MCQ's: Diabetic Drugs Flashcards
Metformin:
- Metabolised in?
Not metabolised, excreted unchanged in the urine. Undetectable in the plasma at 24 hours after a single dose.
What class of drug is metformin? What’s it’s mechanism of action?
A biguanide hypoglycaemic.
Enhances peripheral action of endogenous insulin.
Therefore decrease intestinal glucose uptake and decreases peripheral glucose utilisation.
What is metformins half life?
Time to peak concentration?
Duration of action?
6 hours.
Peak concentration at 1-3 hours.
Duration of action 8-12 hours.
True or false: Biguanides stimulate pancreatic insulin release?
False.
They decrease gluconeogenesis.
Increase glycolysis.
Decrease glucose absorption intestinally.
What type of diabetics is metformin used in?
Adult onset diabetes.
Young diabetics on insulin can precipitate ketonuria if treated with biguanides as well.
Protein binding of metformin?
Neglible protein binding.
Mechanism of action if sulfanylureas?
Increase insulin secretion but do not affect production. Bind to a receptor coupled to increase Calcium entry into pancreatic beta cells.
They displace insulin from pancreatic islet 13 cells.
Enhance insulin’s ability to glucose uptake into muscle and fat cells.
Examples of sulfanylureas?
Glibenclamide, tolbutamide, chloroproramide.
Effect on thiazides on hypoglycaemia induced by sulfanylureas?
Thiazides antagonise effect of hypoglycaemia.
haematological side effects of sulfanylureas?
Leucopenia, agranulocytosis, thrombocytopenia caused by tolbutamide and chloropropramide.
T/ F:
1. Gliclazide- protects beta cells from hyperglycaemic damage.
- Gliclazide- reduces atheromatous plaque build up.
- Chlorpropramide is metabolised and excreted by the kidney
- True
- True
- False. Chlorpropramide undergoes no significant metabolism and is excreted very slowly, largely unchanged in the urine.
Insulin pH?
pH 7, neutral insulin
True or false:
60-80% of insulin can be lost due to binding to the IV fluid container and tubing.
True
What percentage of secreted insulin is degraded and where?
80% in the liver and kidneys
Hepatic glutathione transhydrogenase breaks insulin molecule down to its constituent peptide chains.
Half life of endogenous insulin?
10-20 minutes
T/F regarding insulin:
1. It’s action involves 2nd messenger
- Polypeptide if 4 chains
- Increase cAMP in the liver
- Increase K+ uptake into cells
- Increases protein synthesis in ribosomes
- True
- False- formed of 2 chains. Alpha and beta.
- False.
- True
- True
Insulin effect on cAMP in liver?
Reduced cAMP - this actively decreases potassium in hyperkalaemia.
What hormone does insulin inhibit?
Lipase
Insulin facilitates glucose uptake into?
The pituitary, peripheral tissue (fat/ muscle), fibroblasts, liver.
Molecular form of insulin?
Molecular weight of 5600 Da
Comprised of two polypeptides alpha and beta that are strongly bound by 2 covalently bonded disulphide bridges.
Insulin can be blocked by which drug?
Atropine
What PDE inhibitor can stimulate insulin?
Theophylline
Effect of A2 and B2 agonists on insulin?
A2- decrease insulin secretion
B2- increase insulin secretion
Sulfanylureas tend to cause weight loss? T/F
False
Sulfanylureas have a shorter or longer half life than biguanides?
Longer half lives than biguanides
Which diabetic medication can cause ketonuria?
Metformin
Insulin secretion can be blocked by which drug?
Atropine
Which amino acids stimulate insulin release?
Leucine and Arginine
What hormone can inhibit insulin secretion?
Somatostatin
How does insulin affect cAMP?
Decreases cAMP in the liver
