Generic name: Metformin hydrochloride
Why is Glucophage prescribed
Glucophage / Metformin is an oral antidiabetic
medication used to treat type 2 (non-insulin-dependent)
diabetes. Diabetes develops when the body proves
unable to burn sugar and the unused sugar builds
up in the bloodstream. Glucophage lowers the
amount of sugar in your blood by decreasing sugar
production and absorption and helping your body
respond better to its own insulin, which promotes
the burning of sugar. It does not, however, increase
the body's production of insulin.
Glucophage is sometimes prescribed along with
insulin or certain other oral antidiabetic drugs
such as glyburide or glipizide. It is also used
alone.
Standard Glucophage tablets are taken two or three
times daily. An extended-release form (Glucophage
XR) is available for once-daily dosing.
Always remember that Glucophage is an aid to,
not a substitute for, good diet and exercise. Failure
to follow a sound diet and exercise plan can lead
to serious complications such as dangerously high
or low blood sugar levels. Remember, too, that
Glucophage is not an oral form of insulin and cannot
be used in place of insulin.
Most important fact about Glucophage
Glucophage could cause a very rare—but
potentially fatal—side effect known as
lactic acidosis. It is caused by a buildup of
lactic acid in the blood. The problem is most
likely to occur in people whose liver or kidneys
are not working well, and in those who have multiple
medical problems, take several medications, or
have congestive heart failure. The risk also
is higher if you are an older adult or drink
alcohol. Lactic acidosis is a medical emergency
that must be treated in a hospital. Notify your
doctor immediately if you experience any of the
following:
- Symptoms of lactic acidosis may include:
Dizziness, extreme weakness or tiredness, light-headedness,
low body temperature, rapid breathing or
trouble breathing, sleepiness, slow or irregular
heartbeat, unexpected or unusual stomach
discomfort, unusual muscle pain
How should you take Glucophage?
Do not take more or less of this medication
than directed by your doctor. The drug should
be taken with food to reduce the possibility
of nausea or diarrhea, especially during the
first few weeks of therapy.
If taking Glucophage XR, be sure to swallow the
tablet whole; do not crush it or chew it. The inactive
ingredients in the tablet may occasionally appear
in the stool. This is not a cause for concern.
- If you miss a dose...
Take it as soon as you remember. If it is almost
time for your next dose, skip the one you
missed and go back to your regular schedule.
Never take 2 doses at the same time.
- Storage instructions...
Store it at room temperature.
What side effects may occur?
Side effects cannot be anticipated. If any develop
or change in intensity, tell your doctor as soon
as possible. Only your doctor can determine if
it is safe for you to continue taking Glucophage.
If side effects from Glucophage occur, they usually
happen during the first few weeks of therapy. Most
side effects are minor and will go away after you've
taken Glucophage for a while.
- Side effects may include:
Abdominal discomfort, diarrhea, gas, headache,
indigestion, nausea, vomiting, weakness
Why should Glucophage not be prescribed?
Glucophage is processed primarily by the kidneys,
and can build up to excessive levels in the body
if the kidneys aren't working properly. It should
be avoided if you have kidney disease or your
kidney function has been impaired by a condition
such as shock, blood poisoning, or a heart attack.
You should not use Glucophage if you need to take
medicine for congestive heart failure.
Do not take Glucophage if you have ever had an
allergic reaction to metformin.
Do not take Glucophage if you have metabolic or
diabetic ketoacidosis (a life-threatening medical
emergency caused by insufficient insulin and marked
by excessive thirst, nausea, fatigue, pain below
the breastbone, and fruity breath). Diabetic ketoacidosis
should be treated with insulin.
Special warnings about Glucophage
Before you start therapy with Glucophage, and
at least once a year thereafter, your doctor
will do a complete assessment of your kidney
function. If you develop kidney problems while
on Glucophage, your doctor will discontinue this
medication. If you are an older person, you will
need to have your kidney function monitored more
frequently, and your doctor may want to start
you at a lower dosage.
You should not take Glucophage for 2 days before
and after having an X-ray procedure (such as an
angiogram) that uses an injectable dye. Also, if
you are going to have surgery, except minor surgery,
you should stop taking Glucophage. Once you have
resumed normal food and fluid intake, your doctor
will tell you when you can start drug therapy again.
Avoid drinking too much alcohol while taking Glucophage.
Heavy drinking increases the danger of lactic acidosis
and can also trigger an attack of low blood sugar.
Because poor liver function could increase the
risk of lactic acidosis, your doctor may decide
to check your liver function before prescribing
Glucophage and periodically thereafter. If you
develop liver problems, your doctor may stop treatment
with Glucophage.
