ANTIDIABETIC DRUGS: METFORMIN

Question 1

What drug class is metformin?

Answer 1

Biguanide

Question 2

MoA

Answer 2

Decreases gluconeogeneis and increases peripheral utilisation of glucose

Question 3

Dose

Answer 3

• Max dose = 2g daily
• Initial 500 build-up to 2g
• Take with or just after food

Question 4

Side effects

Answer 4

LA
Low B12 (long term)
Taste disturbance
GI
Decreased appetite - Anorexia
REPORT: muscle cramps

Question 5

When is risk of LA increased?

Answer 5

• Chronic stable HF
• Taken with drugs that can cause renal impairment (SADMAN)
• Renal impairment

Question 6

Symptoms of LA

Answer 6

• SOB
• Muscle cramps
• Abdominal pain
• Hypothermia
• Asthenia

Question 7

Dealing with GI effects with metformin

Answer 7

• increase dose slowly or give MR prep

Question 8

When should you stop taking metformin

Answer 8

AKI
dehydration
signs of LA

Question 9

Metformin - renal impairment

Answer 9

AVOID if eGFR <30 ml/min
Dose adjustment in moderate impairment (<45 ml/min)

Question 10

Metformin - monitoring

Answer 10

Renal function before + annually (every 6 months if at risk)
B12
U+Es

Question 11

Metformin + alcohol

Answer 11

hypoglycaemia

Question 12

Metformin and weight gain

Answer 12

No increase in insulin secretion, so will not cause weight gain or hypos

Question 13

Unlicensed use of metformin

Answer 13

PCOS

Question 14

Counselling points

Answer 14

Take metformin with or shortly after food or a meal
Avoid alcohol - hypo

Question 15

Interactions - hyperglycaemia

Answer 15

Prednisolone
TLD + Loop diuretics

Question 16

Metformin + HF

Answer 16

Generally, considered safe in stable HF
Not safe in acute or unstable HF