Hematologic: Heparin and Heparin Derivatives Flashcards
Types of anticoagulants
- heparin
- oral anticoagulants
- antiplatelet drugs
What are the brand and generic names of anticoagulants?
- Heparin
- Enoxaparin [Lovenox]
- Warfarin [Coumadin]
- Novel Anticoagulants (NOAC’s) (apixaban [Eliquis]
What type of drug is Enoxaparin [Lovenox]?
Heparin Derivative
How is Heparin prepared?
commercially from animal tissue
What is Heparins function?
prevent clot formation
What can Heparin NOT do?
can’t dissolve already formed clots
Why was Enoxaparin [Lovenox] created?
- prevent DVT (a blood clot in the deep veins-normally legs)
- in surgical patients
Why is Enoxaparin [Lovenox] preferred?
- SC
2. Less monitoring
How are Haparin and Heparin derivatives administered?
- Injection
2. IV
What type of injection is contraindicated for heparin and heparin derivatives? Why?
- IM
2. Risk of bleeding
Where are heparin and its derivatives metabolized?
Liver
How are heparin and its derivatives excreted?
Urine
Heparin and its derivatives: Steps- Actions
- Accelerates formation of an antithrombin III–thrombin complex
- Which inactivates thrombin
- And prevents the conversion of fibrinogen to fibrin
What is Heparin and its derivatives used to treat?
- DVT
- Pulmonary embolism
- Open-heart/ortho/intraabdominal surgeries
- Disseminated intravascular coagulation
- Unstable angina
- Post-MI
- Cerebral thrombosis in evolving stroke
- Left ventricular thrombi
- Heart failure
- History of embolism and atrial fibrillation
- Bypass/Hemodialysis/Blood transfusions
Adverse effects of Heparin and its derivatives?
- Hemorrhage
- Prolonged clotting time
- Thrombocytopenia
- Hypersensitivity reactions
What should you watch for in patients on Heparin and its derivatives?
- bleeding gums
- bruises
- petechiae
- epistaxis
- tarry stools
- hematuria, and hematemesis.
What can cause Heparin and its derivatives to be inefefctive?
Neutralized by protamine sulfate.
What labs to monitor for a patient on Heparin and its derivatives?
- HGB and HCT
- Platelet count
- PT
- INR
- PTT
Pharmacodynamics Specifics
Heparin and heparin derivatives prevent the formation of new thrombi. Here’s how heparin works:
- Heparin inhibits the formation of thrombin and fibrin by activating antithrombin III.
- Antithrombin III then inactivates factors IXa, Xa, XIa, and XIIa in the intrinsic and common pathways. The end result is the prevention of a stable fibrin clot.
- In low doses, heparin increases the activity of antithrombin IIIagainst factor Xa and thrombin and inhibits clot formation.
- Much larger doses are necessary to inhibit fibrin formation after a clot has been formed. This relationship between dose and effect is the rationale for using low-dose heparin to prevent clotting.
- Whole blood clotting time, thrombin time, and PTT are prolonged during heparin therapy. However, these times may be only slightly prolonged with low or ultra-low preventive dosages.
Why do we watch labs for platelets?
heparin-induced thrombocytopenia (HIT)
What do we do if HIT occurs?
Use thrombin inhibitors instead of heparin:
- Lepirudin
- Argatroban
- Bivalirudin
Drug-drug interactions with Heparin/heparin derivates
- Oral anticoagulants
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Iron dextran
- Clopidogrel
- Cilostazol
- Antiplatelet drug (aspirin, ticlopidine, or dipyridamole)
- Antihistamines
- Digoxin
- Penicillins
- Cephalosporins
- Nitroglycerin
- Nicotine
- Phenothiazines
- Tetracycline hydrochloride
- Quinidine
- Neomycin sulfate
- IV penicillin
- Protamine sulfate and administration of fresh frozen plasma
Heparin/heparin derivates AND oral anticoagulants REACTION RATIONALE
Because heparin and heparin derivatives act synergistically with all the oral anticoagulants, the risk of bleeding increases when the patient takes both drugs together. The prothrombin time (PT) and
international normalized ratio (INR), used to monitor the effects of oral anticoagulants, may also be prolonged.
Heparin/heparin derivates AND nonsteroidal anti-inflammatory drugs (NSAIDs), iron dextran, clopidogrel, cilostazol, antiplatelet drugs (aspirin, ticlopidine, dipyridamole) REACTION RATIONALE
The risk of bleeding increases
