MEDSURG PPT

ANTI-COAG/ANTI-PLATELET DRUGS

What Are Anti-Coag/Anti-Platelet Drugs?

  • Definition: Anticoagulants and antiplatelet drugs are medications designed to reduce the risk of blood clot formation but they operate at different stages of the clotting process.

Overview of Anti-Coagulants and Anti-Platelet Drugs

  • Terminology: Commonly referred to as "blood thinners"; however, these medications do not actually thin the blood.

  • Functionality:

    • They work on the coagulation cascade, targeting various clotting factors.

    • They inhibit the formation and growth of fibrin clots.

  • Common Uses:

    • Anticoagulants are used for:

    • Deep vein thrombosis (DVT)

    • Pulmonary embolism (PE)

    • Atrial fibrillation (stroke prevention)

    • Antiplatelet drugs are used for:

    • Heart attack (myocardial infarction) prevention

    • Stroke prevention

    • Post-stent placement procedures

Anticoagulants

Mechanism of Action

  • Activation of Antithrombin III:

    • Inhibits:

    • Thrombin (Factor IIa)

    • Factor Xa

    • This action prevents the conversion of fibrinogen to fibrin, thus inhibiting clot formation.

Indications

  • Treatment and prevention of DVT/PE

  • Acute coronary syndromes (ACS)

  • During surgical procedures (e.g., cardiac surgery)

  • Dialysis anticoagulation

Heparin (Heparin Sodium)

  • Side Effects:

    • Bleeding

    • Heparin-induced thrombocytopenia (HIT)

    • Osteoporosis (long-term use)

    • Hyperkalemia (rare)

  • Nursing Considerations:

    • Monitor activated Partial Thromboplastin Time (aPTT) with a goal of ~1.5–2.5× normal levels.

    • Monitor platelet counts due to HIT risk.

    • Antidote: protamine sulfate.

    • Administration: IV or subcutaneous (never intramuscular).

  • Patient Education:

    • Report any instances of bleeding or bruising.

    • Avoid NSAIDs unless prescribed.

    • Use a soft toothbrush or electric razor to minimize bleeding risk.

Low Molecular Weight Heparin (LMWH) - Enoxaparin (Lovenox)

  • Mechanism of Action:

    • By inhibiting Factor Xa, LMWH reduces the conversion of prothrombin to thrombin, ultimately resulting in decreased fibrin clot formation.

  • Indications:

    • DVT/PE prevention and treatment

    • Post-surgical prophylaxis

    • Acute Coronary Syndrome (both NSTEMI and STEMI)

  • Side Effects:

    • Bleeding

    • Injection site bruising

    • Lower risk of HIT compared to unfractionated heparin (regular heparin).

  • Nursing Considerations:

    • No routine aPTT monitoring is necessary.

    • Monitor renal function since LMWH is renally excreted.

    • Antidote is protamine sulfate (partial effect).

    • Administer via subcutaneous injection (do not expel the air bubble).

  • Patient Education:

    • Teach the patient proper self-injection techniques.

    • Do not rub the injection site post-injection.

    • Report any unusual bleeding promptly.

Apixaban (Eliquis)

  • Mechanism of Action:

    • Direct Factor Xa inhibitor that selectively and reversibly blocks Factor Xa in the coagulation cascade, preventing the formation of fibrin clots.

  • Indications:

    • Atrial fibrillation (for stroke prevention)

    • Treatment and prevention of DVT/PE

    • Post-orthopedic surgery prophylaxis

  • Side Effects:

    • Bleeding

    • Anemia

    • Easy bruising

    • Nausea (less common)

  • Nursing Considerations:

    • No routine coagulation monitoring needed unless clinically indicated.

    • Monitor renal and liver function for safety.

    • Antidote: andexanet alfa.

  • Patient Education:

    • Consistency in intake is important; do not skip any doses.

    • Avoid over-the-counter NSAIDs unless cleared by a provider.

    • Routine blood tests are not necessary but make sure to attend follow-up appointments.

Rivaroxaban (Xarelto)

  • Mechanism of Action:

    • Direct Factor Xa inhibitor that selectively blocks Factor Xa in the coagulation cascade.

