Janumet is a combination medicine that contains Januvia and metformin. This combination medication was initially approved by the FDA in 2007. Januvia is the trade name for sitagliptin and metformin is the generic name for Glucophage. Metformin and sitagliptin can be safely used together without adverse drug interactions between the two.

How to Use

This diabetes medication is used to treat type 2 diabetes in adults older than18 years of age. It is used in addition to diabetic diet and exercise. It comes in two dosage strength tablets:

1. 50/500, which contains 50mg of Januvia and 500mg of metformin.

2. 50/1000, which contains 50mg of Januvia and 1000mg of metformin.

It is important to know that Januvia 50/500 will deliver the same amount of medication as 50mg of Januvia and 500mg of metformin taken at the same time. In the same manner, the 50/1000 tablet will deliver the same amount of medication as Januvia 50mg and metformin 1000mg taken at this time. This is important because if you are on this diabetic medicine and find out that it is cheaper for you to obtain the medications individually, or if you take Januvia and metformin and find it more convenient to take them in one pill, you should talk to your doctor about switching to the cheaper or more convenient form as you wish. Sometimes, Januvia is introduced when metformin, in combination with diabetic diet and exercise no longer controls the blood sugar adequately. Metformin makes the body more sensitive to insulin, while Januvia raises the amount of insulin available in the blood after a meal. Take this combination medicine twice a day, using the dose that can be bearably and effectively taken by the person to the maximum total dose of 100mg of sitagliptin and 2000mg of metformin. Dose increase should be gradual, to reduce stomach irritation by metformin.

  • Only a doctor or other prescribing clinician can prescribe this diabetic medicine. ·
  • If a person is taking 500mg of metformin twice a day when they start this combination medicine, or if the patient had never been on metformin prior to the introduction of this diabetes medication, the dose should be 50/500 twice a day.
  • If the person needed 1000mg of metformin, before starting on this drug, then he/she should take Janumet 50/1000 twice a day.
  • The dose should be increased gradually until the effective dose is achieved. Patients who are already receiving 850mg of metformin should be given Janumet 50/1000 twice a day.
  • Kidney function should be tested and found to be good before introduction of this diabetic medicine.
  • People on this diabetes medication should avoid excessive alcohol intake in order not to increase the risk for lactic acidosis and pancreatitis.
  • People with infection, trauma or undergoing surgery may need to use insulin to control their diabetes as these conditions can decrease the effectiveness of this medicine.
  • When it is used in combination with insulin or other medications that cause release of insulin, the dose of those medications or insulin should be decreased to decrease the risk of hypoglycemia due to too much insulin.

Janumet Side Effects

  • Diarrhea
  • Upper respiratory tract infection
  • Headache
  • Hypoglycemia (especially when used in combination with sulfonylurea or insulin.)

The above side effects are less than those when metformin is initially introduced. This may be because many people are already stabilized on metformin before being introduced to the combination medicine.

The following side effects of metformin may also be present, especially if the patient was not already taking metformin prior to the introduction of this combination diabetic medication:

  • Nausea/Vomiting
  • Flatulence Body weakness
  • Indigestion
  • Abdominal discomfort

Drug Interactions with Janumet

  • Cationic drugs, which are eliminated by the kidney, like digoxin, morphine, quinidine, ranitidine, trimethoprim, quinine, vancomycin and others can interact with metformin in janumet and thus increase the metformin levels in the blood. This is because these drugs compete for elimination at the kidney and as such, more of each is left in the blood.
  • Patients on digoxin should be observed closely to prevent digoxin toxicity.
  • When this combination diabetic medicine is given in combination with insulin, sulfonylurea or any other drugs that release insulin into the body, the doses of those other drugs should be lowered to avoid hypoglycemia.
  • Furosemide and other diuretics can increase the amount of metformin in the blood. Care should be taken in dosing metformin in patients who are also taking these diuretics.
  • Calcium channel blockers like nifedipine can increase the amount of metformin in the blood. Nifedipine seems to increase the amount of metformin absorbed from a given dose.
  • Steroids like prednisone and other medications that raise blood sugar, seem to reduce the effect of Janumet because of the increase in blood sugar that occurs.

