University of Washington

AIDS Clinical Trials Group

Drug Information Sheet




Other Names: Glucophage

Manufacturer: Bristol Myers Squibb

What is it?

Metformin is a medication that is commonly used to help control blood sugar in people with diabetes. In addition to helping control blood sugar, metformin has been shown to help lower certain types of bad fats, such as triglycerides and LDLs and decrease fat accumulation around the waist. For this study, a matching placebo tablet may be used in place of the metformin.


How do I take it?

         Metformin is available as a 500 mg capsule or matching placebo

         The dose may vary, but it is taken every 12 hours. Metformin or matching placebo can be taken with or without food, but it should be taken consistently in the same manner throughout the study. Please refer to your prescription label to be sure you take the study medication correctly. Call your study clinician if you have any questions.


Special Considerations

         Store metformin or matching placebo at a controlled room temperature, out of the reach of children.

         Please bring your medication bottles (empty and partially used) to each study visit.



Some drugs taken together may have interactions that cause illness or impair the effectiveness of the drugs. It is a good idea to always check with your study clinician before taking any other medications, prescription or otherwise, to be sure it will not interact with metformin.


Side Effects

Not everyone experiences side effects. When they do occur, they may be mild, moderate or severe. Some side effects cannot be felt by the patient but can be found through laboratory tests, so it is important to see your study clinician regularly for checkups so that adverse effects can be detected early and treated.


Common side effects associated with metformin include diarrhea, nausea, and upset stomach. These side effects are usually not severe and taking the medication with food lessens the severity. Some people report having a metallic taste in their mouth when they first start taking metformin, but this usually only lasts for a short time. Other possible side effects include hypoglycemia (low blood sugar), vomiting, abdominal bloating, flatulence (gas), loss of appetite, and weight loss. Be sure to call your study clinician if the side effects are severe enough to prevent you from taking your study medication.


Metformin has been associated with an increased risk of developing lactic acidosis, a buildup of lactic acid in the bloodstream. Some of the symptoms of lactic acidosis include:

         Feeling very weak, tired, or uncomfortable

         Trouble breathing

         Feeling cold

         Suddenly developing a slow or irregular heartbeat

         Unusual muscle pain

         Unusual or unexpected stomach discomfort

         Feeling dizzy or lightheaded


Drinking alcohol with metformin may further increase the risk of developing lactic acidosis. Kidney and liver function will be monitored closely as decreased functioning may result in an increased risk of developing lactic acidosis. It is important to notify your study clinician before starting any new medications some medications may decrease kidney function and increase the risk of developing lactic acidosis.


Last Update: 4/23/2002