Hemostasis

physiological process of stopping bleeding

stages of hemostasis

stage 1 - formation of platelet plug

stage 2 - reinforcement of platelet plug by fibrin (coagulation)

Thrombosis

blood clot formed within a blood vessel or the heart

heparin

quickly suppresses coagulation by helping antithrombin inactivate thrombin & factor Xa

Use: PE; evolving stroke; massive DVT; open heart surgery; renal dialysis; DIC(deseminated intravascular coagulation[causes clotting throughout body]); prophylaxis for venous thrombosis; pregnancy(does not cross the placenta)

Effects: anyticoagulant by suppression of fibrin formation (stage II hemostasis)

AE: hemorrhage, spinal epidural hematoma, HIT(Heparin Induced Thrombocytopenia)

DD: ASA, ibuprofen (depress platelet formation - only defense against hemorrhage during heparin use)

antidote: protamine sulfate (neutralizes heparin)

lab monitoring (heparin)

aPTT - activated partial thromboplastin time (specific to heparin)

measures the clotting time (normal 40 seconds)

therapeutic range: 60-80 seconds

enoxaparin (Lovenox)

heparin derivative

preferential inactivation of factor Xa

Use: prevention of DVT > abd surg., hip/knee replacement; Tx established DVT's w/ or w/o PE; ischemic complications from unstable angina & MI

AE: bleeding, severe neurological injuries, including permanant paralysis, during LP or spinal/epidural anesthesia, thrombocytopenia

Advantage: can be given @ home; less blood monitoring; less likelihood of thrombocytopenia

antidote: protamine sulfate

NO ROUNTINE LABS

warfarin (Coumadin)

oral anticoagulant

coagulation suppression by antogonist of Vitamin K

does not dissolve clot

Use: long-term prophylaxis of thrombosis (venous; PE; prosthetic heart valves; a. fib.); ↓ risk of recurrent TIA's & MI

Effects: ↓ in thrombosis formation

AE: hemorrhage; fetal hemorrhage; teratogenic category X

DD: drugs that interfere w/ coagulation (↑ risk of hemorrhage), ASA, Heparin, acetaminophen, cimetidine (Tagamet)(↑ anticoagulant effects), phenytoin, oral contraceptives (↓ anticoagulant effects)

antidote: vitamin K

lab monitoring: PT(prothrombin time) - measures clotting time (normal ~ 12 seconds); INR(international normalized ratio) 2-3

fondaparinux (Arixtra)

produce selective inhibition of factor Xa whereas heparin's inactivate both thrombin & factor Xa

Use: DVT prevention after hip Fx surgery, hip/knee replacement, Tx acute PE and acute DVT

AE: ↑ risk of bleeding w/ older adult and renal impairment, no risk of HIT, can ↓ platelet count

bivalirudin (Angiomax)

non heparin agent

direct thrombin inhibitors

anticoagulant given w/ ASA during angioplasty & coronary intervention (stent)

synthetic drug related to saliva of leeches

dabigatran (Pradaxa)

direct thrombin inhibitor, preventing thrombus formation

oral anticoagulant- new (october 2010)

Use: A-fib (non-valvular), prevent stroke & systemic embolism/ for use adults only

AE: ↑ risk for bleeding (GI, intercranial), GI: dyspepsia, gastritis, esophagitis - ↓ by taking w/ food

DD: drugs that interfere w/ coagulation ↑ risk of hemorrhage, NSAIDs, Plavix, giving w/ other anticoagulants - warfarin, heparin, Lovenox; ↑ effect amiodarone, ketoconazole, verapamil, quinidine

NO ROUTINE LAB TEST, MONITOR FOR S/S BLEEDING

no antidote

rivaroxaban (Xarelto)

selective inhibitor factor Xa, inhibits thrombin

new 11/2011

Use: A-Fib (non-valvular) prevent stroke, prophylaxis DVT/PE post op hip or knee replacement surgery

AE: ↑ risk for bleeding, spinal/epidural hematoma, hypersensitivity rxn (anaphylaxis)

DD: other anticoagulants, caution in use w/ antiplatelet & fibrinolytics

caution in pts w/ renal impairment delays excretion leading to ↑ risk of bleeding

teratogenic category C

NO ROUTINE LAB TEST, MONITOR FOR  S/S BLEEDING

aspirin (ASA)

antiplatelet

supress platelet aggregation by inhibition of cyclooxygenase (COX)

