Anticoagulants: Warfarin, Heparin, Enoxaparin

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Questions and Answers

What mechanism does warfarin use to exert its anticoagulant effect?

Direct activation of thrombin

Binding to antithrombin III

Inhibition of vitamin K epoxide reductase (VKOR1) (correct)

Inhibition of factor 10 alone

Which of the following agents is used as a reversal agent for heparin?

Idarucizumab

Aspirin

Andexanet alfa

Protamine sulfate (correct)

What is the primary action of enoxaparin?

Binding to vitamin K

Inactivation of factor 10 (correct)

Directly inhibiting thrombin

Inhibition of factor 2

Which anticoagulant can cause skin necrosis?

Warfarin Signup and view all the answers

Which of the following statements about rivaroxaban is incorrect?

It can be reversed with protamine sulfate. Signup and view all the answers

What is the primary role of cilostazol?

Intermittent claudication treatment Signup and view all the answers

What distinguishes dabigatran from other anticoagulants?

It is a direct thrombin inhibitor and a prodrug. Signup and view all the answers

Which antiplatelet drug irreversibly binds to the P2Y12 ADP receptor?

Clopidogrel Signup and view all the answers

What is the primary adverse effect associated with thrombolytics like alteplase?

Severe bleeding complications Signup and view all the answers

What is the main action of statins?

Inhibiting de novo cholesterol synthesis Signup and view all the answers

Which of the following uses increase LDL clearance primarily via the LDL receptor?

Statins Signup and view all the answers

What is the primary effect of niacin in lipid management?

Reduce LDL and increase HDL Signup and view all the answers

Which combination of medications is indicated for elevated triglycerides?

Niacin and fibrates Signup and view all the answers

Which class of drugs primarily prevents the conversion of angiotensinogen to angiotensin I?

Renin inhibitors Signup and view all the answers

Which beta-blocker is non-selective and affects both beta1 and beta2 receptors?

Propranolol Signup and view all the answers

Which class of medications is most effective for lowering serum triglycerides and increasing HDL levels?

Fibrates Signup and view all the answers

What adverse effect is commonly associated with ACE inhibitors?

Dry cough Signup and view all the answers

Which medication is a selective blocker of beta1 receptors and often prescribed for hypertension?

Atenolol Signup and view all the answers

What mechanism do bile acid sequestrants primarily use to lower LDL cholesterol?

Bile acids excretion leading to increased cholesterol conversion Signup and view all the answers

Which drug class decreases blood pressure by limiting intracellular calcium levels?

Calcium channel blockers Signup and view all the answers

Study Notes

Warfarin

Vitamin K antagonist
Inhibits factors 2, 7, 9, and 10
Inhibits VKOR1
Reduces clotting factors due to lack of gamma-carboxylglutamyl side chains
Used for prosthetic heart valves
Requires bridging drugs (heparin or enoxaparin) initially due to hypercoagulability
Reversal: Vitamin K + 4F-PCC or FFP (non-life threatening)
Contraindicated in pregnancy
INR target range 2-3
Oral administration

Heparin

Highly acidic
Binds to antithrombin III via pentasaccharide complex
Inactivates factors 2 and 10
Subcutaneous or IV administration (prophylaxis)
Adverse effects: bleeding, Heparin-induced thrombocytopenia (HIT)

Enoxaparin

Low-molecular-weight heparin (LMWH)
Binds to antithrombin III via pentasaccharide complex
Inactivates factor 10
Subcutaneous injections
Adverse effects: bleeding, HIT (greater risk than heparin)
Protamine sulfate is used for reversal (partially effective for enoxaparin)

Fondaparinux

Pentasaccharide
Inhibits factor 10 via antithrombin III
Injectable
Contraindicated in renal disease
No reversal agent

Rivaroxaban and Apixaban

Direct factor 10 inhibitors
Oral tablets
Contraindicated in renal disease
Reversal agents exist (andexant alfa for rivaroxaban)

Dabigatran

Direct thrombin inhibitor
Oral prodrug
Contraindicated in renal disease
Reversal agent (idarucizumab)

Other Drugs

Bivalirudin and argatroban: direct thrombin inhibitors
Alteplase: thrombolytic (for acute ischemic stroke)
Aspirin: COX inhibitor (acetylation of a serine residue on COX, reduces TxA2, GI bleeding and ulcer risk)
Clopidogrel andticagrelor: P2Y12 ADP receptor inhibitors
Abciximab and eptifibatide: GPIIb/IIIa inhibitors
Cilostazol: PDE3 inhibitor (inhibition of PDE3 resulting in decreased catabolism of cAMP)
Statins: HMG-CoA reductase inhibitors

Cholesterol-Lowering Drugs

Competitive inhibitors (inhibiting de novo synthesis, deplete intracellular supply of cholesterol, plaque stabilization, improvement of coronary endothelial function)
Statins: reduce LDL cholesterol principally by increasing LDL clearance via the LDL receptor
Nicotinic acid (niacin): strongly inhibits lipolysis, reduce VLDL and LDL, increase HDL
Fibric acid derivatives (fibrates): increase HDL levels, reduce triglycerides
Bile acid sequestrants: bind bile acids and bile salts in the small intestine, increase LDL receptors
Ezetimibe: selectively inhibits cholesterol absorption in the small intestine

Other Information

Adverse effects are mentioned for many of the drugs, including bleeding and other complications.
Contraindications are discussed for certain conditions (e.g., renal disease)
Reversal agents/alternatives are mentioned where applicable.

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Description

Test your knowledge on anticoagulants including Warfarin, Heparin, and Enoxaparin. This quiz covers their mechanisms, uses, contraindications, and reversal strategies. Perfect for students in pharmacology or medicine.