Side Effects Of Metformin (Glucophage)

Metformin (Glucophage) is a very commonly used medicine, and its most common side effects are stomach-related.

The FDA label and NHS guidance both note that nausea, diarrhea, abdominal discomfort, bloating, and reduced appetite are among the common side effects, especially when starting treatment or after a dose increase.

Common side effects:

• Gastrointestinal upset : Nausea, loose stools/diarrhea, stomach upset, and abdominal pain are the most frequent problems.
• Abdominal bloating – Gas, bloating, fullness, and indigestion can happen in some people.
• Metallic taste in the mouth – This is a recognized metformin side effect and is usually not dangerous, just unpleasant.
• Decreased appetite – Some people feel less hungry, especially when stomach side effects are present.
• Fatigue or weakness – This can happen, but if it is persistent, doctors may also think about vitamin B12 deficiency or another cause.
• Mild weight loss – Metformin can lead to modest weight loss in some people.
• Headache – Headache can occur, although stomach side effects are more typical.

Important long-term effect:

• Vitamin B12 deficiency – Long-term metformin use can lower B12 levels. This may cause tiredness, weakness, pale or yellowish skin, sore tongue, mouth ulcers, vision problems, or nerve symptoms if it becomes significant.

Rare but serious warning:

• Lactic acidosis – This is very rare but serious.
• FDA labeling warns it may present with symptoms such as feeling very unwell, severe weakness, stomach discomfort, breathing trouble, muscle pain, or unusual sleepiness.

Simple practical note

Metformin side effects are often worse at the beginning and may improve with time. Taking it with food and increasing the dose gradually often helps reduce stomach side effects.

When to seek medical help

• Severe or ongoing vomiting or diarrhea
• Marked weakness or worsening fatigue
• Symptoms of possible B12 deficiency
• Breathing difficulty, severe drowsiness, or feeling very sick

These need medical review, especially because rare serious reactions can be missed early.

Medical disclaimer

This note is for general education only and is not a diagnosis or personal treatment plan. Do not stop metformin on your own. If side effects are severe, persistent, or you develop symptoms suggestive of lactic acidosis or B12 deficiency, consult a qualified doctor promptly.

From: Paul S. Dangha. Bsc microbiology,MLT (amt),PT(ASCP)