Metformin 500mg: Uses, Dosage and Side Effects

Metformin hydrochloride (Tablet, Biguanide antidiabetic) - First-line tablet for type 2 diabetes; lowers blood sugar without usually causing hypos.

Overview

Metformin is usually the first medicine prescribed for type 2 diabetes. It lowers blood sugar, does not usually cause weight gain and rarely causes hypoglycaemia on its own. It is also used in some people with prediabetes or polycystic ovary syndrome on specialist advice.

How It Works

Metformin reduces glucose production by the liver and improves the body's sensitivity to insulin.

Uses (Indications)

• Type 2 diabetes
• Prediabetes in selected people
• Polycystic ovary syndrome (specialist use)

Dosage: General Label Information

Contraindications: Who Should Not Take It

• Severe kidney impairment
• Conditions causing low oxygen or severe dehydration
• Before some contrast X-rays or surgery (may be paused)
• Heavy alcohol use

Side Effects

• Nausea, diarrhoea, stomach upset (often improves)
• Metallic taste
• Low vitamin B12 with long use
• Lactic acidosis (rare but serious)

Interactions

• Iodinated contrast dye
• Alcohol
• Some diuretics and steroids

Storage

Store below 25°C.

Patient Counselling Tips

• Take with meals
• Pause on sick days with vomiting or diarrhoea if advised
• Have kidney tests yearly

When to See a Doctor

• Severe vomiting, fast breathing or muscle pain (possible lactic acidosis)
• Ongoing stomach upset

Before You Take Metformin 500mg

Tell your doctor or pharmacist if you are pregnant or breastfeeding, have kidney, liver or heart problems, have had an allergic reaction to any medicine, or take other prescription medicines, herbal remedies or supplements. Bring a list of everything you take to every appointment.

Missed Doses and Long-Term Use

If you miss a dose of Metformin 500mg, take it when you remember unless it is almost time for the next one; never double up. Long-term medicines work best when taken at the same time every day. Do not stop suddenly without talking to your prescriber, and keep follow-up appointments and blood tests.

Frequently Asked Questions

This Metformin 500mg guide is educational, based on official labelling and public guidance, and reviewed by the ghkh.site editorial team. Always read the leaflet in your pack and ask your pharmacist.