Janumet Adverse Reactions

  • Lactic acidosis can result from metformin content.
  • Kidney failure.
  • Acute pancreatitis due to Januvia.
  • Allergic reactions to sitagliptin include swelling of the skin called angioedema, peeling of the skin, including Stevens-Johnson syndrome; and even anaphylaxis. If any of these occur, Janumet should be stopped immediately.
  • Metformin may decrease the vitamin B12 levels in body. If a person taking this diabetes medication is suspected of having megaloblastic anemia, which is a rare adverse effect of metformin, they should be checked for vitamin B12 deficiency.

Lactic Acidosis

Lactic acidosis is a life-threatening condition that occurs due to buildup metformin and lactic acid in the body. The things that can increase the chance of someone on metformin developing lactic acidosis are:

  • Dehydration – dehydration can result in the increase of metformin in the blood fluid and also decrease the amount of metformin being removed from the blood by the kidney. This can result in the buildup of metformin and lactic acid in the body.
  • Infection – Infection can alter many body functions and result in lactic acid build up.
  • Too much alcohol- alcohol increases the buildup of lactate in the body and can prevent the liver from clearing it up quickly.
  • Kidney damage- This may reduce the rate at which the kidney clears metformin from the blood and as such result in the buildup of metformin and lactic acid in the blood.
  • Liver damage- This can result in lactate that form from metformin not being cleared up quickly from the body, resulting in the buildup of lactic acid in the body.
  • Congestive heart failure – This reduces the force with which the heart pumps blood and as such reduces the ability of the blood to send fluid and metformin to the kidney for clearance. As such, the metformin and lactic acid remain in the blood and can result in lactic acidosis

Signs and Symptoms of Lactic Acidosis are:

  • Trouble breathing.
  • Stomach ache.
  • Nausea.
  • Vomiting.
  • Light headedness.
  • Malaise.
  • Myalgia or muscle pain.
  • Weakness.
  • Hypotension.
  • Chills with decreased temperature.
  • Increased levels of lactate in blood.
  • Low pH because of increase in acid level.

If you are on Janumet and start to experience the above symptoms of lactic acidosis without another known cause, you need to stop taking this medication and inform your doctor immediately. Lactic acidosis is emergency medical situation and the patient needs to be taken to an emergency room and treated in the hospital. Most of the time hemodialysis is used to remove the excess metformin from the blood in order to resolve lactic acidosis. The hemodialysis can also lower the level of the Januvia component of Janumet.

Contraindications for Janumet

The following are people who should not take this combination diabetes medication:

  • People with type 1 diabetes.
  • Those in diabetic ketoacidosis.
  • Those in lactic acidosis.
  • Those with a history of pancreatitis.
  • People who are allergic to either metformin or sitagliptin.
  • People who are having tests that require radiologic contrast materials should stop taking this drug about two days prior to the test and have it reintroduced after the contrast material has been removed from their system. This is because metformin can accumulate in the body in the presence of radiological contrast because both are removed by the kidney. They compete for removal at the level of the kidney.
  • People with liver disease. Though it is the kidney that removes most of the metformin, it is the liver that removes the lactate that forms in the presence of metformin.
  • Pregnant and nursing mothers should not take this combination medicine.
  • Children under below18 years of age should also not take this medication because its safety in this population has not been adequately studied.

