Hematology/acne Flashcards
Virchow’s triad
Thrombophilic abnormalities, vascular endothelial injury, stasis
Warfarin: MOA
Inhibits synthesis of vitamin K dependent clotting factors (e.g. factor X, IX, VII, II)
Decline of clotting factors is function of long half lives (can be as long as 3-4 days until see Warfarin effects)
Heparin: MOA
Accelerates activity of antithrombin III –> inactivates thrombin and other anticoagulation factors (factor Xa)
Prevents conversion of fibrinogen to fibrin
Warfarin: indications
Thrombosis, embolism, afib, prosthetic heart valves
LMWH: MOA
Accelerates activity of antithrombin III and inactivates factors Xa and IIa (thrombin)
Heparin: indications
Prevention of postoperative thromboembolism
LMWH: indications
DVT and/or pulmonary embolism, prophylaxis
Dabigatran (Pradaxa): indications
Reducing risk of stroke and systemic embolism in patients with nonvalvular afib
Dabigatran (Pradaxa): MOA
Direct thrombin inhibitor
Thrombin required for the conversion of fibrinogen to fibrin in clotting cascade
Rivaroxaban, Apixaban, Edoxaban, Betrixaban: indications
Treatment of DVT and/or pulmonary embolism, reduction of stroke and systemic embolism in nonvalvular afib
Rivaroxaban, Apixaban, Edoxaban, Betrixaban: MOA
Direct factor Xa inhibitors
What are the steps to platelet adhesion?
1) Platelet receptor binds to von Willebrand factor, bridging platelet to injury site
2) Mediators are released - serotonin and histamine–> immediate vasoconstriction
3) Reduction in blood flow and bleeding
4) Vasodilation to permit inflammatory process to occur
Aspirin: indications
MI and stroke prevention, acute coronary syndrome
Aspirin: MOA
Irreversibly antagonizes COX pathway which interferes with platelet aggregation
Concurrent use with what medication is contraindicated with anticoagulant therapy?
NSAIDS (also act on the cyclooxyrgenase pathway like ASA)
Clopidrogel (Plavix): indications
Unstable angina, recent MI, acute coronary syndrome
Clopidrogel (Plavix): MOA
Reduces platelet aggregation by inhibiting the ADP pathway
Unlike ASA, has no effect on prostaglandins
What medication can be used as a substitute if ASA is contraindicated?
Clopidrogel (Plavix)
Heparin: absorption and distribution
Not absorbed by the GI tract –> must be given IV or SC
Distributed in plasma and highly protein bound
LMWH: absorption and distribution
Not absorbed by the GI tract –> must be given IV or SC
Distributed in plasma and have limited or no protein binding
Warfarin: absorption and distribution
Rapidly and completely absorbed orally
Serum levels found in 1-2 hours but anticoagulant effects dependent on depletion of clotting factors (factor II has a half-life of 72 hours) –> full effect does not occur for 3-4 days
Highly bound to plasma protein
Aspirin: absorption and distribution
Rapidly and completely absorbed after oral administration
Protein binding highest with low plasma concentrations and lower with high concentrations
Heparin: contraindications
Advanced hepatic/renal impairment, pregnancy
Heparin: cautions
When combining with conditions that may predispose to hyperkalemia or drug regimens
Compatible with lactation