COAGULATION MODIFIER DRUGSLilley Reading and Workbook, Chap 27

COAGULATION MODIFIER DRUGS Anticoagulants

Inhibit the action or formation of clotting factors Prevent clot formation

Antiplatelet drugs Inhibit platelet aggregation Prevent platelet plugs

Thrombolytic drugs Lyse (break down) existing clots

Hemostatic or Antifibrinolytic drugs Promote blood coagulation

HEMOSTASIS

The process that halts bleeding after injury to a blood vessel

Complex relationship between substances that promote clot formation and either inhibit coagulation or dissolve a formed clot

ANTICOAGULANTS

Have no direct effect on a blood clot that is already formed

Used prophylactically to prevent Clot formation (thrombus) An embolus (dislodged clot)

COAGULATION SYSTEM

“Cascade”

Each activated factor serves as a catalyst that amplifies the next reaction

Result is fibrin, a clot-forming substance

Intrinsic pathway and extrinsic pathway

ANTICOAGULANTS:MECHANISM OF ACTION

Vary, depending on drug Work on different points of the clotting cascade Do not lyse existing clots Heparin & low-molecular-weight heparins enoxaparin

(Lovenox) Turn off coagulation pathway and prevent clot formation

Warfarin (Coumadin)

All ultimately prevent clot formation

ANTICOAGULANTS

Prevention of clot formation also prevents:

Stroke Myocardial infarction (MI) Deep vein thrombosis (DVT) Pulmonary embolism (PE)

ANTICOAGULANTS: INDICATIONS

Used to prevent clot formation in certain settings where clot formation is likely

Stroke Atrial fibrillation

Myocardial infarction (MI) / Unstable Angina Deep vein thrombosis (DVT) Pulmonary embolism (PE) Indwelling devices, such as mechanical heart valves Major orthopedic surgery

ANTICOAGULANTS:ADVERSE EFFECTS

Bleeding Risk increases with increased dosages May be localized or systemic

May also cause Nausea, vomiting, abdominal cramps,

thrombocytopenia, others

ANTICOAGULANTS

Heparin

Monitored by activated partial thromboplastin times (aPTTs) Goal: Therapeutic range based on body weight

based dosage aPTT between 1.5 – 2.5 times normal control level

Parenteral – IV bolus followed by infusion Never mixed with any other medication Short half-life (1 to 2 hours) Effects reversed by protamine sulfate Obtained from sheep, cows, and pigs

HEPARIN: NURSING IMPLICATIONS

Anticoagulant effects seen immediately

Laboratory values are done daily to monitor coagulation effects (aPTT)

Intravenous doses are usually double checked with another nurse

Ensure that SC doses are given SC, not IM

SC doses should be given in areas of deep subcutaneous fat, and sites rotated

Bleeding precautions

ANTICOAGULANTS

Low-molecular-weight heparins

enoxaparin (Lovenox) dalteparin (Fragmin)

More predictable anticoagulant response Do not require frequent laboratory monitoring Given subcutaneously – rotate sites Patient may be instructed for home administration Bleeding precautions Protamine sulfate can be given as an antidote in case

of excessive anticoagulation

ANTICOAGULANTS

warfarin sodium (Coumadin)

Given orally only – usually late afternoon – same time daily

Monitored by INR (INR) - 2-4 depending on diagnosis (Prothrombin time – lab-specific -- 1 ½ - 2 ½ times the control 12-15

sec) Dose changed according to INR results

phytonadione (Vitamin K) can be given if toxicity occurs

WARFARIN - NURSING IMPLICATIONS

Assess: Patient history, medication history, allergies Contraindications Baseline vital signs, laboratory values Potential drug interactions—there are MANY! History of abnormal bleeding conditions Usually started 2-3 days prior to heparin infusion

being discontinued - until PT-INR levels indicate adequate anticoagulation Full therapeutic effect takes several days

Monitor PT-INR regularly—keep follow-up appointments

Antidote is phytonadione (Vitamin K)

WARFARIN -- NURSING IMPLICATIONS

Many herbal products have potential interactions—increased bleeding may occur

Capsicum pepper Garlic Ginger Gingko Ginseng Feverfew

ANTIPLATELET DRUGS

Indications

Antithrombotic effects Reduce risk of fatal and nonfatal strokes

Adverse effects Vary according to drug

ANTIPLATELET DRUGS

Prevent platelet adhesion Aspirin

dipyridamole (Persantine)

clopidogrel (Plavix) and ticlopidine (Ticlid) ADP inhibitors

tirofiban (Aggrastat), eptifibatide (Integrilin) New class, GP IIb/IIIa inhibitors

