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Precautions
It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.
It is very important to follow carefully any instructions from your health care team about:
- Alcohol—Drinking alcohol may cause very low blood sugar. Discuss this with your health care team.
- 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. Counseling on birth control and pregnancy may be needed because of the problems that can occur in pregnancy for patients with diabetes.
- Travel—Carry a recent prescription and your medical history. Be prepared for an emergency as you would normally. Make allowances for changing time zones, but 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.
If you are scheduled to have surgery or medical tests that involve x-rays, you should tell your doctor that you are taking metformin. Your doctor will instruct you to stop taking metformin until at least 2 days after the surgery or medical tests. During this time, if your blood sugar cannot be controlled by diet and exercise, you may be advised to take insulin.
Too much metformin, under certain conditions, can cause lactic acidosis. Symptoms of lactic acidosis are severe and quick to appear and usually occur when other health problems not related to the medicine are present and are very severe, such as a heart attack or kidney failure. Symptoms include diarrhea, fast and shallow breathing, severe muscle pain or cramping, unusual sleepiness, and unusual tiredness or weakness.
If symptoms of lactic acidosis occur, you should check your blood sugar and get immediate emergency medical help. Also, tell your doctor if severe vomiting occurs.
Metformin can cause low blood sugar (hypoglycemia). However, it also can occur if you delay or miss a meal or snack, drink alcohol, exercise more than usual, cannot eat because of nausea or vomiting, take certain medicines, or take metformin with another type of diabetes medicine. Symptoms of low blood sugar must be treated before they lead to unconsciousness (passing out). Different people feel different symptoms of low blood sugar. It is important that you learn which symptoms of low blood sugar you usually have so that you can treat it quickly.
Symptoms of low blood sugar include anxiety; behavior change similar to being drunk; blurred vision; cold sweats; confusion; cool, pale skin; difficulty in thinking; drowsiness; excessive hunger; fast heartbeat; headache (continuing); nausea; nervousness; nightmares; restless sleep; shakiness; slurred speech; or unusual tiredness or weakness.
If symptoms of low blood sugar occur, eat glucose tablets or gel, corn syrup, honey, or sugar cubes; or drink fruit juice, non-diet soft drink, or sugar dissolved in water. Also, check your blood for low blood sugar. Glucagon is used in emergency situations when severe symptoms such as seizures (convulsions) or unconsciousness occur. Have a glucagon kit available, along with a syringe or needle, and know how to use it. Members of your household also should know how to use it.
High blood sugar (hyperglycemia) is another problem related to uncontrolled diabetes. Symptoms of mild high blood sugar appear more slowly than those of low blood sugar. These may include blurred vision; drowsiness; dry mouth; flushed, dry skin; fruit-like breath odor; increased urination (frequency and amount); ketones in urine; loss of appetite; sleepiness; stomachache, nausea, or vomiting; tiredness; troubled breathing (rapid and deep); unconsciousness; or unusual thirst.
High blood sugar may occur if you do not exercise as much as usual, have a fever or infection, do not take enough or skip a dose of your diabetes medicine, or overeat or do not follow your meal plan.
If symptoms of high blood sugar occur, check your blood sugar level and then call your doctor for instructions.
