What side effects are possible with this medication?
A side effect is an unwanted response to a medication when it is taken in normal doses. A side effect may be mild or severe, temporary or permanent, but does not occur in everyone. Not everyone will experience side effects, and which side effects a person experiences cannot be anticipated.
The following side effects have been reported by at least 1% of people taking this medication. If you develop any of these side effects (or any other side effects not listed here) or they change in intensity, speak to your doctor or pharmacist for advice on managing them and on the risks and benefits of the medication.
- diarrhea
- flatulence (passing of gas)
- loss of appetite
- metallic taste in mouth
- nausea
- stomach ache
- vomiting
- weight loss
Click here to learn about serious side effects that can potentially occur with any medication. These examples are provided for information purposes only and are not meant to be exhaustive. Always consult your doctor for sound medical advice specific to your particular medication and treatment.
Are there any other precautions or warnings for this medication?
Be sure to inform your doctor of all your medical conditions before you begin taking a medication. Some conditions can affect how you should take this medication.
Alcohol intake: Anyone taking metformin extended-release should avoid excessive alcohol intake. Alcohol increases the risk of lactic acid buildup (lactic acidosis) with metformin. If you have fatigue, muscle aches, abdominal pain, or trouble breathing while taking metformin, seek immediate medical attention.
Blood glucose control: When a person taking metformin extended-release experiences fever, trauma, infection, or surgery, a temporary loss of blood glucose control may occur. It may be necessary to stop the medication and temporarily inject insulin. Metformin extended-release may be started again after the problem is resolved.
Blood glucose monitoring: Monitor your blood glucose at regular intervals as discussed with your doctor or diabetes specialist.
Diet: Metformin extended-release is a treatment to be taken in combination with a proper diet. It is not a substitute for proper diet.
Lactic acidosis: Lactic acidosis is a rare but serious condition that occurs when metformin accumulates in the body (i.e., the body doesn't get rid of it fast enough) during treatment. People with severe kidney disease are at higher risk of developing lactic acidosis. When it does occur (very rarely), it is fatal in about 50% of cases. People with kidney or liver disease should be monitored very closely by their doctor while taking metformin extended-release.
Low blood glucose: Under usual circumstances, low blood glucose does not occur for people who take only metformin extended-release. However, low blood glucose could occur if you haven't eaten enough food, and especially if you exercise strenuously while taking this or consume amounts of alcohol.
Reduced response: Over time, people may become progressively less responsive to a particular treatment for diabetes because their diabetes worsens. If metformin extended-release fails to lower blood glucose to target levels, talk to your doctor. Your doctor may want to stop the medication or recommend another one.
Surgery: Metformin extended-release should be stopped temporarily for any surgical procedure associated with a restricted food and drink intake.
Vitamin B12 levels: Blood levels of vitamin B12 may drop in people taking metformin extended-release. This can be corrected by taking vitamin B12 supplements. Vitamin levels should be monitored by your doctor regularly.
Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, stop taking it immediately and call your doctor.
Breast-feeding: This medication may pass into breast milk. If taking metformin extended-release is considered essential, stop breast-feeding.
Children: The safety and effectiveness of this medication have not been established for children under 17 years of age.
What other drugs could interact with this medication?
An interaction between medications does not always mean that you must stop taking one of them. The following medications may affect the way metformin extended-release works, be affected by metformin extended-release, or increase the risk of side effects:
- alcohol
- amiloride
- birth control pills
- calcium-channel-blocking medications (e.g., nifedipine, verapamil)
- cimetidine
- clofibrate
- corticosteroids (e.g., prednisone, hydrocortisone)
- digoxin
- diuretics (water pills, e.g., hydrochlorothiazide, triamterene, furosemide)
- estrogen
- iodinated contrast material (dyes used for medical tests)
- isoniazid
- morphine
- MAO inhibitors (e.g. phenelzine, tranylcypromine)
- nicotinic acid
- nifedipine
- phenothiazines (e.g., methotrimeprazine, fluphenazine)
- phenylbutazone
- phenyotin
- probenacid
- procainamide
- propranolol
- quinidine
- quinine
- ranitidine
- salicylates
- sulfonamides
- sulfonylureas
- sympathomimetics(e.g., pseudoephedrine, epinephrine)
- thyroid products (e.g., levothyroxine)
- trimethoprim
- vancomycin
- warfarin
If you are taking any of these or other medications (including non-prescription, herbal, and supplement products), speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want to change your therapy or suggest ways of managing any interactions. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your doctor know if you use them.