Key takeaways
Metformin (Glumetza, Riomet) and Avandia (rosiglitazone) are both oral medications used to treat Type 2 diabetes. They help control blood sugar levels, but they belong to different medication classes. Metformin is a biguanide that works by lowering the amount of sugar your body makes and helps your body use insulin better. Avandia, on the other hand, is a thiazolidinedione that improves your body's ability to use insulin. Metformin is usually taken once or twice daily with food (to reduce stomach upset), while Avandia can be taken once or twice daily with or without food. Metformin is available in both short-acting and long-acting forms and is generally less expensive than Avandia. Common side effects of metformin include diarrhea and nausea, while Avandia may cause weight gain and swelling from fluid buildup. Both medications can cause low blood sugar, especially when combined with other diabetes medications. Avandia can also increase the risk of heart failure and heart attacks.
