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Medication Overview Metformin (Glucophage) for Diabetes
Metformin is a drug belonging to the biguanide class of medications. The Food and Drug Administration (FDA) approved metformin as an antidiabetic agent in 1994 for the treatment of type II diabetes. It is incredibly effective at lowering blood sugar levels and reducing complications and death related to diabetes.
Though metformin is a common and effective drug, it is important to know the details of the medication prior to starting it. This article will discuss metformin, including its use cases, side effects, precautions, and more.
Medical Indications
Metformin is commonly used to treat type II diabetes. Diabetes is a condition affecting over 27 million individuals in the United States, accounting for 10 percent of the population. Type II diabetes is characterized by issues involving insulin, a hormone produced by the pancreas that regulates your body’s blood sugar levels. Individuals with type II diabetes may have insulin resistance, meaning their body does not respond appropriately to insulin.
This results in abnormally high blood sugar levels over an extended period of time. Over time, hyperglycemia (high blood sugar) leads to health complications such as vision loss, kidney disease, and heart disease. These complications can be life-threatening.
The American Diabetes Association (ADA) recommends metformin as a first-line therapy for treating type 2 diabetes in adults and children older than ten. In particular, a hemoglobin A1C (HbA1C) level of less than 9 percent would be indicated for metformin monotherapy, while an HbA1C level of greater than 9 percent would be indicated for metformin in combination with another agent.
Doctors recommend that metformin be taken in conjunction with improvements in diet and exercise. These lifestyle interventions, when used together with metformin, can further lower hyperglycemia (also known as high blood sugar).
Off-Label Usage for Metformin (Glucophage) for Diabetes
- Gestational diabetes. Gestational diabetes is a subtype of diabetes that can be experienced during pregnancy, occurring in individuals who do not have pre-existing diabetes. Gestational diabetes affects up to 10 percent of pregnancies in the US (3).
- Polycystic ovary syndrome (PCOS). Metformin can help treat symptoms of PCOS, a hormonal condition in women. Metformin may be able to decrease weight, lower abnormal hormone levels, induce ovulation, and more (4).
- Prevention of type 2 diabetes. Studies have found that metformin therapy is not just for those with existing diabetes. It can actually prevent or delay diabetes for those at increased risk of the disease (5).
- Antipsychotic weight gain. Because of metformin’s effects in reducing weight, it can help to treat weight gain caused by antipsychotic therapy.
Research is also evaluating metformin’s use cases in other conditions, such as cancer and neuroprotection.
Dosage and Administration of Metformin (Glucophage) for Diabetes
Metformin is available in two oral formulations: immediate-release (IR) and extended release (ER). The dose of metformin will depend on which formulation you take. Typical directions are as follows:
- Immediate release. With the IR formulation, there are two potential starting doses: 500 mg once or twice times daily or 850 mg once daily. These doses can be increased in 500 or 850 mg increments weekly. The usual dose of IR metformin is 850 or 1,000 mg twice daily.
- Extended release. With the ER formulation, the recommended starting dose is either 500 or 1,000 mg once daily. From there, doses can be increased by 500 mg a week up to a maximum dose of 2,000 mg daily.
Other Indications of Metformin (Glucophage) for Diabetes
- Type 2 diabetes prevention
- IR: Start at 850 mg daily for one month. Can be increased to 850 mg twice daily if needed.
- Antipsychotic-associated weight gain
- IR: Start anywhere between 750 to 2,000 mg in two to three divided doses. Maximum daily dose in studies is 2,550 mg.
- ER: Start at 500 mg daily. This can be increased every two to six weeks depending on tolerability to a maximum of 1,000 to 2,000 mg daily.
- Gestational diabetes
- IR: Start with 500 mg once or twice daily. Can increase to 2,000 to 2,500 mg daily in two to three divided doses.
- PCOS
- IR: Start with 500 mg once or twice daily. Can be increased in increments of 500 mg weekly (1).
The above dosing is only the typical dosing for metformin. Always consult with your healthcare provider as to what dose you should take of your medication. Metformin should also be taken with an entire glass of water with dinner.
Potential Side Effects of Metformin (Glucophage) for Diabetes
Metformin is a relatively safe drug, typically only causing minor side effects. The most common side effects are gastrointestinal (GI) related, including things like nausea, vomiting, diarrhea, stomach pain, and decreased appetite.
PatientsLikeMe members data:
- 39% of patients on PatientsLikeMe who reported using metformin said they have diarrhea.
- Additional top reported symptoms include nausea, stomach pain, abdominal cramps, and weight gain.
Although metformin is generally safe, it has been known to cause more serious side effects in rare cases. These are as follows:
- Vitamin B12 deficiency. Signs of this deficiency include fatigue, weakness, yellowing of the skin, vision issues, a red or sore tongue, or mouth ulcers.