    • Functions independently of antithrombin III.

    • Reduces thrombin generation to prevent clot formation.

  • Indications:

    • Stroke prevention in non-valvular atrial fibrillation

    • DVT and PE treatment

    • Prevention of recurrent DVT/PE

    • Post-operative thromboprophylaxis

  • Side Effects:

    • Increased risk of gastrointestinal (GI) bleeding compared to some other direct oral anticoagulants (DOACs).

    • General bleeding risks.

  • Nursing Considerations:

    • Administration should be with food to enhance absorption.

    • Monitor renal function to ensure drug efficacy and safety.

    • Antidote: andexanet alfa for emergencies.

  • Patient Education:

    • Instruct patients to take the medication with meals.

    • Avoid abrupt cessation of the medication as this increases clotting risk.

    • Be vigilant for signs of bleeding or unusual bruising.

Anti-Platelet Drugs

Clopidogrel (Plavix)

  • Mechanism of Action:

    • P2Y12 (ADP) receptor inhibitor that irreversibly blocks ADP receptors on platelets.

    • This action prevents the activation of GPIIb/IIIa receptors, which are critical in platelet aggregation.

  • Indications:

    • Used in acute coronary syndrome (ACS)

    • Post-cardiac stent placement

    • Stroke and myocardial infarction prevention

  • Side Effects:

    • Bleeding

    • Gastrointestinal upset

    • Rash

    • Rarely: Thrombotic Thrombocytopenic Purpura (TTP)

  • Nursing Considerations:

    • No routine lab monitoring is mandated.

    • Check for potential drug interactions (notably, omeprazole can diminish its effectiveness).

    • Recovery of platelet function typically takes about 5–7 days after discontinuing.

  • Patient Education:

    • The patient should take the medication daily as prescribed.

    • Inform all healthcare providers before undergoing any surgical or dental procedures.

    • Report any unusual bleeding to the healthcare provider immediately.

Aspirin (Bayer, Ecotrin)

  • Mechanism of Action:

    • Irreversible COX-1 inhibitor that blocks the production of thromboxane A₂ (TXA₂) in platelets.

    • Results in decreased platelet activation and aggregation.

  • Indications:

    • Prevention of heart attack and stroke.

    • Given during suspected acute coronary syndrome (ACS).

    • Used post-stent placement (often in conjunction with clopidogrel as dual antiplatelet therapy, DAPT).

  • Side Effects:

    • Gastrointestinal irritation

    • Bleeding

    • Tinnitus

    • Reye's syndrome (a rare but serious condition)

    • Hypersensitivity reactions

  • Nursing Considerations:

    • Monitor for signs of gastrointestinal bleeding.

    • Use with caution in patients already on anticoagulants.

    • There is no specific antidote for aspirin; supportive care is needed for overdose.

  • Patient Education:

    • Take the medication with food to minimize GI upset.

    • Advise to avoid alcohol as it may increase the risk of GI bleeding.

    • Report any ringing in the ears or unusual bleeding.

References

  • Cleveland Clinic. "Aspirin Tablets." Cleveland Clinic, Cleveland Clinic, 2024, my.clevelandclinic.org/health/drugs/20592-aspirin-tablets.

  • ------. "Clopidogrel (Plavix): Uses & Side Effects." Cleveland Clinic, 2023, my.clevelandclinic.org/health/drugs/20743-clopidogrel-tablets.

  • ------. "Heparin: An Enemy of Blood Clots." Cleveland Clinic, 2 June 2023, my.clevelandclinic.org/health/treatments/16017-heparin-infusion.

  • Mayo Clinic. "Apixaban (Oral Route) Description and Brand Names - Mayo Clinic." Www.mayoclinic.org, 1 Feb. 2024, www.mayoclinic.org/drugs-supplements/apixaban-oral-route/description/drg-20060729.

  • "Rivaroxaban (Xarelto): Uses & Side Effects." Cleveland Clinic, my.clevelandclinic.org/health/drugs/19858-rivaroxaban-tablets.

  • Sinha, Sanjai. "Lovenox." Drugs.com, Drugs.com, 2019, www.drugs.com/lovenox.html.