ANTIPLATELET DRUGS:NURSING IMPLICATIONS

Concerns and teaching tips

Same as for Anticoagulants

Dipyridamole should be taken on an empty stomach Drug-drug interactions Adverse reactions to report Monitoring for abnormal bleeding

ANTIFIBRINOLYTIC DRUGS

Prevent the lysis of fibrin Results: promote clot formation Used for prevention and treatment of

excessive bleeding resulting from hyperfibrinolysis or surgical complications

aminocaproic acid (Amicar) desmopressin (DDAVP)

Similar to ADH Also used in the treatment of diabetes

insipidus

ANTIFIBRINOLYTIC DRUGS:INDICATIONS

Prevention and treatment of excessive bleeding

Hyperfibrinolysis Surgical complications Excessive oozing from surgical sites such as

chest tubes Reducing total blood loss and duration of

bleeding in the postoperative period

ANTIFIBRINOLYTIC DRUGS:ADVERSE EFFECTS

Uncommon and mild

Rare reports of thrombotic events

Others include: Dysrhythmia, orthostatic hypotension, bradycardia,

headache, dizziness, fatigue, nausea, vomiting, abdominal cramps, diarrhea, others

THROMBOLYTIC DRUGS Drugs that break down, or lyse, preformed

clots

Older drugs streptokinase and urokinase

Newer drugs Tissue plasminogen activator (TPA) Anisoylated plasminogen-streptokinase

activator complex (APSAC)

THROMBOLYTIC DRUGS (CONT’D)

streptokinase (Streptase) anistreplase (Eminase) alteplase (t-PA, Activase) reteplase (Retavase) tenecteplase (TNKase) drotrecogin alfa (Xigris)

THROMBOLYTIC DRUGS: MECHANISM OF ACTION

Activate the fibrinolytic system to break down the clot in the blood vessel quickly

Activate plasminogen and convert it to plasmin, which can digest fibrin

Reestablish blood flow to the heart muscle via coronary arteries, preventing tissue destruction

THROMBOLYTIC DRUGS: INDICATIONS

Acute MI Arterial thrombolysis DVT Occlusion of shunts or catheters Pulmonary embolus Acute ischemic stroke – Code Green

THROMBOLYTIC DRUGS: ADVERSE EFFECTS

BLEEDING Internal Intracranial Superficial

Other effects Nausea, vomiting, hypotension, anaphylactoid

reactions Cardiac dysrhythmias

NURSING IMPLICATIONS

Assess:

Patient history, medication history, allergies Contraindications Baseline vital signs, laboratory values Potential drug interactions—there are MANY! History of abnormal bleeding conditions

THROMBOLYTIC DRUGS:NURSING IMPLICATIONS

Follow strict manufacturer’s guidelines for preparation and administration

Monitor IV sites for bleeding, redness, pain

Monitor for bleeding from gums, mucous membranes, nose, injection sites

Observe for signs of internal bleeding (decreased BP, restlessness, increased pulse)

ANTICOAGULANTS:PATIENT EDUCATION

Education should include:

Importance of regular lab testing Signs of abnormal bleeding Measures to prevent bruising, bleeding, or

tissue injury Wearing a medical alert bracelet Avoiding foods high in vitamin K (tomatoes,

dark leafy green vegetables) Consulting physician before taking other meds

or OTC products, including herbals

COAGULATION MODIFIER DRUGSNURSING IMPLICATIONS

Monitor for therapeutic effects

Monitor for signs of excessive bleeding Bleeding of gums while brushing teeth,

unexplained nosebleeds, heavier menstrual bleeding, bloody or tarry stools, bloody urine or sputum, abdominal pain, vomiting blood

Monitor for adverse effects Increased BP, headache, hematoma formation,

hemorrhage, shortness of breath, chills, fever

REVIEW

Antiplatelet agents act by:

1. preventing extension of existing clots.2. preventing platelets from uniting.3. dissolving existing clots.4. increasing blood viscosity.

REVIEW

Doses of heparin are based on what laboratoryreport?

1. warfarin serum level2. activated partial thromboplastin time(APTT)3. Lee White clotting time4. prothrombin time (PT) and INR

REVIEW

Nursing responsibilities involved in theadministration of heparin subcutaneouslyinclude:

1. checking calculations with a secondqualified nurse.2. using a 20-gauge needle to inject thedrug.3. injecting the drug deep intramuscularly(IM).4. aspirating before injecting the drug.

REVIEW

Clopidogrel (Plavix) is used to:

1. dissolve existing arterial blood clots.2. prevent further movement of an embolus.3. prevent platelet aggregation.4. prevent extension of an existingthrombus.