Anticoagulants - Heparin: Nursing pharmacology

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Unfractionated heparin;
Low molecular weight heparin (LMWH): enoxaparin (Lovenox), dalteparin (Fragmin), tinzaparin (Innohep)
Enhance the activity of antithrombin III → inhibit Factor Xa and Factor IIa (thrombin) → stop coagulation cascade
  • Deep vein thrombosis, pulmonary embolism
  • Ischemic stroke, transient ischemic attack
  • Coronary artery disease
  • Cardiac valve replacement or coronary angioplasty
  • Coagulation disorders like antiphospholipid syndrome and DIC
  • Dialysis
  • Surgical procedures: cardiopulmonary bypass, ECMO, PCI
  • Unfractionated heparin: IV, SubQ
  • LMWH: SubQ
  • Undue bleeding (antidote: protamine sulfate for unfractionated heparin; partially effective for LMWH)
  • Injection site reactions
  • Hyperkalemia
  • Heparin-induced thrombocytopenia (HIT)
  • Osteoporosis
  • Active internal bleeding
  • Trauma in the past three months
  • History of intracranial hemorrhage or ischemic stroke
  • Gastrointestinal ulcers
  • Coagulopathies, bleeding disorders
  • Thrombocytopenia
  • History of HIT
  • Antiplatelet and thrombolytic medications (increased risk of bleeding)
  • Allergies to porcine products
  • Hepatic or renal disease
  • Alcohol use disorder
Unfractionated heparin, LMWH
Focused baseline assessment
  • Weight
  • Vital signs
  • Laboratory test results; CBC, PTT, aPTT, renal function tests

  • Confirm prescribed dose per kg
  • Double check prescribed dose with a second nurse
  • Have protamine sulfate readily available
  • Unfractionated heparin SubQ
    • Inject 2 inches or 5 centimeters away from client’s navel
    • Pinch the skin slightly
    • Insert the needle at a 90 degree angle
    • Inject slowly
    • Withdraw needle; lightly press the site with dry gauze or an alcohol swab - do not massage the injection site
  • Unfractionated heparin IV
    • Ensure patent IV catheter
    • Follow facility protocol
      • Calculate units of heparin / kg / hr
      • Adjust infusion per PTT
  • Monitor for signs / symptoms of bleeding; clot formation; aPTT; platelets
Purpose of medication
  • Prevent clot formation

  • Signs of bleeding; e.g., oozing from the IV insertion site, nosebleed, sudden headache
  • Signs of clot formation; e.g., new pain, swelling, or warmth in their leg; shortness of breath; sudden onset of confusion, vision changes, trouble speaking, or one-sided weakness

LMWH (e.g., enoxaparin) self-administration
  • Review appropriate technique for subcutaneous injections using prefilled syringe
  • Inject the medication once per day, at the same time each day
  • May feel minor discomfort or slight bruising may occur at the injection site
  • Teach bleeding precaution; e.g., soft bristled toothbrush, electric razor; avoiding medications that affect platelets, avoiding activities that can cause injuries
  • Contact healthcare provider for signs of minor bleeding; e.g., bleeding gums, nosebleeds, longer than normal menstrual periods
  • Seek emergency medical care immediately
    • Falls or injuries
    • Signs of significant bleeding such as dark urine or stools, coughing up blood, heavy bleeding from a minor cut, or sudden back pain
    • Signs of clot formation; new leg pain, swelling, or warmth; shortness of breath; sudden onset of confusion; vision changes; trouble speaking; or one-sided weakness


Anticoagulants are medications that work by interfering with the functional clotting factors in the coagulation cascade, and are used to prevent the formation of thrombi, or blood clots, and are used to prevent or treat thromboembolic events, such as deep vein thrombosis, pulmonary embolism, ischemic stroke, transient ischemic attack, coronary artery disease or myocardial infarction.

They're also used in clients with coagulation disorders, including antiphospholipid syndrome and disseminated intravascular coagulation; as well as in clients who underwent cardiac valve replacement or coronary angioplasty; and during surgical procedures like cardiopulmonary bypass, percutaneous coronary intervention, extracorporeal membrane oxygenation, and in clients undergoing dialysis.

Among the most important anticoagulants are heparins. These include unfractionated heparin, which is derived from porcine sources, and can be administered intravenously or subcutaneously; as well as low molecular weight heparins or LMWHs, which are synthetic analogs of certain portions of the heparin molecule. These include enoxaparin, dalteparin, and tinzaparin, and are given subcutaneously.

Once administered, heparins work by binding to and enhancing the activity of antithrombin III, which is an anticoagulant protein synthesized by the liver.


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