Glucophage (metformin): What it does and how to use it

If you or someone you care for was prescribed Glucophage, you probably want to know the basics fast: what it treats, how to take it, and what to watch for. Glucophage is the brand name for metformin. Doctors use it mainly for type 2 diabetes to lower blood sugar, and it’s one of the most commonly prescribed diabetes drugs worldwide.

How Glucophage works and common doses

Metformin lowers blood sugar by reducing glucose production in the liver and making muscle cells more sensitive to insulin. Typical starting doses are 500 mg once or twice daily with food. Many people ramp up slowly—500 mg week 1, then 1,000 mg, and so on—to reach an effective dose. Most adults do well on 1,500 mg/day, and the usual maximum is about 2,000 mg/day (some formulations go up to 2,550 mg/day under close supervision). There’s an extended‑release (XR) version you take once daily, which often causes fewer stomach problems.

Side effects, tests, and safety rules

The most common side effects are gastrointestinal: nausea, bloating, and diarrhea. Those often fade after a couple of weeks or if you start with a low dose and take the pill with food. Two safety points matter: kidney function and vitamin B12. Many clinicians avoid metformin when eGFR is below 30 mL/min/1.73 m2. If eGFR is 30–45, doctors usually lower the dose or watch labs more closely. Check kidney function before starting and at least once a year after that.

Metformin can reduce vitamin B12 levels over time. Ask your provider to test B12 if you feel tired, have numbness or tingling, or every year if you’ve been on metformin long term. Lactic acidosis is a rare but serious risk—symptoms include extreme tiredness, muscle pain, fast breathing, or feeling cold. That risk rises with severe kidney problems, dehydration, heavy alcohol use, or major infection.

Because of those risks, you may be told to stop metformin temporarily before major surgery or if you’ll get iodinated contrast for imaging. Follow your doctor’s specific instructions—holding the drug for 48 hours around those events is common practice.

Practical tips: take metformin with food to cut stomach upset, split doses if you have side effects, and consider the XR form if GI issues persist. Track your blood sugar and keep routine lab checks (kidney and possibly B12). Avoid heavy drinking while on metformin, and tell all your healthcare providers you’re taking it—especially dentists, surgeons, or those ordering scans.

Glucophage isn’t for type 1 diabetes, and it’s only part of a plan that should include diet, exercise, and regular follow-up. If you notice new symptoms, don’t guess—call your provider. Small changes like slow dose increases and regular labs make Glucophage one of the safest and most effective first-line options for managing type 2 diabetes.