Medications affecting the Hematologic system

Im not feeling very skibidi right now

What are the 2 stages that make up hemostasis following a blood vessel injury?

1. Formation of a platelet plug

2. Platelet plug is reinforced with fibrin

   • Fibrin is produced by 2 different pathways

Eventually, the clot is broken down by plasmin

Where are the 2 areas that thrombi can form, and what are their general characteristics?

Arterial

• Result of localized tissue injury and lack of perfusion

• Can form in legs due to peripheral artery disease

Venous

• Slow stagnant blood flow

• Thrombi forms with a long tail —> High change of embolism!

• Typically forms in lower extremities (DVT!)

What 3 main classes of drugs are utilized for the treatment of thromboembolic disorders?

What do they do?

1. Anticoagulants —> suppress fibrin production. Prevent clots.

2. Antiplatelets —> inhibit platelet aggregation. Prevent clots.

3. Thombolytics —> Actually breaks down a thrombi. Used in hospitals/critical care only.

What is the main action of anticoagulants, and what are they most effective against?

• Suppress the production of fibrin

• MOST effective against venous thrombus

(remember, venous thrombi form as a result of stagnation, which increases the effect of fibrin. Anti-fibrin —> reduces chance of venous thrombi forming)

What is the main action of antiplatelets, and what are they most effective against?

• Inhibit platelet aggregation

• MOST effective against arterial thrombus

(remember, arterial clots form as a result of localized injury, which platelets address. Anti-platelet —> Less chance of arterial clot forming)

What is a major concern with medications that alter the clotting system? How can we address this in patients?

• RISK FOR BLEEDING

  • Limit injections

  • avoid alcohol

  • Use soft bristle toothbrush and an electric razor

What category of drug are Cyclooxygenase Inhibitors?

What medication is most commonly associated with this?

Antiplatelet

Aspirin, NSAIDs

What is the pharmacological action of Aspirin?

• Inhibits cyclooxygenase, which is required for platelet synthesis

• Single dose lasts for 7-10 days (lifespan of platelets)

• Also inhibits prostaglandins

Results in:

• Analgesia

• Reduction of fever and inflammation

• Reduced platelets

What are the indications for the use of Aspirin / Cyclooxygenase inhibitors?

• Analgesia

• reduction of inflammation and fever

• Decreased incidence of Transient ischemic attack (mini strokes) and Myocardial infarction

How long does a single dose of aspirin last? Why is this important?

7-10 days. Lasts the entirety of the lifespan of a platelet. Overall reduction.

When is aspirin contraindicated for use?

• Use with other NSAIDs

• Bleeding disorders

• Thrombocytopenia

• 30 weeks pregnancy

• Children and adolescents

• GI bleed/ulcer

What is the value for thrombocytopenia? When are we technically allowed to still give aspirin?

•Thrombocytopenia < 150,000, but can give if over 100,000

What are the adverse reactions of Aspirin/Cyclooxygenase inhibitors?

• GI bleeding (prostaglandins can’t protect the GI mucosa)

• Dyspepsia (indigestion)

• Nausea

• Epigastric distress

• Hepatotoxicity

• Hypersensitivity

What category of drug are Glycoprotein inhibitors?

What is the prototype medication from this class?

Antiplatelet

Eptifibatide

What is the pharmacological action of Eptifibatide?

Bind to platelets, which prevents the binding of fibrin.

What are the indications for the use of Eptifibatide?

• Acute coronary syndrome

• Patients undergoing thrombolytic therapy

What category of drugs are ADP Inhibitor?

What is the prototype medication from this class?

Antiplatelet

Clopidogrel

What is the pharmacological action of Clopidogrel?

Irreversibly inhibits binding of ATP to platelet receptors —> Inhibition of platelet aggregation

What category of drugs are Arterial Vasodilators?

What is the prototype medication from this class?

Antiplatelet

Cilostazol

What is the pharmacological action of Cilostazol?

Inhibits the enzyme cAMP PDE III. Leads to increased cAMP in platelets —> Inhibits platelet aggregation, Vasodilation

What are the indications for Cilostazol?

Peripheral artery disease. Intermittent claudication.

When is Cilostazol contraindicated?

Heart failure

What category of drugs are Vitamin K Inhibitors?

What is the exemplar drug from this class?

Anticoagulation

Warfarin

What is the pharmacologic action of Warfarin?

