Brand
name: Metformin
Pronounced: Meth-for-min
Generic name: Metformin hydrochloride
Why is Metformin prescribed?
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.
Metformin 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.
Metformin is sometimes prescribed along with insulin or certain other
oral antidiabetic drugs such as Micronase or Glucotrol. It is also
used alone.
Standard Metformin tablets are taken two or three times daily. An
extended-release form (Metformin XR) is available for once-daily dosing.
Always remember that Metformin 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 Metformin is not an oral
form of insulin and cannot be used in place of insulin.
Metformin side effects
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 Metformin .
If side effects from Metformin occur, they usually happen during
the first few weeks of therapy. Most side effects are minor and will
go away after you've taken Metformin for a while.
* Side effects may include:
Abdominal discomfort, diarrhea, gas, headache, indigestion, nausea,
vomiting, weakness
Why should Metformin not be prescribed?
Metformin 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 Metformin if you need to take medicine for congestive
heart failure.
Do not take Metformin if you have ever had an allergic reaction to
metformin.
Do not take Metformin 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 Metformin
Before you start therapy with Metformin , 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 Metformin , your
doctor will discontinue Metformin . 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 Metformin 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 Metformin . 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 Metformin . 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
Metformin and periodically thereafter. If you develop liver problems,
your doctor may stop treatment with Metformin .
If you are taking Metformin , you should check your blood or urine
periodically for abnormal sugar (glucose) levels. Your doctor will
do annual blood checks to see if Metformin is causing a vitamin B12
deficiency or any other blood problem.
Metformin 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 Metformin 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 Metformin and ask you to take insulin instead.
You should stop taking Metformin 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 Metformin ,
may decrease with time. This may occur because of either a diminished
responsiveness to Metformin or a worsening of the diabetes.
Possible food and drug interactions when taking Metformin
If Metformin meds 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 Metformin with the following:
Amiloride (Moduretic)
Calcium channel blockers (heart medications) such as Calan, Isoptin,
and Procardia
Cimetidine (Tagamet)
Decongestant, airway-opening drugs such as Sudafed and Ventolin
Digoxin (Lanoxin)
Estrogens such as Premarin
Furosemide (Lasix)
Glyburide (Micronase)
Isoniazid (Rifamate), a drug used for tuberculosis
Major tranquilizers such as Thorazine
Morphine
Niacin (Niaspan)
Nifedipine (Adalat, Procardia)
Oral contraceptives
Phenytoin (Dilantin)
Procainamide (Procanbid, Pronestyl)
Quinidine (Quinidex)
Quinine
Ranitidine (Zantac)
Steroids such as prednisone (Deltasone)
Thyroid hormones such as Synthroid
Triamterene (Dyazide, Dyrenium)
Trimethoprim (Bactrim, Septra)
Vancomycin (Vancocin)
Water pills (diuretics) such as HydroDIURIL, Dyazide, and Moduretic
Do not drink too much alcohol, since excessive alcohol consumption
can cause low blood sugar and alcohol enhances some effects of Metformin .
Special information if you are pregnant or breastfeeding
If you are pregnant or plan to become pregnant, tell your doctor immediately.
Metformin 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 Metformin appears in human breast milk. Therefore,
women should discuss with their doctors whether to discontinue Metformin
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 Metformin
Your doctor will tailor your dosage to your individual needs.
ADULTS
Overdosage
An overdose of Metformin can cause lactic acidosis (see "Most
important fact about Metformin "). If you suspect a Metformin
overdose, seek emergency treatment immediately.
Most important fact about Metformin
Metformin 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 Metformin ?
Do not take more or less of Metformin 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 Metformin 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 Metformin /Metformin
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 Metformin
Store it at room temperature.
