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
2. 50/1000, which contains 50mg of Januvia and 1000mg of
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
- 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
- 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
- Upper respiratory tract infection
- 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:
Flatulence Body weakness
- Abdominal discomfort
Drug Interactions with Janumet
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.
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.
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
channel blockers like nifedipine can increase the amount of metformin in the
blood. Nifedipine seems to increase the amount of metformin absorbed from a
- 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
- 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 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
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
- 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.
- Light headedness.
- Myalgia or muscle pain.
- 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
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
- 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.
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
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
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