ANTIPLATELETS, ANTICOAGULANTM ANDTHROMBOLYTIC DRUGS Hina KarimNES Instructor

Coagulation Physiology

GLOSSARY Antithrombin III A protein found in our bloodstream that controls our clotting mechanism and prevents excessive clotting. It functions as a naturally occurring mild blood thinner.

Blood Clot Blood that has been converted from a liquid to a solid state. Also called a thrombus.

Coagulation complex process by which clots form in the blood.

Fibrin is a solid substance (formed from fibrinogen) that makes a clot harder to break up. It forms the mesh or net that holds platelets in place.

Fibrinogen A specialized protein or clotting factor found in blood. When a blood vessel is injured, thrombin, another clotting factor, is activated and changes fibrinogen to fibrin.

INR (International Normalized Ratio) blood test that monitors whether the therapeutic or beneficial effect of anticoagulation is within normal range, usually between 2.0 and 3.0. It is calculated from the prothrombin time (PT), or the time it takes for blood to clot in a test tube.

Platelets Small particles in the blood that control bleeding; they form clusters to plug small holes in blood vessels and assist in the clotting process.

Thrombocytopenia A low platelet count.

Vitamin K A vitamin essential to the production of the active forms of clotting factors II, VII, IX and X in the liver.

ANTI PLATELETS DRUGS

MECHANISM OF ACTION

An antiplatelet drug is a member of a class of drugs that decreases platelet aggregation and inhibits thrombus formation.

Anti platelets drugs inhibits:Inhibits cyclo-oxygenase and blocks the production of thromboxane. (asprin)inhibit the binding of adenosine diphosphate to its platelet receptor and inhibit platelet aggregation by blocking activation of the glycoprotein IIb/IIIa pathway. (Clopidogrel)Glycoprotein IIb/IIIa inhibitors (abciximab, eptifibatide, and tirofiban) block the binding of fibrinogen to glycoprotein IIb/IIIa receptors on the platelet

INDICATIONS Prophylaxis of venous thrombosis.Transient cerebral ischemic attacks.Following coronary artery bypass grafting.Prevention of myocardial infarction.Following coronary artery angioplasty.Prosthetic heart valves.

DRUGS Aspirin Aspirin plus clopidogrel (Plavix)Clopidogrel (Plavix)AggrastatPersantine

NURSING CAREWatch for side effects: GI upset, nausea, vomiting, stomach pain and loss of appetite. It is important to identify the presence of these side effects since it might interfere with patient compliance.

also watch for dizziness, weakness,severe headache,blood in urine or stool,nosebleeds, any unusual bleeding or bruising

Avoid if possible IM or SQ injections. If unavoidable, apply pressure to site for 5 minutes

Monitor platelet count periodically

ANTICOAGULANT DRUGS

ANTICOAGULANT DRUGSblood thinnersIt lengthen the time takes for blood to clot, rather than actually thinning the blood.They inhibit clot formation by blocking the action of clotting factors or platelets.They are used to prevent blood clotsinjected either into a vein or under the skin

MECHANISM OF ACTIONActivation of anticlotting factors (especially antithrom bin III) e.g. HEPARINDirect inhibition of thrombin e.g. HIRUDIN inhibition of synthesis of blood coagulation factor precursors (zymogens) e.g. WARFARINActivated Protein C i.e., DROTRECOGIN ALFA

HEPRIN antidote = Protamine Sulphate

Warfarin antidote = Vitamin K

NURSING CARE watch patient for bleeding: epistaxis, gum bleeding, hemoptysis, hematuria, melena or hemorrhage.Heparin-induced thrombocytopeniaLaboratory monitoring typically includes measurements of coagulations, such as activated partial thromboplastin time (aPTT), prothrombin time (PT), plasma heparin concentration (antifactor UFH Xa), whole blood clotting time, activated clotting time, plus a complete blood count (CBC) to monitor platelets and assess for bleeding.

patients who will self-administer LMWH must be instructed on correct subcutaneous administration technique.Foods containing vitamin K may decrease anticoagulation and INR.Monitor vital signs. (Increase in heart rate accompanied by low blood pressure or subnormal temperature may signal bleeding.)

THROMBOLYTIC DRUGS

MECHANISM OF ACTIONThrombolysis is the breakdown (lysis) of blood clots by pharmacological means.It works by stimulating fibrinolysis by plasmin through infusion of analogs of tissue plasminogen activator, the protein that normally activates plasmin.

DRUGS Streptokinase :Indications ST elevation myocardial infarction. Arterial thrombosis. Deep vein thrombosis. Pulmonary embolism. Intra-arterial or intravenous catheter occlusion.

t-PAIndications ST elevation myocardial infarction. Arterial thrombosis. Deep vein thrombosis. Pulmonary embolism. Intra-arterial or intravenous catheter occlusion.

ADVERSE EFFECTS Major bleeding.Cardiac arrhythmias.Cholesterol embolus syndrome.Anaphylactic reaction.Cerebrovascular accident.Intracranial hemorrhage.

STEPTOKINASE ADVERSE EFFECTSNon-cardiogenic pulmonary edema.Hypotension.Fever and shivering.History of cerebrovascular hemorrhage at any time.Non-hemorrhagic stroke or other cerebrovascular event within the past year.Marked hypertension ( reliably determined systolic arterial pressure >180 mmHg and/or a diastolic pressure >110 mmHg) at any time during presentation.

Streptokinase Contraindication

trauma or surgery within 10 days, active internal bleeding

recent (within 2 months) stroke, intracranial or intraspinal surgery

recent head trauma or known intracranial neoplasm

blood pressure > 200/ 120 mmHg (after pain relief)

pregnancy

use of Streptase is contraindicated in patients with streptococcal infections

Dosage:

Acute Myocardial Infarct:- 1 500 000 IU with or without aspirin over 1 hour. Administration should be commenced within 4-6 hours after the onset of pain and within 1 hour of hospital presentation.

Route: IV

Dilution:

1 500 000 IU to be diluted in 100 mls of normal saline or 5% dextrose

infuse at a rate of 8 ml/hr

NURSING CARE

Acute myocardial infarction:-

give ASAP after onset of symptoms.

insert 2 peripheral 16g cannulae

give aspirin 150 mg prior to streptokinase

record ECG pre and post streptakinase

1 500 000 IU diluted in 100 mls of normal saline or 5% dextrose and given over 30-60 mins depending on the patients reaction.

Continuous monitoring of ECG, and BP

Observe for reperfusion arrhythmias and bleeding