Janumet (metformin and sitagliptin)

How does Janumet work?

The two medications used in Janumet (metformin and sitagliptin) work differently to reduce blood sugar levels in patients with type 2 diabetes. Metformin belongs to a drug class called biguanides. It works by decreasing sugar production in the liver and reducing glucose absorption by the intestines. Sitagliptin belongs to the drug class called Dipeptidyl peptidase-4 inhibitors (DPP4 inhibitors). It works by regulating how much insulin your body produces after eating. Together these medications help to control blood sugar levels.

How is it used?

Storage

Janumet should be stored between 68°F to 77°F (20°C to 25°C)

How to Take

Janumet should be taken with meals. Do not crush, chew or break extended-release tablets. The tablets should be swallowed whole.

Dosage

Janumet is available in immediate-release tablets and extended-release tablets.

Immediate-release tablets are available in the following strengths:

• 500mg/50mg
• 1000mg/50mg

Extended-release tablets are available in the following strengths:

• 500mg/50mg
• 1000mg/50mg
• 1000mg/100mg

Dosage for Adults

A dosage of Janumet should be individualized based on the patient’s current regime, effectiveness, and tolerability. The recommended starting dose for patients not currently treated with metformin is Janumet 500mg/50mg twice daily. The dosage can be gradually increased to reduce gastrointestinal side effects associated with metformin. The recommended starting dose for patients already being treated with metformin should add sitagliptin dosed at 50mg twice daily (100mg total daily dose).

Do not exceed 2000mg of metformin and 100mg of sitagliptin daily.

Dosage for Children

Janumet is not indicated in children and should only be used if aged 18 years and older.

Missed Dose

If you miss a dose of Janumet, take it as soon as you remember. If it’s almost time for your next dose, skip the missed dose and return to your regular schedule. Do not take two doses at the same time.

Overdose

If you overdose on Janumet, serious side effects can develop, including severe low blood sugar (hypoglycemia).

Symptoms of low blood sugar include extreme weakness, nausea, tremors, sweating, confusion, trouble speaking, fast heart rate, and seizures.

If you suspect an overdose, seek emergency medical attention or call the poison control helpline at 1-800-222-1222.

Side Effects

If you experience signs and symptoms of an allergic reaction, such as hives, rash, itching, difficulty breathing, or swelling of the face, mouth, or throat, seek medical attention immediately.

The most common side effects of Janumet include:

• Low blood sugar
• Upset stomach/ indigestion
• Nausea, vomiting, and diarrhea
• Headache
• Weakness
• Cold symptoms such as nasal congestion, sneezing, and sore throat

Some severe side effects can also occur; call your doctor if you experience any of the following symptoms

• Itching, blisters, or skin breakdown
• Severe joint pain
• Decreased urination
• Shortness of breath
• Leg and feet swelling
• Rapid weight gain
• Signs of low blood sugar include headaches, sleepiness, dizziness, sweating, feeling jittery, or fast heart rate.

Some people can develop lactic acidosis while taking metformin. If you experience any of the following symptoms, stop taking Janumet and seek immediate medical attention. Lactic acidosis can be fatal.

• Unusual muscle pain
• Feeling cold
• Difficulty breathing
• Feeling dizzy, lightheaded, tired, or weak
• Stomach pain with nausea and vomiting
• Slow, irregular heartbeats

Warnings & Precautions

Janumet is contraindicated in those with a known allergy or sensitivity to metformin or sitagliptin.

Children

Janumet has not been studied or approved in children under 18 years old.

Geriatric Use

Use caution in patients over the age of 65. Elderly patients have a greater risk of developing metformin-associated lactic acidosis due to a greater likelihood of hepatic, renal, or cardiac impairment. Renal function should be assessed intermittently while taking Janumet.

Pregnancy

Do not take Janumet if you are pregnant. No studies have been performed to test the safety in these patients.

Lactation

Do not take Janumet if you are breastfeeding. No studies have been performed to test the safety in these patients.

Type 1 Diabetes

Janumet is not approved for the treatment of type 1 diabetes.

Lactic Acidosis

Lactic acidosis is a metabolic condition that results in a low pH and an elevated lactate level in the blood. An overdose of metformin is known to be a cause of lactic acidosis. Several conditions that can increase the risk of developing lactic acidosis are kidney problems, liver problems, and advanced age. Regular blood work should be performed to monitor liver and kidney function when taking Janumet.

Signs and symptoms of early lactic acidosis can include fatigue, lethargy, muscle pain, and respiratory distress. More advanced symptoms of lactic acidosis include hypotension, hypothermia, heart irregularities, and bradycardia. These patients must be treated in a hospital setting, and Janumet must be discontinued until the patient has stabilized.

Pancreatitis

Reports of pancreatitis have been reported while taking Janumet. Patients should be monitored for signs and symptoms of pancreatitis. If pancreatitis is suspected, Janumet should be discontinued.

