Anticoagulant Drugs

Question 1

The clotting process involves which three events? Give a brief explanation of what occurs in each event.

Answer 1

1. Vasoconstriction is the first reaction to an injury.
2. Platelet aggregation (platelet plug)
   - platelets become sticky and release ADP and serotonin to have a platelet party.
3. Cascade of clotting factors can be extrinsic or intrinsic.

Question 2

How does each drug category prevent a clot from growing larger?

Categories: anticoagulants, antiplatelets, and thrombolytics.

Answer 2

1. Anticoagulants
   - interferes with clotting cascade and thrombin formation.
2. Antiplatelets
   - inhibits platelet actions and the formation of a platelet plug.
3. Thrombolytics
   - breaks down the thrombus (clot).

Question 3

What is the primary indication of antiplatelet drugs? What is the prototype and mechanism of action?

Answer 3

The primary indication is to prevent clot formation in the arteries.

Prototypes: Aspirin and Clopidogrel

MOA:
- stops platelets from having a platelet party/aggregate in vessel wall.

Question 4

What are the adverse effects of ASA and include the contraindications.

Answer 4

A/E:
- GI (gastric upset, gastric ulcers, gastric bleeding).
- Bleeding (MOST SERIOUS)
- renal impairment
- Salicylism (tinnitus is hallmark sign)
- Reye’s Syndrome

Contraindications: Bleeding/Allergy

Question 5

What is the therapeutic dose for ASA and MOA?

Answer 5

MOA:
- inhibits platelet aggregation by irreversibly inhibiting cox action in platelets.

Therapeutic dose is 81mg

Question 6

The patient is taking ASA 81 mg with a corticosteroid. The nurse knows that they ASA interacts with which drugs?

Answer 6

• Corticosteroids (taking this with an NSAID can lead to peptic ulcers)
• Other drugs that affect clotting
• Other salicylates
• Acetaminophen

Question 7

What is the prototype for ADP Inhibitors and how do they work?

Answer 7

Prototype: Clopidogrel

MOA:
- blocks ADP receptors on platelets
- stops platelet aggregation
- effects last throughout the life of the platelets

Question 8

What would the adverse effects, interactions, and contraindications be for the drug Clopidogrel?

Answer 8

A/E:
- Bleeding
- GI upset, N/V
- Thrombotic Thrombocytopenia Purpura (rare but very serious, you will see scaly, red, flush spots, means that they’re low in platelets)

Interactions:
- several herbs
- other drugs that affect clotting

Contraindicated in bleeding disorders, allergy, thrombocytopenia.

Question 9

What is the traditional drug of choice for rapid anticoagulation? How does this drug work and what is the prototype?

Answer 9

Prototype: Heparin

MOA:
- Factor Xa and Thrombin inhibitor
- Binds with Antithrombin
- Blocks formation of thrombin from prothrombin
- Prevents formation of fibrin clots within minutes of IV administration.

This drug is super effective because it binds with 2 clotting factors. Others only bind with 1.

Question 10

Mr. Smith is a 45-year-old patient currently on a Heparin drip. Which labs will the nurse monitor, how often will they be monitored, and what is the therapeutic range of the labs?

Answer 10

Labs to Monitor: aPTT or PTT

How often: measure daily and 6-8 hours after dosage change.

Therapeutic Range: 1.5-2x the baseline

Question 11

What are the appropriate routes for Heparin and include the adverse effects.

Answer 11

Routes: SC for prophylaxis, IV

A/E:
- Bleeding (Most Serious)
- Heparin Induced Thrombocytopenia
- Hypersensitivity
- Box Warning: it may cause paralysis because of epidural/spinal hematomas.

Question 12

The second shift nurse went to check on her 58-year-old patient. It was time to review the aPTT lab results. The nurse recognizes that the patient’s aPTT is excessively high and the patient is showing signs and symptoms of bleeding. What is the priority action at this point?

Answer 12

Discontinue the heparin drip.

Question 13

What is the antidote to Heparin? Include contraindications and food-drug interactions as well.

