Y1S2 004 III Pharmacology Cardiovascular Drugs: Mechanisms and Actions

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Questions and Answers

What is the effect of propranolol on the heart rate?

Increases it

Has no effect on it

Decreases it (correct)

Initially increases it then decreases it

Which of the following is NOT a use of propranolol?

Angina

Asthma (correct)

Hypertension

Arrhythmias

What is the mechanism of action of nitroglycerin?

It increases the contraction of the heart

It dilates blood vessels (correct)

It increases the clotting of blood

It inhibits the contraction of the heart

What is the effect of digitalis on the heart?

It increases the stroke volume Signup and view all the answers

What is the half-life of propranolol?

4 hours Signup and view all the answers

What is the enzyme responsible for converting nitroglycerin to nitric oxide?

Mitochondrial aldehyde dehydrogenase (MtALDH) Signup and view all the answers

What is the primary effect of digoxin on the heart muscles?

Increases the force of contraction Signup and view all the answers

What is the mechanism of action of digoxin in the heart?

Binds to the Na+/K+ ATPase pump and increases intracellular sodium Signup and view all the answers

What is the effect of digoxin on the pumping action of the ventricles in congestive cardiac failure?

Increases the pumping action of the ventricles Signup and view all the answers

What is the half-life of digoxin?

36-40 hours Signup and view all the answers

What is the mechanism of action of aspirin as an antiplatelet agent?

Irreversible inhibition of cyclooxygenase (COX) enzyme Signup and view all the answers

Why does the effect of aspirin on platelets last for 7-10 days?

Because platelets cannot synthesize new proteins Signup and view all the answers

What is the primary reason for using low-dose aspirin in preventing ischemic stroke and MI?

To prevent platelet aggregation Signup and view all the answers

Which of the following clotting factors is NOT inactivated by heparin?

Factor VIII Signup and view all the answers

What is the primary mechanism of action of warfarin?

Preventing the synthesis of clotting factors Signup and view all the answers

What is the primary adverse effect of heparin that is associated with a high incidence of thrombosis and amputations?

Heparin-induced thrombocytopenia (HIT) Signup and view all the answers

What is the primary method of monitoring warfarin therapy?

Prothrombin time (PT) and international normalized ratio (INR) Signup and view all the answers

What is the primary treatment for warfarin-induced skin necrosis?

Heparin administration Signup and view all the answers

Study Notes

Propranolol and Heart Rate

Propranolol is a beta-blocker that reduces heart rate by antagonizing beta-adrenergic receptors.
Common uses include treating hypertension, anxiety, and migraines.

Uses of Propranolol

Not typically used as a primary treatment for asthma due to potential bronchoconstriction effects.

Nitroglycerin Mechanism of Action

Nitroglycerin works by converting to nitric oxide, leading to vasodilation of blood vessels and decreased myocardial oxygen demand.

Digitalis and Heart Function

Digitalis positively inotropes the heart, increasing the force of ventricular contraction.
It helps manage heart failure and arrhythmias by enhancing cardiac output.

Propranolol Half-Life

The half-life of propranolol is approximately 3 to 6 hours.

Nitroglycerin Conversion Enzyme

The enzyme responsible for converting nitroglycerin to nitric oxide is mitochondrial aldehyde dehydrogenase.

Digoxin Effects on Heart Muscle

Digoxin enhances the contractility of heart muscle, supporting more effective pumping.

Mechanism of Action of Digoxin

Digoxin inhibits the Na+/K+-ATPase pump, increasing intracellular sodium and calcium, which strengthens heart contractions.

Digoxin in Congestive Cardiac Failure

In congestive heart failure, digoxin improves the pumping action of ventricles, reducing symptoms of fatigue and shortness of breath.

Digoxin Half-Life

Digoxin has a half-life of about 36 to 48 hours, requiring careful monitoring for toxicity.

Aspirin as an Antiplatelet Agent

Aspirin inhibits cyclooxygenase-1 (COX-1), preventing the formation of thromboxane A2, which is essential for platelet aggregation.

Duration of Aspirin's Antiplatelet Effect

Aspirin’s effect on platelets lasts 7-10 days due to irreversible inhibition of COX-1 in platelets.

Low-Dose Aspirin Benefits

Low-dose aspirin is used to prevent ischemic stroke and myocardial infarction (MI) by reducing clot formation.

Clotting Factors and Heparin

Heparin does not inactivate factor VII, which is essential for the extrinsic coagulation pathway.

Warfarin Mechanism of Action

Warfarin works by inhibiting vitamin K epoxide reductase, affecting the synthesis of vitamin K-dependent clotting factors.

Heparin Adverse Effects

Heparin can induce thrombocytopenia, leading to a paradoxical increased risk of thrombosis and potential amputations.

Monitoring Warfarin Therapy

Prothrombin time (PT) and INR (International Normalized Ratio) are used as standard measures for monitoring warfarin therapy.

Warfarin-Induced Skin Necrosis Treatment

The primary treatment for warfarin-induced skin necrosis includes discontinuing warfarin and administering vitamin K.

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Description

This quiz covers the mechanisms and actions of various cardiovascular drugs, including propranolol, nitroglycerin, digitalis, aspirin, heparin, and warfarin. Learn about their effects on heart rate, blood vessels, and blood clotting. Test your knowledge of these important medications!