long-term treatment with metformin has been associated with a decrease in vitamin B12 absorption. Malabsorption of vitamin B12, due to intrinsic factor deficiency and possibly other mechanisms, in as many as 30% of treated patients, were reported. Megaloblastic anemia has occurred. Decreased levels of vitamin B12 appear to be reversible with discontinuation of metformin or vitamin B12 supplementation.[Ref]


Common (1% to 10%): Diarrhea, nausea, flatulence, vomiting
Uncommon (0.1% to 1%): Constipation, upper abdominal pain, dry mouth
Postmarketing reports: Indigestion, abdominal discomfort, dyspepsia, abdominal pain, acute pancreatitis (including fatal and non-fatal hemorrhagic and necrotizing pancreatitis)

Very common (10% or more): Nausea, vomiting, diarrhea, abdominal pain, loss of appetite

Rare (less than 0.1%): Pancreatitis[Ref]

Nervous system

Common (1% to 10%): Headache
Uncommon (0.1% to 1%): Somnolence
Frequency not reported: Asthenia

Common (1% to 10%): metallic taste[Ref]


Common (1% to 10%): Upper respiratory tract infections, nasopharyngitis, pharyngolaryngeal pain, bronchitis, sinusitis, influenza
Postmarketing reports: Interstitial lung disease[Ref]


Frequency not reported: Hypersensitivity reactions including anaphylaxis[Ref]


Postmarketing reports: Hepatic enzyme elevation

Very rare (less than 0.01%): Liver function disorders, hepatitis


Frequency not reported: Impaired renal function, acute renal failure (sometimes requiring dialysis)


Between October 2006 and December 2013, thirty-three cases of severe arthralgia have been reported to the FDA Adverse Event Reporting System Database. Each case involved the use of 1 or more dipeptidyl peptidase-4 (DPP-4) inhibitor. In all cases, substantial reduction in prior activity level was reported, 10 patients were hospitalized due to disabling joint pain. In 22 cases, symptoms appeared within 1 month of starting therapy, in 23 cases symptoms resolved less than 1 month after discontinuation. A positive rechallenge was reported in 8 cases, with 6 cases involving use of a different DPP-4 inhibitor. Sitagliptin had the greatest number of cases reported (n=28) followed by saxagliptin (n=5), linagliptin (n=2), alogliptin (n=1), and vildagliptin (n=2).[Ref]

Common (1% to 10%): Arthralgia
Postmarketing reports: Myalgia, pain in extremities, back pain[Ref]


Common (1% to 10%): Peripheral edema


Postmarketing reports: Angioedema, rash, urticaria, pruritus, cutaneous vasculitis, exfoliative skin conditions including Steven-Johnson syndrome

Very rare (less than 0.01%): Urticaria, erythema, pruritus


Rare (less than 0.1%): Megaloblastic anemia[Ref]

Decreased serum vitamin B12 levels, without clinical manifestations (rarely megaloblastic anemia), has been reported in approximately 7% of patients. The reduction in vitamin B12 levels may be due to interference with B12 absorption from the B12-intrinsic factor complex and appears to be rapidly reversible with discontinuation of metformin or vitamin B12 supplementation.[Ref]


1. "Product Information. Janumet (metformin-sitagliptin)." Merck & Company Inc, West Point, PA.

2. US Food and Drug Administration "FDA Drug Safety Communication: FDA warns that DPP-4 inhibitors for type 2 diabetes may cause severe joint pain. Available from: URL:" ([2015, Aug 28]):

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