Use: acute MI, coronary stents, primary prophylaxis of MI, prevent reinfarction; prevention of stroke in pts w/ Hx of TIA's

Effects: ↓ risk of arterial thrombosis

AE: ↑ GI bleeding and stroke

clopidogrel (Plavix)

antiplatelet

↓ platelet aggregation

Use: prevention of stenosis coronary stents and thrombotic stroke(type of ischemic stroke); MI

Effects: prevention of thrombosis

AE: bleeding; thrombotic thrombocytopenia purpura (TTP), GI disturbances

DD: other drugs that promote bleeding; Prilosec; ↓ antiplatelet effects

abciximab (Reopro)

antiplatelet

glycoprotein receptor antagonists; the most effective antiplatelet drugs

Use: prevent ischemic events in pts w/ acute coronary syndrome - unstable angina & MI leading to thrombosis; angioplasty

Effects: prevent aggregation of platelets leading to thrombosis

AE: bleeding

cilostazol (Pletal)

antiplatelet

antiplatelet inhibition; vasodilation

Use: intermittent claudication(pain, cramping, weakness of the calf muscles)

Effects: pain relief

AE: HA; diarrhea

alteplase (Activase) (tPA - tissue plasminogen activator)

thrombolytic

enzymatic conversion of plasminogen to plasmin

Use: acute MI; acute massive PE; acute ischemic stroke

Effects: breakdown thrombosis

AE: bleeding, particularly intracranial bleeding; (no hypotension or allergic reaction)

breaks down clots

ferrous sulfate

drug for deficiency anemia - Fe(iron) Salts

↑ blood levels of iron

Use: iron deficiency anemia; prophylaxis of iron deficiency; pregnancy; chronic blood loss (women w/ heavy menstral periods that don't want a histerectomy)

Effects: elevate serum iron levels

AE: GI disturbance (N, heartburn, constipation, diarrhea); liquid iron (mainly used in children) can stain teeth

DD: antacids reduce absorption of Fe; vitamin C ↑ adverse effects although it promotes Fe absorption

Toxicity: death in young children  (lethal dose 2-10 g)

antidote: deferoxamine (Desferal)

iron dextran (INfed)

drugs for deficiency anemias - parenteral(if oral cannot be taken)

↑ serum Fe

Use: iron deficiency in pts who cannot tolerate or absorb PO Fe; severe blood loss

Effects: ↓ iron deficiency anemia

AE: anaphylaxis (potentially fatal)

avoid IM if possible - persistant pain, discoloration of site, tumors, greater risk of anaphylaxis (always do a test dose, IM or IV)

cyanocobalamin

vitamin B12 deficiency

↑ B12 levels

Use: megaloblastic anemia (oversized RBCs in blood stream, which are ineffective); B12 deficiency demyelination of neurons(desinegration of nerve coating)

Effects: reversal of anemia

AE: hypokalemia (due to ↑ in erythrocyte formation)

folic acid (Folate)

folic acid deficiency

essential factor in DNA synthesis

Use: megaloblastic anemia; folic acid deficiency r/t alcoholism; pregnancy & lactation; sprue (intestinal malabsorption)

Effects: ↑ folic acid levels

AE: nontoxic short term; long term in large doses ↑ risk of colorectal & prostate cancer

can mask vitamin B12 deficiency

epoetin alfa/Erythropoietin (Epogen)

hematopoietic growth factors - erythropoietic

(↑ production in RBCs)

Use: anemia of chronic renal failure; chemotherapy-induced anemia; zidovudine (AZT)-induced anemia (HIV drug caused)

Effects: ↑ serum RBC's

AE: HTN

filgrastim (Neupogen)

hematopoietic growth factors - leukopoietic

↑ production of WBCs

Use: cancer chemotherapy; bone marrow transplant; chronic neutropenia

Effects: ↑ serum neutrophils (aka granulocytes)

AE: bone pain; leukocytosis(to much WBC)

sargramostin (Leukine)

hematopoietic growth factors

stimulates bone marrow to ↑ neutrophils & macrophages

Use: bone marrow transplant in cancer pts; Tx of failed bone marrow transplants, pts w/ AML

Effects: ↑ neutrophils as well as macrophages

AE: D; bone pain; leukocytosis & thrombocytosis

oprelvekin aka interleukin II (Neumega)

thrombopoietic growth factors

↑ platelet production

Use: chemotherapy for Tx of thrombocytopenia

Effects: ↑ blood clotting

AE: fluid retention; cardiac dysrhythmias, severe allergic rxn