An Eye Doctors Perspective of Metformin and Type 2 Diabetes
When it comes to Type 2 diabetes, the initial treatment choice for many people is a medication called Metformin. In fact, it's the number one prescribed diabetes medication in Canada.
What is Type 2 Diabetes?
Type 2 diabetes is when cells in your body cannot normally respond to insulin, also known as insulin resistance. Insulin functions by transporting sugar from the blood into cells; however, with an impaired response to insulin, a person builds up excess blood sugar and becomes hyperglycemic. This is where Metformin steps in.
Metformin is part of the biguanide class of medications. It is an antihyperglycemic agent that lowers blood sugar and is often referred to as an insulin sensitizer.
How Does Metformin Work?
Metformin's pharmacologic mechanisms of action are unique compared to other oral diabetes medications. It decreases intestinal absorption of glucose, reduces hepatic glucose production, and improves insulin sensitivity through increased peripheral glucose uptake and utilization.
Reducing the amount of glucose absorbed from food ingested and the amount of glucose made by the liver improves glucose tolerance. In addition, it lowers both the basal (between meals/bedtime) and postprandial (after meals) plasma glucose.
The main objective for people with diabetes is to decrease the sugar in their blood and stabilize it at normal levels.
One of the interesting properties of Metformin is that it does not produce hypoglycemia (under usual circumstances of use) and hyperinsulinemia.
Hypoglycemia (low blood sugar) is a dangerous condition characterized by heart palpitations, shakiness, and anxiety. Hypoglycemia can happen when blood sugar is overcorrected by certain diabetic medications such as sulfonylureas and insulin.
Metformin also does not alter insulin secretion, preventing it from causing hyperinsulinemia, a condition characterized by excess sugar cravings, unusual weight gain, and extreme tiredness.
What Is the Common Dosage of Metformin?
As long as it's not contraindicated, Metformin is considered the first-line treatment for Type 2 Diabetes because it's very cost-effective and efficient.
The initial dosage is usually between 500-1000mg per day. Slowly the dosage may increase to around 2000mg, after which there is a minimal benefit with increased side effects.
Patients may either be prescribed immediate-release or extended-release tablets or a combination of both.
What Are the Side Effects of Metformin for Type 2 Diabetes?
Common side effects of Metformin include diarrhea, nausea, and upset stomach. These will most likely go away after taking the medication for a while and are reduced by taking the medication with meals.
Other less common side effects include:
abnormal stools
hypoglycemia
muscle aches and pain
lightheadedness
shortness of breath
increased sweating
chest discomfort
chills & flu-like symptoms
Flushing and palpitations
Hypoglycemia is rare but can occur if someone does not eat enough, drinks excess alcohol, or takes multiple medications to reduce blood sugar. Around 3% of people experience a metallic taste when first starting metformin but this lasts for a short period.
In addition to these side effects, other serious adverse events need to be monitored. Metformin can cause a buildup of acid in the blood due to its impact on reducing lactate uptake, resulting in a potentially fatal condition called lactic acidosis. Lactic acidosis is a medical emergency that must be treated in the hospital. Signs of lactic acidosis include trouble breathing, feeling dizzy, cold hands or feet, and stomach pains. People are more at risk of this if they have kidney or liver disease, consume alcohol, or have a history of heart attacks or strokes.
Metformin has also been shown to decrease Vitamin B12 levels to subnormal levels in about 7% of patients. This B12 reduction is due to the interference of B12 absorption, which is reversible through discontinuation of the drug or by vitamin B12 supplementation. In addition, low vitamin B12 exacerbates the risk of peripheral neuropathy, impairing nerves that carry messages around the body. Those with a history of low B12 levels or calcium intake should get serum B12 measurements as recommended by their diabetes specialist.
Conclusion:
Metformin is a clinically proven first-line therapy for children (10 years and older) and adults with Type 2 diabetes. The medication alone will not control your diabetes, so people must adhere to dietary instructions and exercise regularly. Diabetes is, unfortunately, one of the leading causes of vision loss and blindness. It's also critical that people with Type 2 diabetes have an annual diabetes eye exam with an optometrist. The eye doctors at Helio Optometry have trained to diagnose the early signs of diabetic eye disease, such as cataracts, diabetic retinopathy, and glaucoma.
