|Drug Name:||Metformin Hydrochloride|
|Manufacturer:||Watson Laboratories, Inc.|
METFORMIN HYDROCHLORIDE TABLETSRead this information carefully before you start taking this medicine and each time you refill your prescription.
There may be new information.
This information does not take the place of your doctor’s advice.
Ask your doctor or pharmacist if you do not understand some of this information or if you want to know more about this medicine.What is metformin?Metformin is used to treat type 2 diabetes.
This is also known as non-insulin-dependent diabetes mellitus.
People with type 2 diabetes are not able to make enough insulin or respond normally to the insulin their bodies make.
When this happens, sugar (glucose) builds up in the blood.
This can lead to serious medical problems including kidney damage, amputations, and blindness.
Diabetes is also closely linked to heart disease.
The main goal of treating diabetes is to lower your blood sugar to a normal level.High blood sugar can be lowered by diet and exercise, by a number of medicines taken by mouth, and by insulin shots.
Before you take metformin, try to control your diabetes by exercise and weight loss.
While you take your diabetes medicine, continue to exercise and follow the diet advised for your diabetes.
No matter what your recommended diabetes management plan is, studies have shown that maintaining good blood sugar control can prevent or delay complications of diabetes, such as blindness.Metformin helps control your blood sugar in a number of ways.
These include helping your body respond better to the insulin it makes naturally, decreasing the amount of sugar your liver makes, and decreasing the amount of sugar your intestines absorb.
Metformin does not cause your body to make more insulin.
Because of this, when taken alone, it rarely causes hypoglycemia (low blood sugar), and usually does not cause weight gain.
However, when it is taken with a sulfonylurea or with insulin, hypoglycemia is more likely to occur, as is weight gain.WARNING: A small number of people who have taken metformin have developed a serious condition called lactic acidosis.
Lactic acidosis is caused by a buildup of lactic acid in the blood.
This happens more often in people with kidney problems.
Most people with kidney problems should not take metformin.
(See “What are the side effects of metformin?”)Who should not take metformin?Some conditions increase your chance of getting lactic acidosis, or cause other problems if you take metformin.
Most of the conditions listed below can increase your chance of getting lactic acidosis.Do not take metformin if you:have kidney problemshave liver problemshave heart failure that is treated with medicines, such as Lanoxin® (digoxin) or Lasix® (furosemide)drink a lot of alcohol.
This means you binge drink for short periods or drink all the timeare seriously dehydrated (have lost a lot of water from your body)are going to have an x-ray procedure with injection of dyes (contrast agents)are going to have surgerydevelop a serious condition, such as heart attack, severe infection, or a strokeare 80 years or older and you have NOT had your kidney function testedTell your doctor if you are pregnant or plan to become pregnant.
Metformin may not be right for you.
Talk with your doctor about your choices.
You should also discuss your choices with your doctor if you are nursing a child.Can metformin hydrochloride tablets be used in children?Metformin has been shown to effectively lower glucose levels in children (ages 10 to 16 years) with type 2 diabetes.
Metformin has not been studied in children younger than 10 years old.
Metformin hydrochloride tablets have not been studied in combination with other oral glucose-control medicines or insulin in children.
If you have any questions about the use of metformin hydrochloride tablets in children, talk with your doctor or other healthcare provider.How should I take metformin hydrochloride tablets?Your doctor will tell you how much medicine to take and when to take it.
You will probably start out with a low dose of the medicine.
Your doctor may slowly increase your dose until your blood sugar is better controlled.
You should take metformin with meals.Your doctor may have you take other medicines along with metformin to control your blood sugar.
These medicines may include insulin shots.
Taking metformin with insulin may help you better control your blood sugar while reducing the insulin dose.Continue your exercise and diet program and test your blood sugar regularly while taking metformin.
Your doctor will monitor your diabetes and may perform blood tests on you from time to time to make sure your kidneys and your liver are functioning normally.
There is no evidence that metformin causes harm to the liver or kidneys.Tell your doctor if you:have an illness that causes severe vomiting, diarrhea or fever, or if you drink a much lower amount of liquid than normal.