Answer 13

Antidote: IV Protamine Sulfate

Contraindications:
- Active Internal Bleeding
- ANYTHING Bleeding
- Severe HTN
- Intracranial Hemorrhage

Interactions:
- Other anticoagulants/antiplatelets
- Several herbs

Question 14

Low Molecular Weight Heparin

What is the prototype? How does the MOA for this drug differ from Heparin itself. What is the route?

Answer 14

Prototype: Enoxaparin

MOA:
- Factor Xa inhibitor only, it does not inhibit thrombin.

Route: SC

Question 15

What are some advantages that would possibly entice others to choose enoxaparin instead of heparin?

Answer 15

It produces a predictable anticoagulant response and there is less lab monitoring. There’s no aPTT/PTT required, but they need a PT/INR.

Question 16

What are the A/E, contraindications, and pregnancy category of enoxaparin? How is the dose determined?

Answer 16

A/E: Bleeding

Contraindicated in active bleeds

Pregnancy Category: B

The dose is based on weight.

Question 17

When caring for a patient that is taking Warfarin (Coumadin), the nurse should expect which labs? How often are they going to be ordered and what is important to know about switching from Heparin to Warfarin?

Answer 17

Labs:
- PT/INR
- An INR of 2-3.5 is a therapeutic
- It is measured daily until the desired level is achieved.
- It is then measured weekly or monthly.

When switching from Heparin to Warfarin it needs to be given concurrently until the INR is therapeutic.

Question 18

What are the therapeutic effects and uses of Warfarin? What is the MOA and route appropriate?

Answer 18

Therapeutic Indications:
- Arterial thromboembolisms
- MI, Stroke, A-Fib, Prosthetic Valves

MOA:
- Stops 2 enzymes involved in the formation of Vitamin K

Route: PO

Question 19

What are the adverse effects of Warfarin? Include contraindications and drug-food interactions as well.

Answer 19

A/E:
- Bleeding
- Osteoporosis/bone fractures with long-term use
- Warfarin toxicity
- Box Warning: It can cause major fatal bleeding

Contraindications:
- Recent Trauma
- Active Internal Bleeding
- Pregnancy (is a category X drug)

Interactions:
- Several Herbs
- Excess intake of foods high in Vitamin K (green leafy veggies in moderation)

Question 20

What is the antidote to Warfarin?

Answer 20

Vitamin K PO or IV

Question 21

How does Rivaroxaban work? What is the appropriate route and what are the adverse effects?

Answer 21

MOA:
- inhibits clotting factors Xa resulting in longer clotting time.

Route: PO

A/E:
- Excessive bleeding
- Box Warning: Abrupt discontinuation can increase the risk for a thromboembolism.

Question 22

What are the contraindications, drug-food interactions, and advantages of rivaroxaban?

Answer 22

Contraindications:
- Anything Bleeding
- Pregnancy (category B)

Interactions: interacts with a lot of drugs

Advantage: INR monitoring is not needed.

Question 23

Thrombolytics

What is the prototype, MOA, and route? What are the therapeutic indications of these drugs?

Answer 23

Prototype: Alteplase

MOA:
- promote fibrinolysis by converting plasminogen to plasmin.
- plasmin digests fibrin breaking it down into small soluble fragments.

Route: IV

Indicated for thrombotic stroke. Off label is to restore IV Cath Patency.

Question 24

Thrombolytic therapy should begin within ____ hours onset of MI symptoms and _____ hours of a thrombotic stroke.

Answer 24

1. Begin within 6 hours of onset of MI symptoms.
2. Begin within 3 hours onset of thrombotic stroke.

Question 25

What are the A/E, contraindications, and drug-food interactions regarding Alteplase?

Answer 25

A/E:
- Very narrow margin of safety
- Need continuous monitoring for bleeding

Contraindications:
- Allergy
- CVA within the past 2 months
- Active Bleed
- Aneurysm
- OB delivery
- Organ biopsy
- Cerebrovascular Disease

Interactions: anticoagulants and antiplatelets

Question 26

Which drugs are antiplatelets?

Answer 26

ASA and Clopidogrel

Question 27

Which drugs are anticoagulants?

Answer 27

Heparin, Enoxaparin, Warfarin, and Rivaroxaban.

Question 28

Which drug is a thrombolytic agent?

Answer 28

Alteplase