Metformin – First-line diabetes medication for blood sugar control.
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What is Metformin?
Metformin is the cornerstone of type 2 diabetes treatment and one of the most prescribed medications worldwide. Its proven effectiveness in controlling blood sugar, promoting weight loss, and providing cardiovascular protection makes it the preferred first-line treatment for type 2 diabetes.
Book an online consultation if you have been diagnosed with type 2 diabetes, prediabetes, or PCOS, or if you need assessment for diabetes risk factors. Our GPs can evaluate your blood sugar control and determine if Metformin or other diabetes treatments are appropriate for your specific condition.
What is Metformin used for?
- Type 2 diabetes mellitus
- Prediabetes (impaired glucose tolerance)
- Polycystic ovary syndrome (PCOS)
- Weight management in diabetes
- Insulin resistance syndrome
- Prevention of diabetes in high-risk individuals
How does Metformin work?
A biguanide that reduces glucose production by the liver, increases insulin sensitivity in muscles, and slows glucose absorption from the intestines, lowering blood sugar without causing hypoglycemia.
Dosage and Administration
Adults
Starting dose 500mg once or twice daily with meals. Gradually increased to 1000-2000mg daily in divided doses. Maximum 3000mg daily.
Children
Children over 10 years: starting dose 500mg twice daily—specialist supervision required.
Important Notes
- Always take with or after food to reduce stomach upset.
- Start with low dose and increase gradually over weeks.
- Extended-release formulations taken once daily with evening meal.
- Regular blood sugar and kidney function monitoring required.
Side Effects
Common Side Effects
- Nausea and vomiting
- Diarrhoea
- Stomach upset and cramping
- Metallic taste
- Loss of appetite
- Weight loss (often beneficial)
Serious Side Effects
Seek immediate medical attention if you experience:
- Lactic acidosis (rare but serious)
- Vitamin B12 deficiency (with long-term use)
- Kidney problems
- Severe allergic reactions
- Liver problems (rare)
Important Warnings
- Tell your GP if you have kidney disease, liver problems, or heart failure.
- Stop before surgery, X-rays with contrast, or if you become seriously ill.
- Seek immediate medical attention if you develop severe weakness, muscle pain, or breathing difficulties (signs of lactic acidosis).
- Regular monitoring of kidney function and vitamin B12 levels needed.
- Avoid excessive alcohol consumption.
Drug Interactions
Tell your GP if you're taking any of the following medications:
- Contrast dyes—stop metformin before procedures, restart when kidney function confirmed normal.
- Alcohol—increases risk of lactic acidosis.
- Steroids—may reduce effectiveness by raising blood sugar.
- Diuretics—may affect kidney function and increase metformin levels.
- ACE inhibitors—may increase risk of lactic acidosis in kidney disease.
Frequently Asked Questions
Why is Metformin the first choice for type 2 diabetes?
Metformin is highly effective, doesn't cause hypoglycemia, often promotes weight loss, has cardiovascular benefits, and has an excellent long-term safety record.
Will Metformin help me lose weight?
Many people lose 2-5kg on Metformin due to reduced appetite and improved metabolism, though weight loss varies between individuals.
Can I take Metformin if I have kidney problems?
Metformin dose must be reduced or stopped if kidney function is impaired, as reduced kidney function increases the risk of lactic acidosis.
How long does it take to work?
Blood sugar improvements are usually seen within days to weeks, but full benefits may take 2-3 months as the dose is optimized.
Medically Reviewed by: Mohammed Hassan - Independent Prescriber
Last Updated: 2025-01-14