These conditions can lead to severe dehydration (loss of water in your body).
You may need to stop taking metformin for a short time.plan to have surgery or an x-ray procedure with injection of dye (contrast agent).
You may need to stop taking metformin hydrochloride tablets for a short time.start to take other medicines or change how you take a medicine.
Metformin can affect how well other drugs work, and some drugs can affect how well metformin works.
Some medicines may cause high blood sugar.What should I avoid while taking metformin hydrochloride tablets?Do not drink a lot of alcoholic drinks while taking metformin.
This means you should not binge drink for short periods, and you should not drink a lot of alcohol on a regular basis.
Alcohol can increase the chance of getting lactic acidosis.What are the side effects of metformin?Lactic Acidosis.
In rare cases, metformin can cause a serious side effect called lactic acidosis.
This is caused by a build-up of lactic acid in your blood.
This build-up can cause serious damage.
Lactic acidosis caused by metformin is rare and has occurred mostly in people whose kidneys were not working normally.
Lactic acidosis has been reported in about one in 33,000 patients taking metformin over the course of a year.
Although rare, if lactic acidosis does occur, it can be fatal in up to half the people who develop it.It is also important for your liver to be working normally when you take metformin.
Your liver helps remove lactic acid from your blood.Make sure you tell your doctor before you use metformin if you have kidney or liver problems.
You should also stop using metformin and call your doctor right away if you have signs of lactic acidosis.
Lactic acidosis is a medical emergency that must be treated in a hospital.Signs of lactic acidosis are:feeling very weak, tired, or uncomfortableunusual muscle paintrouble breathingunusual or unexpected stomach discomfortfeeling coldfeeling dizzy or lightheadedsuddenly developing a slow or irregular heartbeatIf your medical condition suddenly changes, stop taking metformin and call your doctor right away.
This may be a sign of lactic acidosis or another serious side effect.Other Side Effects.
Common side effects of metformin include diarrhea, nausea, and upset stomach.
These side effects generally go away after you take the medicine for a while.
Taking your medicine with meals can help reduce these side effects.
Tell your doctor if the side effects bother you a lot, last for more than a few weeks, come back after they’ve gone away, or start later in therapy.
You may need a lower dose or need to stop taking the medicine for a short period or for good.About 3 out of every 100 people who take metformin have an unpleasant metallic taste when they start taking the medicine.
It lasts for a short time.Metformin rarely causes hypoglycemia (low blood sugar) by itself.
However, hypoglycemia can happen if you do not eat enough, if you drink alcohol, or if you take other medicines to lower blood sugar.General advice about prescription medicinesIf you have questions or problems, talk with your doctor or other healthcare provider.
You can ask your doctor or pharmacist for the information about metformin that is written for healthcare professionals.
Medicines are sometimes prescribed for purposes other than those listed in a patient information leaflet.
Do not use metformin for a condition for which it was not prescribed.Do not share your medicine with other people.Watson Laboratories, Inc.Corona, CA 92880 USA
Metformin hydrochloride tablets, as monotherapy, are indicated as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes.Metformin is indicated in patients 10 years of age and older.Metformin may be used concomitantly with a sulfonylurea or insulin to improve glycemic control in adults (17 years of age and older).
Metformin hydrochloride tablets are contraindicated in patients with:Renal disease or renal dysfunction (e.g., as suggested by serum creatinine levels ? 1.5 mg/dL [males], ? 1.4 mg/dL [females] or abnormal creatinine clearance) which may also result from conditions such as cardiovascular collapse (shock), acute myocardial infarction, and septicemia (see WARNINGS and PRECAUTIONS).Congestive heart failure requiring pharmacologic treatment.Known hypersensitivity to metformin hydrochloride.Acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma.
Diabetic ketoacidosis should be treated with insulin.Metformin should be temporarily discontinued in patients undergoing radiologic studies involving intravascular administration of iodinated contrast materials, because use of such products may result in acute alteration of renal function.(See also PRECAUTIONS.)
Lactic acidosis is a rare, but serious, metabolic complication that can occur due to metformin accumulation during treatment with metformin; when it occurs, it is fatal in approximately 50% of cases.
