SBI242 Week 6 - Pharmacology of the Cardiovascular System part 2

What are the primary functions of the kidney?

All of the above

What is the functional unit of the kidney?

Nephron

What is the normal glomerular filtration rate (GFR)?

125 mL/min, or 180 L of filtrate formed per day

What is the mechanism of action of diuretic drugs?

Modify renal function to induce diuresis and natriuresis by inhibiting reabsorption of sodium and chloride in the nephron

What are four classes of diuretic drugs?

Loop diuretics, Thiazide diuretics, Potassium-sparing diuretics, Osmotic diuretics

How do osmotic diuretics work?

Creating an osmotic gradient that inhibits water reabsorption in the renal tubules

How do loop diuretics work?

Inhibiting sodium-potassium-chloride cotransporter in the thick ascending limb of the loop of Henle

How do thiazide diuretics work?

Inhibiting sodium-chloride cotransporter in the distal convoluted tubule

How do potassium-sparing diuretics work?

Blocking aldosterone receptors or inhibiting sodium channels in the collecting duct

What is the mechanism of action of beta-blocker drugs?

Blocking beta-adrenergic receptors, reducing sympathetic nervous system activity

What are the therapeutic cardiovascular effects of beta-blockers?

Decrease heart rate, conduction velocity, myocardial contractility, and cardiac output

What is dyslipidemia?

A metabolic disorder characterized by increased concentrations of lipids and lipoproteins

How are lipids transported in the bloodstream?

Bound to lipoproteins

Name three primary lipoproteins found in the blood.

LDL (Low-Density Lipoprotein), HDL (High-Density Lipoprotein), VLDL (Very Low-Density Lipoprotein)

What is the function of LDL cholesterol and why is it considered 'bad' cholesterol?

LDL transports cholesterol from the liver to peripheral tissues, and high levels can lead to atherosclerosis

What is the function of HDL cholesterol and why is it considered 'good' cholesterol?

HDL carries cholesterol from the periphery back to the liver, preventing accumulation of cholesterol in arterial walls

What is the mechanism of action of HMG-CoA reductase inhibitors (statins)?

Inhibiting HMG-CoA reductase, reducing cholesterol synthesis in the liver

How do PCSK9 inhibitors work?

Blocking PCSK9-mediated degradation of LDL receptors, increasing LDL clearance

Bile acid-binding resins work by:

Binding to bile acids in the gut, increasing their excretion and reducing cholesterol levels

How do fibrates work?

Interact with peroxisome proliferator-activated receptors (PPARs) to reduce triglyceride concentration via stimulation of fatty acid oxidation and increased LPL activity

What are the three sequential steps of the hemostatic mechanism?

Vasoconstriction, platelet plug formation, coagulation

What is the role of prostacyclin (PGI2) in limiting the spread of thrombus?

Inhibits secretion of mediators from platelets and platelet aggregation, and causes vasodilation

Three types of thrombi are:

Arterial thrombus, Venous thrombus, Mural thrombus

The final common pathway in the intrinsic and extrinsic coagulation pathways is:

Activation of factor X, leading to the conversion of prothrombin to thrombin

How do low-molecular-weight heparins (LMWHs) work?

Enhancing antithrombin III's inhibition of factor Xa more than thrombin

How do vitamin K antagonists (e.g., warfarin) work?

Interfere with hepatic synthesis of vitamin K-dependent clotting factors by inhibiting vitamin K epoxide reductase complex 1 (VKORC1)

How do direct factor Xa inhibitors (e.g., rivaroxaban, apixaban) work?

Inhibiting the conversion of prothrombin to thrombin by blocking factor Xa

Aspirin acts as an antiplatelet drug by:

Irreversibly inhibiting cyclooxygenase-1 (COX-1), reducing thromboxane A2 synthesis

How do P2Y12 inhibitors (e.g., clopidogrel, prasugrel, ticagrelor) work?

Blocking the P2Y12 component of ADP receptors on platelets, inhibiting platelet activation and aggregation

Glycoprotein IIb/IIIa receptor inhibitors work by:

Blocking platelet aggregation by inhibiting fibrinogen binding to glycoprotein IIb/IIIa receptors

Direct thrombin inhibitors work by:

Directly binding to and inhibiting thrombin

Thrombolytic drugs work by:

Activating plasminogen to plasmin, which breaks down fibrin clots

Tranexamic acid works by:

Inhibiting plasminogen activation and subsequent plasmin formation

Functions of the kidney include all of the following EXCEPT:

Releases aldosterone in response to low arterial blood pressure

Diuretics are indicated for which of the following conditions?

