Y1S2 004 I Pharmacology Cardiovascular: Medications and Mechanisms

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Questions and Answers

What is the effect of Propranolol on heart rate?

It initially increases then decreases heart rate

It increases heart rate

It has no effect on heart rate

It decreases heart rate (correct)

What is the mechanism of action of Nitroglycerin?

It increases heart rate by stimulating the beta receptors

It inhibits smooth muscle contraction by releasing nitric oxide (correct)

It relaxes smooth muscle by increasing calcium influx

It constricts blood vessels by increasing blood pressure

What is the main adverse effect of Propranolol?

Increased heart rate

Increased blood pressure

Cardiac failure

Bronchi-constriction (correct)

What is the route of administration of Propranolol?

Oral Signup and view all the answers

What is the effect of Nitroglycerin on blood pressure?

It decreases blood pressure Signup and view all the answers

What is the half-life of Propranolol?

4 hours Signup and view all the answers

What is the main effect of digoxin on the heart?

Increases the force of contraction of the heart Signup and view all the answers

What is the mechanism of action of digoxin?

It inhibits the Na+/K+ ATPase pump Signup and view all the answers

What is the therapeutic use of digoxin?

Treatment of congestive cardiac failure Signup and view all the answers

What is the effect of aspirin on platelet function?

It prevents platelet activation and aggregation Signup and view all the answers

What is the primary reason for using low-dose aspirin?

Inhibition of PGI2 formation in endothelium Signup and view all the answers

What is the mechanism of action of heparins?

Inhibition of coagulation cascade Signup and view all the answers

What is the mechanism of action of aspirin?

It inhibits the cyclooxygenase enzyme Signup and view all the answers

What is the antidote for heparin overdose?

Protamine sulphate Signup and view all the answers

What is the duration of action of aspirin on platelets?

7-10 days Signup and view all the answers

What is the primary mechanism of action of warfarin?

Prevention of vitamin K synthesis Signup and view all the answers

What is the consequence of warfarin-induced skin necrosis?

Death Signup and view all the answers

What is the typical incidence of thrombosis in heparin-induced thrombocytopenia?

30-50% Signup and view all the answers

Study Notes

Cardiovascular Drugs

Beta Blockers - Propranolol

Non-selective β-antagonist, used to treat angina, hypertension, arrhythmias, and glaucoma
Inhibits contraction of the heart by blocking β1 receptors, reducing heart rate and force of contraction
Adverse effects: bronchi-constriction, cardiac failure, fatigue, and depression
Route of administration: oral, with a half-life of 4 hours and high first-pass metabolism

Vasodilators - Nitroglycerin

Dilates blood vessels, reducing blood pressure and workload on the heart
Converted to nitric oxide (NO) by mitochondrial aldehyde dehydrogenase (MtALDH)
Route of administration: intravenous, sublingual, with a peak concentration time of approximately 4.4 minutes
Adverse effects: hypotension, vertigo, flushed skin, diaphoresis, fever, syncope, dyspnea, and bradycardia

Cardiac Glycosides - Digitalis (Digoxin)

Increases force of contraction of the heart, used to treat congestive cardiac failure (CCF)
Extracted from the foxglove plant (Digitalis spp.), with digoxin being the main drug in this class
Acts on the heart, increasing intracellular Ca²⁺ concentrations, which leads to increased force of contraction
Adverse effects: arrhythmia (tachycardia, atrioventricular block), hypokalemia, abdominal discomfort, nausea, and vomiting
Route of administration: oral or intravenous, with a half-life of 36-40 hours

Antiplatelets - Aspirin

Prevents clotting of blood by inhibiting the synthesis of thromboxane A2 (TXA2) in platelets
Irreversible inhibition of cyclooxygenase (COX) enzyme, specifically COX 1 in platelets
Route of administration: oral, with a dose of 160-320 mg/d, and a duration of 7-9 days
Adverse effects: GIT irritation, and used at low doses to prevent platelet aggregation

Anticoagulants - Heparin and Low Molecular Weight Heparin (LMWH)

Prevent clotting of blood by inactivating clotting factors IIa, IXa, Xa, XIa, and XIIa
Inhibit coagulation cascade, preventing fibrin formation and blood clotting
Route of administration: intravenous, subcutaneous, with a low therapeutic index
Adverse effects: osteoporosis, hyperkalemia, hypersensitivity reactions, and heparin-induced thrombocytopenia

Anticoagulants - Warfarin

Inhibits blood clot formation by preventing the synthesis of clotting factors II, VII, IX, and X
Structurally related to vitamin K, with a slow onset of 48 hours and a peak anticoagulant effect at 72-96 hours
Route of administration: oral, with a half-life of 25-60 hours, and a high plasma protein binding of 99%
Adverse effects: diarrhea, bleeding, warfarin-induced skin necrosis, and a low therapeutic index
Monitored using prothrombin time (PT) and international normalized ratio (INR)

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Description

Test your knowledge of cardiovascular drugs, including their mechanisms of action and effects on the heart and blood vessels. This quiz covers a range of medications, from beta blockers to anticoagulants, and their roles in managing cardiovascular health.