Renal Impairment

Janumet should not be used in people with decreased renal function. Patients with a GFR of less than 30 should not use Janumet. GFR should be monitored intermittently while taking Janumet to reduce the risk of developing lactic acidosis.

Hepatic Impairment

The use of Janumet in patients with liver disease should be avoided due to an increased risk of lactic acidosis.

Heart Failure

Heart failure has been reported in patients taking DPP-4 inhibitors. Caution should be used in patients with a history of heart failure. Patients should be monitored for signs and symptoms of heart failure while taking Janumet.

Alcohol Use

Alcohol can increase the risk of lactic acidosis. Excessive alcohol use while taking Janumet is not recommended.

Vitamin B12 Levels

Janumet can decrease vitamin B12 levels in some patients. These patients often do not show any symptoms of vitamin b12 deficiency. Vitamin B12 supplementation is recommended for some patient populations. Levels of vitamin B12 have been known to increase upon discontinuation of Janumet.

Hypoglycemia

Hypoglycemia has been reported in patients taking Janumet. Blood sugar should be monitored while taking this medication.

 Severe Joint Pain

Severe and disabling joint pain has been reported in patients taking DPP-4 inhibitors (sitagliptin). Symptoms can occur at any time while taking Janumet and should resolve quickly after discontinuation of the medication.

Diabetic Ketoacidosis

Janumet is not used in the treatment of diabetic ketoacidosis. Diabetic ketoacidosis is a life-threatening condition characterized by a blood sugar greater than 240mg/dL and the presence of ketones in the blood. Symptoms of DKA include increased thirst and urination, fast deep breathing, fruity-smelling breath, headache, nausea, vomiting, lethargy, and dry mouth. If you are experiencing symptoms of DKA and have a blood sugar greater than 240mg/dL, call 911 or seek immediate medical attention.

Bullous Pemphigoid

Patients taking DPP-4 inhibitors (sitagliptin) have reported the development of bullous pemphigoid, a rare skin condition that causes large, fluid-filled blisters. Patients should be instructed to watch for skin eruptions and seek medical treatment immediately if they occur.

Drug Interactions

This is not a complete list of potential drug interactions. Before taking Janumet, tell your doctor if you take any medications, herbal supplements, or vitamins.

Catatonic Drugs

Catatonic drugs such as amiloride, digoxin, morphine, procainamide, quinidine, quinine, ranitidine, triamterene, trimethoprim, or vancomycin, are eliminated by renal tubular secretion and can compete with metformin for common renal tubular support systems. Careful monitoring is recommended in patients taking Janumet and catatonic drugs together.

Carbonic Anhydrase Inhibitors

Medications such as Topiramate can increase the risk of lactic acidosis. More frequent monitoring is needed in patients who take carbonic anhydrase inhibitors and Janumet.

Drugs that Reduce Metformin Clearance

The use of drugs that interfere with renal tubular transport could increase systemic exposure to metformin and increase the risk of lactic acidosis. The risks vs. benefits should be considered when used together.

IV Contrast

Janumet should not be given to patients who have received IV contrast for at least 48 hours to reduce the risk of renal impairment.

Alternative Medications

There are other drugs available to treat type 2 diabetes. Speak to your doctor to discuss other medications.

Alpha-glucosidase inhibitors

These drugs lower blood sugar by reducing glucose absorption in the small intestine and slowing carbohydrate breakdown

• Precose (acarbose), Glyset (miglitol)

Biguanides

Metformin, one of the medications found in Janumet, is a biguanide. Biguanides work by reducing the amount of glucose produced by the liver and slow carbohydrate breakdown. These medications should not be used together with Janumet but can be used as an alternative.

• Metformin, Glumetza, Riomet

Dopamine agonists

Dopamine agonists are used in the treatment of type 2 diabetes. They work by decreasing the amount of glucose excreted by the liver

• Cyclocet (bromocriptine)

DPP-4 Inhibitors

Sitagliptin, a drug found in Janumet, is a DPP-4 Inhibitor. These medications influence the pancreas to secrete more insulin and decrease the amount of glucose released by the liver. DPP-4 inhibitors should not be used together with Janumet but can be used as an alternative.

• Januvia (sitagliptin), Onglyza (saxagliptin)

Meglitinide

These medications help the pancreas secrete more insulin.

• Prandin (repaglinide), Starlix (nateglinide)

SGLT2 inhibitors

These medications help the kidneys remove extra glucose.

• Invokana (canagliflozin), Jardiance (empagliflozin)

Sulfonylureas

These medications help the pancreas to secrete more insulin

• Glucotrol (glipizide), Amaryl (glimepiride)

Thiazolidinediones

medications allow more glucose to enter fat, muscles, and the liver.

• Actos (pioglitazone), Avandia (rosiglitazone)

Frequently Asked Questions