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• Unit 6 focuses on antihyperlipidemics, vasodilators, anticoagulants, antiplatelets, and thrombolytics.

Thrombus Formation and Pathophysiology

• Thrombus formation can occur in either arteries or veins due to decreased circulation, platelet aggregation on vessel walls, and blood coagulation.
• Arterial clots form when platelets initiate the process, leading to fibrin formation.
• Red blood cells become trapped in the fibrin mesh during clot formation.
• Venous clot formation involves platelet aggregation with fibrin, which then attaches to RBCs.

Drugs for Maintaining and Restoring Circulation

• Antiplatelets prevent platelet aggregation; examples include aspirin and clopidogrel.
• Anticoagulants prevent clot formation that inhibits circulation; examples include warfarin, heparin, and enoxaparin.
• Thrombolytics attack and dissolve already formed blood clots; an example is alteplase.

Antiplatelet Drugs: Aspirin

• Aspirin is an effective and inexpensive treatment for suppressing platelet aggregation.
• Low-dose aspirin therapy inhibits platelet aggregation by inhibiting COX 1.
• Used for the prevention of MI and stroke,
• Refer to unit 2 for a comprehensive aspirin review.

Antiplatelet Drugs: Clopidogrel Bisulfate

• Clopidogrel bisulfate suppresses platelet aggregation
• Used to prevent thrombosis in arteries, myocardial infarction, stroke in clients with familial history, repeat myocardial infarction, and stroke in clients having transient ischemic attacks.
• Side effects of clopidogrel include abdominal pain, bleeding, and hypotension.
• Bleeding and peptic ulcers are contraindications
• Caution must be exercised with liver and renal disease.
• Interacts with other drugs that cause bleeding and the "5 Gs": ginger, garlic, ginseng, ginko biloba, and green tea.

Oral Anticoagulants: Warfarin

• Warfarin inhibits the hepatic synthesis of vitamin K, affecting clotting factors II, VII, IX, and X.
• Used to prevent and treat blood clotting, including DVT, pulmonary embolism, and stroke.
• PT and INR are used to monitor the therapeutic range - an INR value between 2 and 3 is the target.
• Vitamin K is the antidote for warfarin overdose; its effects take 24-48 hours.
• Fresh frozen plasma or platelets are indicated for acute bleeding
• Contraindications include blood dyscrasias, alcoholism, and head trauma.
• Caution must be exercised with diabetes mellitus; can lower blood glucose.
• Warfarin interacts with drugs and herbs that cause bleeding and many other mediations that increase its effect.
• A consistent intake of vitamin K foods should be maintained.

Oral Anticoagulants: Apixaban

• Apixaban selectively blocks the activity of clotting factor Xa to prevent clot formation.
• Used to prevent and treat DVT, PE, stroke, and atrial fibrillation.
• Routine coagulation monitoring is not required.
• Side effects include bleeding and hypotension.
• Apixaban is contraindicated in clients weighing less than 50 kg due to increased bleeding risk.
• Interacts with other drugs and herbs that cause bleeding.

Anticoagulants: Heparin

• Heparin inhibits the action of thrombin, the conversion of fibrinogen to fibrin, and clot formation.
• Commonly used to prevent or treat venous thrombosis.
• Administered subcutaneously or intravenously
• Frequent lab monitoring is necessary.
• Heparin laboratory values: PTT 1.5 to 2.5 times normal (20-30 seconds), and aPTT 1.5 to 2.5 times normal (30-40 seconds), depends on facility
• Bleeding is a notable side effect, and injection site irritation is possible (do not massage).
• Protamine sulfate is the antidote.
• Contraindications include hemorrhagic stroke and bleeding issues.
• Use caution in clients with peptic ulcer disease.

Anticoagulants: Enoxaparin

• Enoxaparin is a low-molecular-weight heparin (LMWH) with a lower risk of bleeding.
• No frequent lab monitoring is required.
• Inactivates Xa factor.
• Used to prevent DVT and acute PE after orthopedic or abdominal surgery, typically starting 24 hours post-op.
• Aspirin concurrently or 4 G's should not be taken while using Enoxaparin.
• Administered once or twice daily via subcutaneous injection.

Thrombolytics: Alteplase

• Alteplase promotes the conversion of plasminogen to plasmin, degrading fibrinogen, fibrin, and other clotting factors to disintegrate clots.
• Dissolves clots following acute MI, pulmonary embolism, ischemic stroke, and DVT.
• All thrombolytics typically end in "-ase."
• Side effects include anaphylaxis and hemorrhage.
• Contraindications include bleeding, recent surgery or trauma, severe liver dysfunction, and head trauma.
• Interacts with other drugs and herbs that cause bleeding, including NSAIDs.

Nursing Process: Anticoagulants

• Assess baseline vital signs, CBC, PT, INR, PTT, and medical history.
• For thrombolytics, note recent surgeries or trauma and determine when the event started.
• Thrombolytics are most effective if given within 4 hours of MI onset or 3 hours of ischemic stroke.
• Report any history of blood thinners, including ibuprofen.
• Monitor vital signs, labs (CBC, PT/INR with warfarin, PTT with heparin, and All with alteplase).
• Monitor for bleeding and have antidotes for heparin and warfarin available.
• Watch for allergic reactions, and avoid venipuncture when possible.

Nursing Process: Teaching

• Inform to report signs and symptoms of bleeding and to use a soft toothbrush and electric razor.
• Ensure patient informs dentist of all medication use; advise on the importance of lab draws; wear a medic alert bracelet; stop smoking; avoid NSAIDs and other drugs that cause bleeding; exercise caution with herbal products; educate on how to stop bleeding.
• Maintain a consistent amount of vitamin for warfarin.