Comparing metformin extended-release to metformin immediate-release for adults with type 2 diabetes.

This study compared the effectiveness and tolerance of metformin (Glucophage) extended-release (MXR) and conventional metformin immediate-release (MIR) in adults with type 2 diabetes (T2D). The authors concluded that MIR had better glucose control while MXR but reduced gastrointestinal (GI) side effects.

T2D is a chronic, progressive disease. Effective management includes lifestyle modification and medical treatment such as metformin. At recommended doses, MIR formulations can cause GI side effects. As a result, some patients may not adhere to treatment. This can lead to poor blood glucose control. 

MXR is an alternative to MIR and is administered once daily. The slow delivery of MXR reduces GI side effects and possibly leads to better adherence to treatment. The amount of MRX that reaches the blood circulation does not vary with dosing or meal intakes. MRX has been considered just as effective as MIR but with lower GI side effects. However, there is a need to confirm this by reviewing data from clinical trials in adults with T2D.  

This study analyzed 9 clinical trials that compared equal daily doses of MXR and MIR treatments in adults with T2D. Overall, 2609 patients were included in the study. Long-term blood glucose control was evaluated through the HbA1c levels (blood glucose over the past 2-3 months). 

The lowering of HbA1c levels compared to before treatment was 0.09% better with MIR compared to MXR. MIR also improved cholesterol and triglyceride (blood fats) levels compared to MXR. However, the risk of indigestion was 42% lower with MXR compared to MIR. 

The other glucose parameters and GI symptoms were not significantly different between MIR and MXR.

The study found that MIR had a better HbA1c lowering effect while MXR reduced indigestion in patients with T2D.

The studies analyzed had different protocols. The metformin doses were different among studies and the treatment periods also varied.