Class
- Anticoagulant
Heparin
Commonly Prescribed for
(FDA approved in bold)
- Deep venous thrombosis (DVT)/pulmonary embolism (PE)
- Atrial fibrillation with embolization
- Prevention of evolving thrombosis in acute ischemic stroke (IS)
- Coagulopathies (acute and chronic)
- Prophylaxis against postoperative DVT/PE in at-risk patients
- Clotting prevention (i.e., during procedures)
- Prophylaxis of left ventricular thrombi and cerebrovascular accidents post-myocardial infarction (MI)
- Unstable angina
- After thrombolysis in acute MI
Heparin
How the Drug Works
- Inhibits multiple sites in the coagulation system, preventing normal clotting of blood and formation of fibrin clots. Heparin, in combination with antithrombin III, inactivates activated Factor X and prevents the conversion of prothrombin to thrombin
- Larger doses inhibit further coagulation by inactivating thrombin and preventing conversion of fibrinogen to fibrin and inhibiting the activation of fibrin stabilizing factor
Heparin
How Long Until It Works
- IV bolus: anticoagulant effect is immediate but increases in proportion to dose and duration of use. SC: peak levels occur at 2–4 hours
Heparin
If It Works
- Monitor for bleeding complications and check activated partial thromboplastin time (aPTT)
Heparin
If It Doesn’t Work
- Patients can still have DVT/PE or IS despite treatment. Check aPTT to determine effectiveness
Heparin
Best Augmenting Combos for Partial Response or Treatment-Resistance
- Often used with aspirin adjunctively in the setting of acute MI and coronary occlusion
- Usually used in acute setting after cardioembolic IS. Warfarin is usually used for long-term prophylaxis
Heparin
Tests
- Monitor prothrombin time (aPPT) and INR to determine effectiveness. Periodically monitor platelet counts and test for occult blood in stool
Adverse Effects (AEs)
Heparin
How Drug Causes AEs
- Anticoagulation increases bleeding risk, hypersensitivity accounts for most other AEs
Heparin
Notable AEs
- Generalized hypersensitivity (chills, fever, urticaria, rhinitis, headache). Mild thrombocytopenia. Osteoporosis with extended use
Heparin
Life-Threatening or Dangerous AEs
- Heparin can cause retroperitoneal, adrenal, ovarian, GI, urinary tract, or intracranial bleeding. Complications can be life-threatening. Patients at increased risk include those with liver or renal disease, severe hypertension, bacterial endocarditis, ulcerative colitis, and diverticulitis
- Delayed thrombocytopenia (usually starting 7–12 days after initiation) can be severe. This can lead to new thrombus formation from irreversible platelet aggregation, called “white-clot syndrome.”
- Vasospasm in limbs, up to 6 hours, may occur 6–10 days after initiating therapy
- Hypersensitivity reactions, including asthma, shock, or anaphylaxis
Heparin
Weight Gain
- Unusual
Heparin
Sedation
- Unusual
Heparin
What to Do About AEs
- Stop infusion for serious AEs. Thrombocytopenia is not necessarily dose-related. Stop if platelets are below 100,000/mm3 or if recurrent thrombosis develops. Consider alternative anticoagulants, if patients require them
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
