From the Guidelines
Metformin is not recommended as a primary treatment for type 1 diabetes mellitus, but it may be considered as an adjunctive therapy in certain cases, such as overweight or obese patients, or those with insulin resistance, under close medical supervision. Type 1 diabetes requires insulin therapy as the mainstay of treatment because these patients cannot produce insulin due to autoimmune destruction of pancreatic beta cells. According to the most recent study 1, the addition of metformin in adults with type 1 diabetes caused small reductions in body weight and lipid levels but did not improve A1C.
Key Points to Consider
- Metformin may be used as an adjunctive therapy in type 1 diabetes to reduce insulin requirements and assist with weight management, particularly in patients who are overweight or obese, or have insulin resistance 1.
- The medication works by decreasing hepatic glucose production, increasing peripheral glucose uptake, and improving insulin sensitivity.
- Potential side effects include gastrointestinal disturbances (diarrhea, nausea), vitamin B12 deficiency with long-term use, and rarely lactic acidosis.
- Metformin does not replace the need for insulin therapy in type 1 diabetes and should only be used under medical supervision as part of a comprehensive treatment plan.
Clinical Evidence
The 2023 study 1 provides the most recent and highest quality evidence on the use of metformin in type 1 diabetes, and it suggests that metformin may have a role as an adjunctive therapy in certain cases. However, the benefits and risks of metformin in type 1 diabetes need to be carefully evaluated, and its use should be individualized based on patient characteristics and medical history.
Treatment Approach
When considering the use of metformin in type 1 diabetes, it is essential to weigh the potential benefits against the potential risks and to closely monitor patients for any adverse effects. The dosage of metformin typically ranges from 500-2000 mg daily, often divided into two doses. Regular monitoring of blood glucose levels, insulin requirements, and potential side effects is crucial to ensure the safe and effective use of metformin in type 1 diabetes.
From the FDA Drug Label
Metformin hydrochloride tablets are used with diet and exercise to help control high blood sugar (hyperglycemia) in adults with type 2 diabetes. Metformin hydrochloride tablets are not for people with type 1 diabetes. Before taking metformin hydrochloride Tablets, tell your healthcare provider if you: have type 1 diabetes. Metformin hydrochloride tablets should not be used to treat people with type 1 diabetes
Metformin is not used in the treatment of type 1 diabetes mellitus.
- The drug label explicitly states that metformin hydrochloride tablets are not for people with type 1 diabetes.
- It is essential to follow the recommended usage and precautions to avoid any potential adverse effects. 2 2
From the Research
Metformin in Type 1 Diabetes
- Metformin is sometimes used off-label in the treatment of type 1 diabetes mellitus to improve glycemic control and limit insulin dose requirement 3, 4.
- A pilot study found that metformin adjunctive therapy with insulin improved glycemic control in patients with type 1 diabetes mellitus, with seven out of 10 patients showing an average decrease in HbA(1c) of 11% from pretreatment 3.
- Another study compared the effects of adjunctive therapy with metformin and acarbose in patients with type 1 diabetes mellitus, and found that metformin had a superior impact on fasting blood sugar (FBS) and HbA1C decline, while acarbose had a noteworthy influence on 2-hour postprandial (2hpp) and regular insulin intake control 5.
- The REducing with MetfOrmin Vascular Adverse Lesions (REMOVAL) trial suggested that metformin therapy in type 1 diabetes can reduce atherosclerosis progression, weight, and LDL-cholesterol levels, providing a new perspective on metformin therapy in type 1 diabetes 4.
- However, it is worth noting that most of the studies and guidelines focus on the use of metformin in type 2 diabetes, and its use in type 1 diabetes is not as well established 6, 7.
Key Findings
- Metformin can improve glycemic control in patients with type 1 diabetes mellitus when used as an adjunctive therapy with insulin 3, 5.
- Metformin may have a role in reducing the long-term risk of cardiovascular disease in patients with type 1 diabetes 4.
- The use of metformin in type 1 diabetes is not as well established as its use in type 2 diabetes, and more research is needed to fully understand its effects and potential benefits 6, 7.