Metformin

Question 1

Does Metformin cause hypoglycaemia and weight gain?

Answer 1

No.

Sulphonylureas (Gliclozide) cause does.

Question 2

What other two conditions is Metformin used in apart from T2DM?

Answer 2

1. PCOS
2. Non-alcoholic fatty liver disease.

Question 3

What is the mechanism of action of Metformin?

Answer 3

1. Increases insulin sensitivity
2. Decreases hepatic gluconeogenesis
3. Reduces gastrointestinal absorption of carbohydrates.

Question 4

What are some adverse effects of Metformin?

Answer 4

• GI upset iscommon - about 20% of patients.
• Reduced B12 absorption.
• Lactic acidosis with severe liver or renal disease (rare but common exam question.)

Question 5

What are some contraindications for using Metformin?

Answer 5

1. CKD
   
   • If creatinine >130umol/l or eGFR <45ml/min it should be reviewed.
   • Stop if >150 umol/l or eGFR <30ml/min.
2. Lactic acidosis can occur when there are periods of tissue hypoxia. (e.g. MI, sepsis, AKI, severe dehydration)
3. Iodine-containing x-ray contrast media - stop on the day of the procedure and 48 hours afterwards.
4. Alcohol abuse - a relative contraindication.