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.
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 diabetes medicine dosing changes 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 immediate emergency medical help.
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.
Tell your doctor if you have bloody urine, decrease in how much or how often you urinate, painful or difficult urination, lower back or side pain, fever, chills, or swelling of the face, finger, or lower legs. These may be symptoms of a serious kidney problem.
Let your doctor or dentist know you are using this medicine. Your doctor may advise you to stop using this medicine before you have major surgery or diagnostic tests, especially tests that use a contrast dye.
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, glyburide). The symptoms of low blood sugar must be treated before they cause you to pass out. People feel different symptoms with low blood sugar. It is important that you learn which symptoms you usually have so you can treat it quickly. Some symptoms of low blood sugar include: behavior changes that are similar to being drunk, blurred vision, cold sweats, confusion, cool, pale skin, difficulty with thinking, drowsiness, excessive hunger, a fast heartbeat, headaches that continue, nausea, shakiness, slurred speech, or unusual tiredness or weakness. Talk to your doctor about how to treat low blood sugar.
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.
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.
This medicine may increase your risk for bladder cancer and should not be used in patients with active bladder cancer. Check with your doctor right away if you have blood in your urine or pain while urinating.
Do not drink a lot of alcohol while you are using this medicine. Heavy alcohol use can increase your risk for lactic acidosis.
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, 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.
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.
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.