Interferes with hepatic synthesis of vitamin k dependent clotting factors

Why is warfarin considered a dangerous medication?

Narrow therapeutic index.

Can lead to excessive bleeding.

What are the indications for the use of Warfarin?

• Prophylaxis and treatment of venous thrombus

• Pulm embolism

• A-fib and embolism

• Myocardial infarction management

• Prosthetic valve replacement - Thrombus prophylaxis

Why is warfarin indicated for use in cases of atrial fibrillation?

Blood in atria becomes stagnant. Leads to formation of clots, which typically travel to the brain.

What are the adverse reactions of Warfarin?

• BLEEDING

• Calciphylaxis (calcium build up)

• Dermal necrosis

• Hepatitis

True or false:

People that are taking warfarin should not eat any foods high in vitamin k.

FALSE.

They’re allowed. However, they shouldn’t go crazy with it. “Exercise caution”

What are the nursing considerations for the use of Warfarin?

• HIGH ALERT. Assess bleeding and hemorrhage

• Older adults are at risk for bleeding complications

  • Patients over 60 have higher PT/INR response

• THERAPEUTIC RANGE OF INR = 2-3

When assessing a patient who is taking warfarin for a-fib, you find that their INR of 3.5.

What is the appropriate action?

INR is supratherapeutic.

Omit warfarin dose,

Administer vitamin K if indicated.

When assessing a patient who is taking warfarin for a-fib, you find that their INR of 1.2.

What is the appropriate action?

INR is subtherapeutic.

Provider will likely increase dosing.

May order heparin temporarily.

Patient is at risk for stroke.

What category of medication is Heparin?

What are the 2 types of heparin?

ANTICOAGULANT

Unfractionated and low molecular weight

What is the pharmacological action of heparin?

Makes the effects of antithrombin more effective on factor X, thrombin (unfractionated), and prothrombin (LMW).

When is Unfractionated heparin contraindicated?

• History of heparin-induced thrombocytopenia

• Open wounds

• Severe liver/kidney impairment, active bleeding, ulcers

• Secere throbocytopenia (<100,000)

Adverse reactions of Unfractionated Heparin?

• Bleeding

• Alopecia

• Hyperkalemia

• Increased liver function test values

Nursing considerations for Heparin?

• Monitor aPTT, H&H, CBC

• Monitor aPTT every 4 hours in continuous IV therapy

• Assess potassium and LFTs

• WITH OVERDOSE: give Protamine Sulfate.

• HIGH ALERT MEDICATION

What are the normal values for hemoglobin?

13.5–17.5 for men.

12.5-15.5 for women.

In the case of an overdose on heparin, what should we give?

Protamine sulfate

What is a major difference in the pharmacologic action of Low Molecular Weight heparin vs Unfractionated?

LMW has smaller molecular chains.

More predictable, easier to administer and monitor.

LMW = Enoxaparin

What are specific nursing considerations for Enoxaparin?

• Can’t be used interchangeably with unfractionated

• DON’T EXPEL AIR BUBBLE from pre-filled syringe

• Inject ONLY in abdomen

What category of medication are Activated Factor XA Inhibitors?

What drug is commonly associated?

Anticoagulant.

Fondaparinux

What is the pharmacologic action of Fondaparinux?

Binds to antithrombin III —> Prevents activation of factor Xa —> Interrupts coagulation cascade —> Prevents thrombus

What is the indication for use of Fondiparinux?

Prevention and treatment of DVT and pulmonary embolism

Fondaparinux should be discontinued under what circumstances?

• “Unexpected changes” (?)

• Platelet count is <100,000

What is the only category of medication that directly breaks down a blood clot?

What is the name of the main medication associated with this class?

Thrombolytics

Alteplase

What is the pharmacological action of Alteplase?

Dissolves already formed clots.

Identical to tPA, which forms plasmin, digests the clotting factors.

What are the indications for the use of Alteplase?

When timely interventions are needed!

• Acute myocardial infarct

• Acute ischemic stroke

• Acute massive pulmonary embolism

• Blocked central venous device

What medication is used to reverse the effects of Alteplase?

IV aminocaproic acid

Nursing considerations for Alteplase?

• Serious risk for bleeding

• Reverse using IV aminocaproid acid

• Administer cimetidine or omeprazole to prevent GI bleed