3.1 + 3.2 Insulin and Other Hypoglycaemic Agents Flashcards
Give 3 reasons why diabetes is a strain on the NHS
Lots of diagnosed cases
Many complications arise
Need regular check ups
Growing problem due to increased obesity
Why does blood glucose rise in a Type 1 diabetic?
Lack of insulin due to autoimmune damage of the pancreas
Why does blood sugar rise in a Type 2 diabetic?
Lack of production of insulin and a reduced sensitivity to insulin
What is the normal range of glucose concentration in the blood?
3.8-6.5 mmol/L
What is the first stage of treatment for a Type II diabetic?
Exercise
Healthy diet
Smoking cessation
Reduced alcohol
What type of drug is Metformin?
Biguanide
What is the mechanism of metformin?
Increases sensitivity of cells to insulin
Enhances skeletal and adipose tissue glucose uptake
Inhibits hepatic gluconeogenesis
When is metformin ideally taken?
Prior to meals
2-3 times a day
What ADRs are common with Metformin?
GI disturbances eg. diarrhoea
When should Metformin not be given to a patient?
GFR <30ml/min
Suffering from heart, liver or respiratory disease
What is the mechanism of action of a Thiazolidinedione?
Bind to a nuclear hormone receptor site (PPAR-y)
Binds to another nuclear receptor (RXR)
PPAR-y/RXR complex then upregulates genes which control insulin signalling
What ADRs are common with Thiazolidinediones?
Weight gain
Osteoporosis
Increases LDLs and VLDLs
Increased risk of bladder cancer
Give an example of a sulphonylurea?
Glipizide
Gliclazide
What is the mechanism of action of a sulphonylurea?
Antagonise K+-ATPase channels in B cells in the pancreas.
Less K+ results in depolarisation and therefore increased Ca2+ entry into a cell
More insulin containing vesicles fuse with the membrane and are released into the bloodstream
What ADRs are common with sulphonylureas?
Risk of hypoglycaemia leading to diabetic coma
Weight gain
GI disturbances
What is the mechanism of action of Acarbose?
Give 2 common ADRs
Inhibits alpha glucosidase so carbohydrates cannot be broken down
ADRs: flatulence and diarrhoea
What is the mechanism of action of Glifozins?
Give 2 common ADRs
Stop kidney from reabsorbing glucose by blocking glucose reabsorption channels in the PCT
ADRs: polyuria, increased risk of UTIs
List the 6 types of insulin analogues
Bovine or porcine insulin
Rapid-acting insulin Short-acting insulin Intermediate insulin Long-acting insulin Very long-acting insulin
Why is a patient given a mixture of insulins to treat diabetes?
Giving various acting insulins allows a more realistic blood sugar control.
Short-acting given before meals
Long-acting given overnight
Give 3 factors that may cause blood glucose control to vary
Stress
Exercise
Over/under eating
What is Type 2 combination theory?
Start with exercise and diet Move to Metformin HbA1c >7% --> sulphonylurea added HbA1c >7.5% --> start insulin therapy If HbA1c continues to rise the insulin dose is titrated upwards
Give some ADRs of insulin
Hyperglycaemia Hypoglycaemia Lipodystrophy Painful injections Insulin allergies
Explain why sulphonylureas may cause DDIs
Binds heavily to plasma proteins so may displace other drugs in the body and force the competing drug above the therapeutic window.
Describe the mechanism of action of the anti-obesity drug Orlistat
Gastric and pancreatic lipase inhibitor
Reduces dietary fat conversion to fatty acids and glycerol
Give 3 side effects of the anti-obesity drug Orlistat
Soft fatty stools
Flatulence
Faecal incontinence
How does the anti-obesity drug Sibutramine work?
Noradrenaline and serotonin re-uptake inhibitor
Suppresses appetite and increases glucose metabolism