Precautions - Januvia Health Tips

  • Lactic acidosis may result from metformin content of the drug when metformin and lactic acid accumulate. Steps should be taken to lower the risk of lactic acidosis, by avoiding excessive alcohol intake. Check kidney and liver functions regularly. If you experience symptoms of lactic acidosis, discontinue this drug immediately and see medical attention.
  • Pancreatitis can result due to Januvia. Observe patients on Janumet for signs and symptoms of pancreatitis. If pancreatitis occurs, discontinue Janumet right away and seek medical intervention.
  • Liver function should be checked regularly. If there is evidence of damage to the liver, Janumet should not be used because it will not be able to clear lactate adequately and that can result in lactic acidosis.
  • Check kidney function regularly, at least once or twice a year because both metformin and Januvia are removed by the kidney. If kidney function is less than desirable, both drugs accumulate. This can result in lactic acidosis or cause further damage to the kidney.
  • Check the levels of vitamin B12 periodically because metformin can result in lowered vitamin B12 levels in some patients. If this happens, the patient may need vitamin B12 supplementation.
  • Be cautious with alcohol intake. Patients should avoid excessive alcohol intake because alcohol increases the amount of lactate formed in the presence of metformin, thus increasing the chance for lactic acidosis. In addition, excessive intake of alcohol is known to cause pancreatitis, so this may increase the incidence of pancreatitis in the presence of sitagliptin.
  • People undergoing surgical procedures, especially those who have to abstain from food should have Janumet withheld until they have resumed regular food and fluid intake after surgery. This will help avoid the risk of lactic acidosis that can result from dehydration and risk of hypoglycemia that can result from sitagliptin.
  • During illness like infection, trauma or surgery, Janumet may lose its ability to control blood sugar. In such instances, insulin may be administered as an alternative means of blood sugar control until the underlying condition is resolved.
  • Conditions that reduce the oxygen in the blood. These conditions reduce the amount of oxygen the blood delivers to tissues and/or increase the presence of waste chemical in blood. These can happen when there conditions like shock, heart attack or heart failure. These conditions predispose the patient to lactic acidosis, and as such, Janumet should be stopped in those instances.
  • Use carefully with sulfonylurea, insulin or any medication that lowers blood sugar in order to prevent hypoglycemia.
  • Iodine contrast materials used for radiological studies are known to slow the removal of metformin by the kidney. This is because the contrast materials also have to be removed by the kidney. As such, metformin accumulate in the body when these contrast materials are in use. Metformin should, therefore, be stopped about two days before such studies that use radiological contrast. Metformin can be restarted when the radiological material has been completely removed from the body.
  • Other drugs that are removed by the kidney called cationic drugs, like digoxin, can make the metformin remain and accumulate in the body and increase the chance of lactic acidosis.
  • Serious allergic reactions may occur due to Januvia component. These reactions include, swelling of the skin, peeling of the skin called Stevens-Johnson syndrome and even anaphylaxis. If any allergic reaction is noticed, the use of Janumet should be stopped immediately.
  • Do not use in children less than 18 years of age as this drug has not been studied in that population.
  • Elderly patients, especially those 80 years or older should not be started on this drug unless their physician determines that their kidney and liver functions are good. Even when those functions are good, the patients should be given the lowest effective dose.

Janumet Overdose

Overdose results when someone takes more than the maximum safe dose of each medication. The doses in which adverse effects could be observed may be when the sitagliptin dose is

greater than 400mg and when the metformin dose is greater than several grams.

Overdose of sitagliptin could result in hypoglycemia and some changes in the QT interval on EKG. Overdose of metformin can result in hypoglycemia in few instances, but places the patient at a great risk for lactic acidosis. Patient who overdoses in Janumet should be taken to the hospital. The usual treatment is the removal of the medication from the stomach, and hemodialysis to remove the medication in the blood. Further doses of the medication are withheld until the overdose is resolved.

Lab Tests for Patients on Janumet

Kidney function should be checked one or two times a year. HbA1C should be checked periodically to monitor the effectiveness of the drug. The level of Vitamin B12 should also be checked periodically and if low, patient may be given vitamin B12 supplement.


Return from Janumet to Diabetes Medications

Be the first to get new health tips by subscribing to our Diabetes Health Tips