Precautions

It is very important that your doctor check your progress at regular visits, especially during the first few weeks that you take this medicine. Blood and urine tests may be needed to check for unwanted effects.

Using this medicine during the second and third part of your pregnancy can harm your unborn baby. If you think you have become pregnant while using this medicine, tell your doctor right away.

This medicine may cause some women who do not have regular monthly periods to ovulate. This can increase the chance of pregnancy. If you are a woman of childbearing potential, you should discuss birth control options with your doctor.

It is very important to follow carefully any instructions from your doctor about:

  • Alcohol—Drinking alcohol may cause severe low blood sugar. Discuss this with your doctor.
  • Other medicines—Do not take other medicines unless they have been discussed with your doctor. This especially includes nonprescription medicines such as aspirin, and medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems.
  • Counseling—Other family members need to learn how to prevent side effects or help with side effects if they occur. Also, patients with diabetes may need special counseling about the changes in the dosing of their diabetes medicine that might occur because of lifestyle changes, such as changes in exercise and diet. Furthermore, counseling on contraception and pregnancy may be needed because of the problems that can occur in patients with diabetes during pregnancy.
  • Travel—Keep a recent prescription and your medical history with you. Be prepared for an emergency as you would normally. Make allowances for changing time zones and keep your meal times as close as possible to your usual meal times.
  • In case of emergency—There may be a time when you need emergency help for a problem caused by your diabetes. You need to be prepared for these emergencies. It is a good idea to wear a medical identification (ID) bracelet or neck chain at all times. Also, carry an ID card in your wallet or purse that says that you have diabetes and a list of all of your medicines.

Under certain conditions, too much metformin can cause a serious condition, called lactic acidosis. The symptoms of lactic acidosis are severe and appear quickly. Lactic acidosis usually occurs when other serious health problems are present, such as a heart attack or kidney failure. The symptoms of lactic acidosis include: abdominal or stomach discomfort, decreased appetite, diarrhea, fast or shallow breathing, a general feeling of discomfort, muscle pain or cramping, and unusual sleepiness, tiredness, or weakness. If you have more than one of these symptoms together, you should get emergency medical help right away.

This medicine may increase your risk of having leg, toe, or midfoot amputation (leg removal surgery). Check with your doctor right away if you have pain, tenderness, sores or ulcers, or infections on your leg or foot.

Dizziness, lightheadedness, or fainting may occur with this medicine. This is more common if you have kidney disease, low blood pressure, or if you are taking a diuretic (water pill). Taking plenty of fluids each day may help. Drink plenty of water during exercise or in hot weather. Check with your doctor if you have severe nausea, vomiting, or diarrhea that does not stop. This may cause you to lose too much water.

Ketoacidosis (high ketones and acid in the blood) may occur while you are using this medicine. This can be life-threatening and requires immediate medical attention. Your doctor may give you insulin, fluid, and carbohydrate replacement to treat this condition. Tell your doctor right away if you have nausea, vomiting, trouble breathing, increased thirst or urination.

Check with your doctor right away if you have bloody urine, decrease in how much or how often you urinate, an increase in blood pressure, increased thirst, loss of appetite, lower back or side pain, nausea, swelling of the face, fingers, or lower legs, troubled breathing, unusual tiredness or weakness, vomiting, or weight gain. These could be symptoms of a serious kidney problem.

This medicine may cause vaginal yeast infections in women and yeast infections of the penis in men. This is more common in patients who have a history of genital yeast infections or in men who are not circumcised. Women may have a vaginal discharge, itching, or odor. Men may have redness, itching, swelling, or pain around the penis, or a discharge with a strong odor from the penis. Check with your doctor right away if you have any of these symptoms.

This medicine may increase risk of having urinary tract infections, including pyelonephritis or urosepsis. Check with your doctor right away if you have bladder pain, bloody or cloudy urine, difficult, burning, or painful urination, or lower back or side pain.

Serious allergic reactions may occur with this medicine. Check with your doctor right away if you have a skin rash, hives or welts, itching, redness of the skin, trouble breathing, or large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals.

This medicine may cause a rare but serious bacterial infection, called necrotizing fasciitis of the perineum or Fournier's gangrene, which can cause damage to the tissue under the skin in the area between and around the anus and genitals (perineum). Fournier's gangrene may lead to hospitalization, multiple surgeries, or death. Check with your doctor right away if you have fever, unusual tiredness or weakness, or pain, tenderness, redness, or swelling of the area between and around your anus and genitals.

Do not drink a lot of alcohol while you are using this medicine. Heavy alcohol use can increase your risk for lactic acidosis.

This medicine may increase the risk of bone fractures. Ask your doctor about ways to keep your bones strong to help prevent fractures.

This medicine may cause hypoglycemia (low blood sugar). This is more common when this medicine is taken together with other diabetes medicines (eg, insulin, glipizide, or glyburide). Low blood sugar must be treated before it causes you to pass out (unconsciousness). People feel different symptoms of low blood sugar. It is important that you learn which symptoms you usually have so you can treat it quickly. Talk to your doctor about the best way to treat low blood sugar.

Hyperglycemia (high blood sugar) may occur if you do not take enough or skip a dose of your diabetes medicine, overeat, or do not follow your diet plan, have a fever or infection, or do not exercise as much as usual. Some symptoms of high blood sugar include: blurred vision, drowsiness, dry mouth, flushed and dry skin, a fruit-like breath odor, increased frequency and amount of urination, ketones in the urine, loss of appetite, nausea or vomiting, rapid and deep breathing, tiredness, or unusual thirst. If symptoms of high blood sugar occur, check your blood sugar level and call your doctor for instructions.

Let your doctor or dentist know you are taking this medicine. Your doctor may advise you to stop taking this medicine before you have major surgery or diagnostic tests, especially tests with contrast dye.

Make sure any doctor or dentist who treats you knows that you are using this medicine. This medicine may affect the results of certain medical tests (eg, urine glucose tests may not be accurate).

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.