What You Need to Know About Metformin
If you’re looking at medications to control Diabetes, you may be considering a preparation with metformin. Before you start taking any medication for Diabetes, you should learn everything you can about it.
What is metformin?
Metformin is used alone or with other medications, including insulin, to treat type 2 Diabetes (the body becomes resistant to insulin and doesn’t process it properly).1 Metformin is sold under several brand names.
What Does metformin Do? Does it work?
Metformin decreases the amount of glucose made by the liver and increases the body’s response to insulin, a natural substance that controls the amount of glucose in the blood. Metformin is used to treat type 2 diabetes, it is not used to treat type 1 diabetes (also called “juvenile Diabetes,” a condition in which the body doesn’t produce insulin and can’t control the amount of sugar in the blood).2
Studies have shown the metformin is effective in reducing patients’ blood glucose levels and is mostly well tolerated by patients.3
What should I go over with my doctor before I decide to take metformin?
Metformin can cause a deficiency of Vitamin B12 and nerve damage caused by this deficiency. This condition can be arrested with Vitamin B12 replacement.4
Metformin can very rarely cause a condition called “lactic acidosis,” which can be fatal.5
Some patients have experienced symptoms and signs of liver damage,6 although some studies have reported that metformin does not affect the liver and is often beneficial in patients with nonalcoholic fatty liver disease.7
What if I’m already taking metformin?
Never stop taking any prescription medication without talking to your doctor first. If you are already taking metformin and are concerned about side effects, talk to your doctor. Your doctor can perform tests to monitor your liver and prescribe treatments to prevent Vitamin B12 deficiency and monitor you for the symptoms of lactic acidosis.
Learn everything you can about metformin before you start taking it.
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1 PubMed Health, “Metformin,” (revised 15 August 2012) http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000974/2 PubMed Health, “Metformin,” (revised 15 August 2012) http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000974/
3 Am J Med, Garber AJ et al., “Efficacy of metformin in type II diabetes: results of a double-blind, placebo-controlled, dose-response trial” (December 1997) http://www.ncbi.nlm.nih.gov/pubmed/9428832; Diabetes Care, , “Efficacy of metformin in the treatment of NIDDM. Meta-analysis” (January1999) http://www.ncbi.nlm.nih.gov/pubmed/10333900
4 South Med. J, Bell DS, “Metformin-induced vitamin B12 deficiency presenting as a peripheral neuropathy,” (March 2010) http://www.ncbi.nlm.nih.gov/pubmed/20134380
5 Food and Drug Administration, “Metformin Hydrochloride Tablets,” http://www.fda.gov/ohrms/dockets/dailys/02/May02/053102/800471e6.pdf
6 Diabetes Forms, patient forum, http://www.diabetesforums.com/forum/type-2-diabetes/10944-metformin-affecting-the-liver.html; NIH LiverTox, “Metformin”, (retrieved 20 October 2012), http://livertox.nih.gov/Metformin.htm
7 J Am Pharm Assoc, Brackett CC, “Clarifying metformin’s role and risks in liver dysfunction” (May-June 2010) http://www.ncbi.nlm.nih.gov/pubmed/20452916