Pharmacology: Metformin

Question 1

what type of compound is metformin

Answer 1

biguanide

Question 2

what is the mechanism of metformin

Answer 2

inhibition of complex 1 of the mitochondrial respiratory chain(electron chain)

Question 3

what is the main action of metformin

Answer 3

results in fall in cellular ATP(rise in ADP/ATP ratio)

Question 4

what are some of the consequences of metformin

Answer 4

rise in AMP:ATP, activation of AMPK, reduction in gluconeogenesis

Question 5

is metformin hydrophobic or philic

Answer 5

hydrophilic

Question 6

how does meformin enter cells

Answer 6

requires active transport by Organic Cation Transporters(OCTs)

Question 7

where are Organic Cation Transporters(OCTs) present in the body

Answer 7

intestines, liver, kidney

Question 8

what is the main mechanism of metformin in the gut

Answer 8

increases glucose utilisation and metabolism

Question 9

what is the main mechanism of metformin in the liver

Answer 9

lowers hepatic glucose production(in people with poorly controlled diabetes)

Question 10

is metformin an insulin sensitiser

Answer 10

no, doesn’t increase tissue sensitivity to insulin

Question 11

does metformin affect weight

Answer 11

no

Question 12

what is the clinical use of metformin in diabetes patients

Answer 12

lowers blood glucose levels

Question 13

what is the usual dose of metformin

Answer 13

500mg bd
(max dose is 1g)

Question 14

what are the side effects of metformin

Answer 14

GI intolerance(eg diarrhoea, pain, metallic taste in mouth), Metformin Associated Lactic Acidosis(MALA)

Question 15

describe how GI intolerance effects those taking metformin and how to reduce this side effect

Answer 15

1 in 5 get this side effect, 1 in 20 need to stop due to this side effect
Initiate on lower dose slowly

Question 16

how should metformin dose be changed in relation to renal function

Answer 16

metformin should be decreased as renal function falls

Question 17

what effect can metformin have in those with acute kidney injury or sepsis

Answer 17

associated with increased risk of MALA(metformin associated lactic acidosis)

Question 18

describe where metformin fits into diabetes treatment plan

Answer 18

first line therapy