Metformin Side Effects

Metformin

Metformin Side Effects: Brand names Glucophage, Fortamet, Glumetza, and Riomet. Available in 500, 850 and 1000 mg tablets. Metformin is primarily used as an oral medication to help control blood sugar in type 2 diabetes mellitus. It is also used off label for treatment of polycystic ovarian syndrome and infertility associated with PCOS. The good news with metformin is that except for gastrointestinal side effects which though common tend to be minor in most patients, and are often dose related, meaning if you reduce the dose they may resolve, metformin side effects are uncommon. Except for the rare lactic acidosis discussed below silent or serious metformin side effects are rare. For these reasons, plus the fact that unlike most oral diabetes medications that can lead to hypoglycemia (low blood sugar) metformin does not cause hypoglycemia, the inexpensive generic form of metformin is often the first choice in treatment of type 2 diabetes.

Black Box Warning: Metformin can cause lactic acidosis in rare cases, estimated to be about 0.3/1000 users, and usually in patients with significant renal impairment, often with multiple serious medical problems. See the manufacturers prescribing guidelines for details on this issue. (Metformin us contraindicated in patients with renal dysfunction, and usually not prescribed to men with a serum creatinine > 1.5 or women with a serum creatinine > 1.2. Serum creatinine is an indicator of renal function.) Symptoms of lactic acidosis can be mild at first and progress to a severe life threatening condition. Typical symptoms include muscle pains, muscle weakness, trouble breathing, stomach or abdominal pain, coldness or numbness in the extremities, and irregular or rapid heart rate or dizziness. Any of these symptoms should lead to prompt medical evaluation on an emergency basis.

Common Metformin Side Effects: The most common side effects of metformin are in the gastrointestinal tract. Diarrhea is the most common metformin side effect, sometimes associated with gas, bloating and abdominal discomfort. Other common metformin side effects are loss of appetite, occasional weight loss and nausea of vomiting. Occasionally patients get a metallic taste in the mouth and rashes and headache happen occasionally.

Life Threatening Metformin Side Effects: Lactic acidosis is the most serious of these, see above under black box warnings. Megaloblastic anemia is another potential serious metformin side effect, but is also unusual.

Unusual Metformin Side Effects: The metallic taste in the mouth is about it here. Metformin should be stopped prior to the use of iodine containing IV contrast dyes, as acute renal injury is more common when these dyes are used while on metformin.

Metformin Drug Interactions: Heavy alcohol use can make metabolic acidosis more likely, and should be avoided Cimetdine should be avoided, but there are plenty of other H2-blocker acid reducing medications like ranitidine and famotidine that can be substituted. The list of less significant interactions is long, and is most notable for digoxin, other hypoglycemic to which the effect of lowering blood sugar can be additive. (most of the time this is desirable).

Pregnancy and Lactation Class: Metformin is pregnancy category B and is felt to be probably safe in lactation.

Special Considerations: Overall metformin is a commonly used and with the exception of the rare lactic acidosis very safe medication. Most metformin side effects are symptomatic enough to lead patients to discuss them with their physician. There is some evidence that use of metformin in pre-diabetes may delay or prevent progression to type 2 diabetes. Metformin is on the generic discount pharmacies inexpensive medications list at most if not all of the discount pharmacies. Overall other than loose bowels or diarrhea metformin side effects are uncommon.