If you are taking Glucophage, you should check
your blood or urine periodically for abnormal sugar
(glucose) levels. Your doctor will do annual blood
checks to see if Glucophage is causing a vitamin
B12 deficiency or any other blood problem.
Glucophage does not usually cause hypoglycemia
(low blood sugar). However, it remains a possibility,
especially in older, weak, and undernourished people
and those with kidney, liver, adrenal, or pituitary
gland problems. The risk of low blood sugar increases
when Glucophage is combined with other diabetes
medications. The risk is also boosted by missed
meals, alcohol, and excessive exercise. To avoid
low blood sugar, you should closely follow the
diet and exercise plan suggested by your doctor.
If your blood sugar becomes unstable due to the
stress of a fever, injury, infection, or surgery,
your doctor may temporarily take you off Glucophage
and ask you to take insulin instead.
You should stop taking Glucophage if you become
seriously dehydrated, since this increases the
likelihood of developing lactic acidosis. Tell
your doctor if you lose a significant amount of
fluid due to vomiting, diarrhea, fever, or some
other condition.
The effectiveness of any oral antidiabetic, including
Glucophage, may decrease with time. This may occur
because of either a diminished responsiveness to
the medication or a worsening of the diabetes.
Possible food and drug interactions when taking
Glucophage
If Glucophage is taken with certain other drugs,
the effects of either could be increased, decreased,
or altered. It is especially important to check
with your doctor before combining Glucophage
with the following:
Amiloride Calcium channel blockers (heart medications)
such as nifedipine and verapamil Cimetidine Decongestant,
airway-opening drugs such as albuterol and pseudoephedrine
Digoxin Estrogens Furosemide Glyburide Isoniazid,
a drug used for tuberculosis Major tranquilizers
such as chlorpromazine Morphine Niacin Nifedipine
Oral contraceptives Phenytoin Procainamide Quinidine
Quinine Ranitidine Steroids such as prednisone Thyroid
hormones such as levothyroxine Triamterene Trimethoprim
Vancomycin Water pills (diuretics) such as hydrochlorothiazide
Do not drink too much alcohol, since excessive
alcohol consumption can cause low blood sugar and
alcohol enhances some effects of this drug.
Special information if you are pregnant or
breastfeeding
If you are pregnant or plan to become pregnant,
tell your doctor immediately. Glucophage should
not be taken during pregnancy. Since studies
suggest the importance of maintaining normal
blood sugar (glucose) levels during pregnancy,
your doctor may prescribe insulin injections
instead.
It is not known whether Glucophage appears in
human breast milk. Therefore, women should discuss
with their doctors whether to discontinue the medication
or to stop breastfeeding. If the medication is
discontinued and if diet alone does not control
glucose levels, then your doctor may consider insulin
injections.
Recommended dosage for Glucophage
Your doctor will tailor your dosage to your
individual needs.
ADULTS
Glucophage
The usual starting dose is one 500-milligram tablet
twice a day, taken with morning and evening meals.
Your doctor may increase your daily dose by 500
milligrams at weekly intervals, based on your response
up to a total of 2,000 milligrams.
An alternative starting dose is one 850-milligram
tablet a day, taken with the morning meal. Your
doctor may increase this by 850 milligrams at 14-day
intervals, to a maximum of 2,550 milligrams a day.
The usual maintenance dose ranges from 1,500 to
2,550 milligrams daily. If you take more than 2,000
milligrams a day, your doctor may recommend that
the medication be divided into three doses, taken
with each meal.
Glucophage XR
The usual starting dose is one 500-milligram tablet
once daily with the evening meal. Your doctor may
increase your dose by 500 milligrams at weekly
intervals, up to a maximum dosage of 2,000 milligrams
a day. If a single 2,000-milligram dose fails to
control your blood sugar, you may be asked to take
1,000-milligram doses twice a day. If you need
more than 2,000 milligrams a day, the doctor will
switch you to regular Glucophage.
CHILDREN
Glucophage
For children 10 to 16 years old, the usual starting
dose is one 500-milligram tablet twice a day with
meals. The dosage may be increased by 500 milligrams
at weekly intervals up to a maximum of 2,000 milligrams
daily. Glucophage has not been tested in children
younger than 10.
Glucophage XR
This form of the drug has not been tested in children
younger than 17.
OLDER ADULTS
Older people and those who are malnourished or
in a weakened state are generally given lower doses
of Glucophage because their kidneys may be weaker,
making side effects more likely.
Overdosage
An overdose of Glucophage can cause lactic acidosis
(see "Most important fact about this drug").
If you suspect a Glucophage overdose, seek emergency
treatment immediately.
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