What are the side effects of metformin?

Metformin is generally a medication used to treat diabetes, commonly available in tablets, enteric-coated tablets, sustained-release tablets, capsules, and other formulations. Its potential side effects may include gastrointestinal discomfort, metallic taste in the mouth, fatigue, allergic reactions, and lactic acidosis. A detailed explanation is as follows:

1. Gastrointestinal Discomfort

After entering the gastrointestinal tract, metformin may irritate the mucous membranes, affect normal gastrointestinal motility and digestive function. At the same time, it can also disrupt the balance of the intestinal microbiota, further exacerbating discomfort symptoms.

2. Metallic Taste in the Mouth

This symptom may be related to the metabolites of metformin in the body. These metabolites may reach the mouth through the bloodstream, affecting taste receptors and resulting in a metallic taste.

3. Fatigue

Metformin affects intracellular energy metabolism, possibly inhibiting mitochondrial respiratory chain complexes, leading to reduced cellular energy production, thereby making patients feel weak and tired. Patients often report feeling physically weak, easily fatigued, with reduced exercise tolerance, and daily activities may be somewhat affected.

4. Allergic Reaction

Some patients may be allergic to components of metformin. The immune system may recognize it as a foreign antigen, triggering an immune response that causes allergic symptoms, such as rash, itching, difficulty breathing, angioedema, and in severe cases, may even lead to anaphylactic shock.

5. Lactic Acidosis

Metformin increases anaerobic glycolysis, resulting in increased lactic acid production. If there is impaired liver or kidney function, cardiopulmonary dysfunction, or excessive alcohol consumption, it may lead to lactic acid accumulation in the body, triggering lactic acidosis. Patients may experience symptoms such as fatigue, nausea, abdominal pain, rapid breathing, and impaired consciousness.

Although metformin is an effective antidiabetic medication, it may also cause a series of side effects. Therefore, when using metformin, patients should strictly follow medical instructions for administration and closely monitor their physical condition. If any discomfort or suspected side effects occur, the medication should be stopped immediately and medical attention sought.