Metformin 500 mg is commonly prescribed for type 2 diabetes, but like most medications, it can cause side effects. The majority of people experience mild effects, and serious side effects are rare.
Common Side Effects[1][3][7][8]:
- Nausea or vomiting
- Diarrhea
- Stomach pain or abdominal discomfort
- Bloating or gas
- Heartburn
- Loss of appetite
- Headache
- Metallic taste in the mouth
- Feeling unusually weak or tired
- Constipation
These side effects are usually most prominent when starting the medication and often improve as your body adjusts. Taking metformin with food may help reduce stomach-related side effects[7].
Serious Side Effects[1][3][5][7] (seek immediate medical attention):
- Lactic acidosis (rare but very serious): symptoms can include extreme tiredness, muscle pain, trouble breathing, stomach pain, dizziness, slow or irregular heartbeat, and a cold feeling. This condition is more likely in people with kidney problems or other risk factors[3][7].
- Severe allergic reactions: symptoms can include swelling of the face, lips, tongue, or throat, difficulty breathing, hives, or severe rash[1].
- Other rare symptoms: confusion, drowsiness, seizures, chest pain, or severe weakness.
Additional Notes:
- Metformin generally does not cause low blood sugar (hypoglycemia) on its own but may do so when combined with other diabetes medications[7].
- If you have impaired kidney function or other significant health issues, discuss with your healthcare provider before taking metformin, as you may be at higher risk for certain side effects like lactic acidosis[6][7].
References
- [1] Metformin (Fortamet, Glumetza) – Uses, Side Effects, and More (WebMD)
- [3] Metformin Side Effects: Common and Severe – Healthline
- [5] Metformin (oral route) – Mayo Clinic
- [6] FDA SAFETY ANNOUNCEMENTS FOR METFORMIN – NCBI
- [7] How To Avoid the Side Effects of Metformin – Cleveland Clinic
- [8] Metformin: Therapeutic profile in the treatment of type 2 diabetes