Hypertension

The mechanism of action of diuretics is to:

Inhibit the reabsorption of sodium and calcium in the nephron

Frusemide exerts its action in which part of the nephron tubule?

Loop of henle

Loop diuretics are associated with which of the following side effects?

Hypokalaemia

The mechanism of action of beta-blocker drugs is to:

Competitively block β-cholinergic sites on cardiac and smooth muscle

A 55 yr old male is diagnosed with coronary heart disease after suffering a myocardial
infarction (MI). He is prescribed a beta-blocker as prophylaxis for MI. The male also suffers
from moderate Asthma. Which of the following beta-blockers would be most suitable for
this patient?

Atenolol

Atherosclerosis characterised by:

Cholesterol deposits in the arterial wall, which eventually produce degenerative
changes and obstruct blood flow

A 40 yr old female is diagnosed with hypercholesterolemia. Her doctor recommends a
diet that will help reduce her cholesterol level prior to considering medication. The diet
aims to:

Increase her high-density lipoprotein level, and decrease her low-density lipoprotein
level

A 40-year-old female returns to her doctor after 4 months of a strict diet and exercise regime. Her blood tests still indicate a high blood-cholesterol level. Her doctor decides to prescribe her medication to help lower her cholesterol level. He prescribes a ‘statin’. This medication acts by:

Inhibiting the conversion of HMG-CoA to mevalonate, which is an essential precursor
in the synthesis of cholesterol

What are the clotting factors involved in the intrinsic coagulation pathway?

Factor XII (activated to XIIa), factor XI (Xia) and factor IX (IXa)

The mechanism of action of low molecular weight heparin is to:

Inactivate factor Xa

Aspirin acts as an anti-platelet agent by:

Inhibiting the COX-1 necessary for thromboxane A2 synthesis thus suppressing
platelet aggregation

Tenecteplase is a thrombolytic drug. Its mechanism of action is to:

Converts blood plasminogen to plasmin

Bill is a 70 year old patient who was recently prescribed an antibiotic (erythromycin)
for an upper respiratory tract infection. Just over a year ago Bill suffered a
myocardial infarction and is also taking some medications for MI prophylaxis
including an ACE inhibitor, Aspirin and Atorvastatin to maintain a healthy cholesterol
level. Bill recently started to experience significant muscle pain. Bill’s doctor rules
out physical injury and starts to suspect one of his drugs could be responsible. Which
one of Bill’s medications could be responsible for this muscle pain?

Atorvastatin

A patient suffering from left-sided heart failure is prescribed a beta-blocker drug as prophylaxis. What effect will the beta blocker have on preload?

The beta blocker will reduce heart rate, thus allowing more end-diastolic filling time, resulting in increased preload and improved cardiac output

Why is it not recommended to prescibe a non-selective beta-blocker drug to a patient with asthma?

The non-selective beta-blocker drug also acts on Beta 2 receptors in the bronchioles causing bronchoconstriction and exacerbation of asthma

A diabetic patient is prescribed a diuretic to treat his high blood pressure. What is the concern with a diabetic patient taking a diuretic?

It could precitipate hyperglycaemia

What is the mechanism of action of aspirin as an anti-platelet agent?

Inhibits COX-1 necessary for thromboxane A2 synthesis, thus suppressing platelet-aggregation

What would stimulation of adrenergenic beta 2 receptors produce?

Arterial vasodilation

A 59 year-old male patient is prescribed with the following medications: a beta-blocker, a loop diuretic, and an ACE inhibitor for his hypertension. After a month of taking these medications, the patient complains to his doctor that he often feels tired, dizzy and has fainted on several occasions. Which of the following would be the most likely side effect of these combined medications?

Hypotension

A patient who has recently suffered an MI was prescribed a beta-blocker medication as prophylaxis. The patient also suffers from asthma and is taking asthma medication. What is the potential adverse drug reaction for an asthmatic patient taking beta-blockers?

The beta-blocker can cause bronchoconstriction of the bronchiole smooth muscle