- Hypoglycemia (low blood sugar). Because metformin is an antidiabetic agent, it is meant to lower blood sugar. When taken with other blood-sugar lowering agents, like insulin, it can make levels go too low. Signs of low blood sugar are shaking, confusion, hunger, trouble concentrating, and sweating.
- Lactic acidosis. Lactic acidosis is when too much acid builds up in the blood. It can happen when you take metformin and have other related conditions, such as kidney or liver issues, dehydration, surgery, heart attack, stroke, infection, or binge drinking. Signs of lactic acidosis include dizziness, weakness, cold hands and/or feet, fatigue, muscle pain, irregular heartbeat, difficulty breathing, nausea, vomiting, or stomach pain (6).
Precautions and Contraindications of Metformin (Glucophage) for Diabetes
There are several contraindications with metformin. If you have any of the following, you should not take metformin:
- Severe renal impairment
- Allergy to metformin
- Metabolic acidosis
Discuss with your healthcare provider if you have any of the above.
Interactions of Metformin (Glucophage) for Diabetes
Certain medications may interact with metformin, changing the way it works or increasing your risk for certain side effects. Drugs that can interact with metformin include furosemide, nifedipine, and carbonic anhydrase inhibitors (e.g., topiramate). Alcohol can also increase the effects of metformin on lactate metabolism in the body, increasing your risk of lactic acidosis.
Other drugs may also interact with metformin. Always let your healthcare provider know what medications you are on. If they find one may interact with metformin, you may require a dose adjustment, change in therapy, or discontinuation of therapy.
Effectiveness and Expectations of Metformin (Glucophage) for Diabetes
Metformin is very effective in treating diabetes. A study known as the United Kingdom Prospective Diabetes Study (UKPDS) showed metformin lowered participant’s risk of any diabetes-related event by 32 percent. Additionally, their risk for diabetes-related death was lowered by 42 percent.
Another study compared different doses of metformin with placebo. In 451 patients, fasting plasma glucose was lowered by 19 to 84 mg/dL, depending on the dose. HbA1c levels were decreased by 0.6 to 2.0 percent, depending on the dose. The efficacy of metformin was dose-dependent, meaning higher doses were associated with increased effectiveness, although even the 500 mg dose was considered effective. The most common side effect was diarrhea.
Long-Term Use and Monitoring
When dealing with antidiabetic agents, it is important to monitor blood sugar levels and HbA1c levels regularly to ensure therapy is working. Providers should also monitor an individual’s renal function, which is important to preventing lactic acidosis. Because vitamin B12 deficiency can also occur, ADA also recommends regular monitoring of vitamin B12 levels.
A majority of PatientsLike Me members who have reported taking Metformin have been taking it for 10+ years. While a majority who have stopped taking metformin stopped after 2-5 years.
Alternatives and Complementary Therapies to Compliment Metformin (Glucophage) for Diabetes
Frequently Asked Questions (FAQs) About Metformin (Glucophage) for Diabetes
How does metformin work?
Metformin belongs to a class of drugs known as biguanides. It exerts its effectiveness through several functions:
- Lowering sugar production in the liver
- Increasing insulin sensitivity
- Lowering absorption in the intestine
Through these mechanisms, metformin can lower blood sugar levels.
What are the most common side effects of metformin?
GI effects are common with metformin, including nausea, vomiting, and diarrhea.
When might I start experiencing side effects?
Side effects can start within the first few weeks of beginning treatment.
How can I minimize side effects with metformin?
It is best to take metformin with a meal to minimize your chances of experiencing a side effect.
Can I take metformin while pregnant?
Metformin can be taken during pregnancy in some cases, but always discuss with your doctor before taking any medications while pregnant. Typically, diabetes is managed with insulin during pregnancy. Alert your doctor if you are planning to get pregnant or are currently pregnant.
Can metformin help me lose weight?
Metformin can cause mild decreases in weight. However, metformin is not a weight loss drug.
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Resources
- https://www.ncbi.nlm.nih.gov/books/NBK518983/#:~:text=The%20off%2Dlabel%20indications%20of,polycystic%20ovary%20syndrome%20(PCOS).
- https://www.cdc.gov/diabetes/basics/diabetes.html
- https://www.cdc.gov/diabetes/basics/gestational.html#:~:text=Gestational%20diabetes%20is%20a%20type,pregnancy%20and%20a%20healthy%20baby.
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3475283/#:~:text=Several%20effects%20have%20been%20reported,gestational%20diabetes%20mellitus%20(GDM).
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6243218/#:~:text=In%20summary%2C%20metformin%20is%20safe,a%20history%20of%20gestational%20diabetes).
- https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/021574s020lbl.pdf
- https://dmsjournal.biomedcentral.com/articles/10.1186/1758-5996-5-6#:~:text=Metformin's%20first%2Dline%20position%20was,cause%20mortality%20(p%20%3D%200.011)
- https://pubmed.ncbi.nlm.nih.gov/9428832/