Lactic acidosis may also occur in association with a number of pathophysiologic conditions, including diabetes mellitus, and whenever there is significant tissue hypoperfusion and hypoxemia.
Lactic acidosis is characterized by elevated blood lactate levels (>5 mmol/L), decreased blood pH, electrolyte disturbances with an increased anion gap, and an increased lactate/pyruvate ratio.
When metformin is implicated as the cause of lactic acidosis, metformin plasma levels >5 mcg/mL are generally found.The reported incidence of lactic acidosis in patients receiving metformin hydrochloride is very low (approximately 0.03 cases/1000 patient-years, with approximately 0.015 fatal cases/1000 patient-years).
In more than 20,000 patient-years exposure to metformin in clinical trials, there were no reports of lactic acidosis.
Reported cases have occurred primarily in diabetic patients with significant renal insufficiency, including both intrinsic renal disease and renal hypoperfusion, often in the setting of multiple concomitant medical/surgical problems and multiple concomitant medications.
Patients with congestive heart failure requiring pharmacologic management, in particular those with unstable or acute congestive heart failure who are at risk of hypoperfusion and hypoxemia, are at increased risk of lactic acidosis.
The risk of lactic acidosis increases with the degree of renal dysfunction and the patient’s age.
The risk of lactic acidosis may, therefore, be significantly decreased by regular monitoring of renal function in patients taking metformin and by use of the minimum effective dose of metformin.
In particular, treatment of the elderly should be accompanied by careful monitoring of renal function.
Metformin treatment should not be initiated in patients ? 80 years of age unless measurement of creatinine clearance demonstrates that renal function is not reduced, as these patients are more susceptible to developing lactic acidosis.
In addition, metformin should be promptly withheld in the presence of any condition associated with hypoxemia, dehydration or sepsis.
Because impaired hepatic function may significantly limit the ability to clear lactate, metformin should generally be avoided in patients with clinical or laboratory evidence of hepatic disease.
Patients should be cautioned against excessive alcohol intake, either acute or chronic, when taking metformin hydrochloride tablets, since alcohol potentiates the effects of metformin hydrochloride on lactate metabolism.
In addition, metformin should be temporarily discontinued prior to any intravascular radiocontrast study and for any surgical procedure (see also PRECAUTIONS).The onset of lactic acidosis often is subtle, and accompanied only by nonspecific symptoms such as malaise, myalgias, respiratory distress, increasing somnolence and nonspecific abdominal distress.
There may be associated hypothermia, hypotension and resistant bradyarrhythmias with more marked acidosis.
The patient and the patient's physician must be aware of the possible importance of such symptoms and the patient should be instructed to notify the physician immediately if they occur (see also PRECAUTIONS).
Metformin hydrochloride tablets should be withdrawn until the situation is clarified.
Serum electrolytes, ketones, blood glucose and, if indicated, blood pH, lactate levels and even blood metformin levels may be useful.
Once a patient is stabilized on any dose level of metformin, gastrointestinal symptoms, which are common during initiation of therapy, are unlikely to be drug related.
Later occurrence of gastrointestinal symptoms could be due to lactic acidosis or other serious disease.Levels of fasting venous plasma lactate above the upper limit of normal but less than 5 mmol/L in patients taking metformin do not necessarily indicate impending lactic acidosis and may be explainable by other mechanisms, such as poorly controlled diabetes or obesity, vigorous physical activity or technical problems in sample handling.
(See also PRECAUTIONS.)Lactic acidosis should be suspected in any diabetic patient with metabolic acidosis lacking evidence of ketoacidosis (ketonuria and ketonemia).Lactic acidosis is a medical emergency that must be treated in a hospital setting.
In a patient with lactic acidosis who is taking metformin, the drug should be discontinued immediately and general supportive measures promptly instituted.
Because metformin hydrochloride is dialyzable (with a clearance of up to 170 mL/min under good hemodynamic conditions), prompt hemodialysis is recommended to correct the acidosis and remove the accumulated metformin.
Such management often results in prompt reversal of symptoms and recovery.(See also CONTRAINDICATIONS and PRECAUTIONS.)