Unit 10 Drugs

Question 1

Describe the MOA of furosemide

Answer 1

Loop diuretic
Small molecule
- Target = NKCC2 on tubule cells of loop of henle
- Activity = Competitive inhibitor

Physiology:

• Binds to NKCC2 transporters
• Prevents movement of Na+, K+ from luminal side to basolateral side for reabsorption
• Decreases Na+ + hence water reabsorption as water follows Na+ ( osmotically active)
• More Na+, K+, Cl- excreted into the urine

Question 2

Describe the MOA of gliclazide

Answer 2

Anti hyperglycaemic agent
Small molecule bound to plasma proteins
Target = SUR1 receptors on beta cells of islets
- Closure of ATP sensitive K+ channels
- Less K+ leaves, so depolarisation of cell
- Opens volted gated Ca2+ channels so Ca2+ influx
- Insulin released from granules to outside of cells by exocytosis

Question 3

Describe the MOA of propanolol

Answer 3

Beta blocker 
Non selective beta adrenergic receptor antaognist
- Vasoconstriction
- Apoptosis of endothelial cells
- Down regulates RAS

Question 4

Describe the MOA of atorvastatin

Answer 4

Statin
Small molecule
- Activity = reversible inhibitor of HMG coA reductase
- Inhibits conversion of HMG CoA -> mevalonate a key step in cholesterol

Physiology

• Decreases cholesterol synthesis in the liver
• Hepatocytes downregulate LDL receptors + internalise LDL
• Increased HDL + less VLDL secretion

Question 5

Describe the MOA of atorvastatin

Answer 5

Statin
Small molecule
- Activity = reversible inhibitor of HMG coA reductase
- Inhibits conversion of HMG CoA -> mevalonate a key step in cholesterol

Physiology

• Decreases cholesterol synthesis in the liver
• Hepatocytes down regulate LDL receptors + internalise LDL
• Increased HDL + less VLDL secretion

Question 6

Describe the MOA of metformin

Answer 6

Small molecule
Target = mitochondrial complex 1
activity = inhibitor
- Low ATP + high AMP
- Activation of AMPK
- Decreased gluconeogenesis in extra hepatic tissues
- Decreased absorption of glucose by increases GLP-1 ( L cells of distal gut)

Question 7

Describe the MOA carbimazole

Answer 7

Anti thyroid drug : Treatment of hyperthyroidism and thyrotoxicosis
Pro drug cleaved to active metabolite methimazole
Activity = competitive inhibitor
target = TPO

Inhibits I- addition to tyrosine units of thyroglobulin

Question 8

Describe the MOA ramipril

Answer 8

ACE inhibitor
Small molecule bound to plasma proteins
Inactive pro drug metabolised in kidneys and liver by cholinesterase’s to active metabolite ramiprilat

Target = ACE 
Activity = Reversible antagonist 

Decreased ANGII -> inhibits RAS -> lowers BP
Decreased ANGII -> less IA2 receptor stimulation of arteriole smooth muscle so less IP3
Decreased NA -> vasodilation -> lowers BP