Other

NR566 Week 5 Study Outline Chapter 18: Drugs Affecting the Hematopoietic System

16 views 0 purchase

Course
AIT Nursing (NR566)

Institution
Thompson River University (TRU )

[Show more]

Preview 4 out of 44 pages

View example

Uploaded on February 11, 2021
Number of pages 44
Written in 2020/2021
Type Other
Person Unknown

anticoagulants
nr566 week 5 study outline
nr566 week 5 study outline chapter 18 drugs affecting the hematopoietic system
• pharmacodynamics • oral anticoagulants such as warfarin coumadin inhibit

Welch1 Member since 6 year 61 documents sold

CA$20.09

Added

Add to cart Add to wishlist

100% satisfaction guarantee
Immediately available after payment
Both online and in PDF
No strings attached

NR566 Week 5 Study Outline
Chapter 18: Drugs Affecting the Hematopoietic System
• Know the pharmacodynamics, pharmacotherapeutics clinical use, drug interactions and adverse drug
reactions for:

Anticoagulants

• Pharmacodynamics
• Oral anticoagulants such as warfarin (Coumadin) inhibit the hepatic synthesis of several clotting factors,
including factor X.
• Heparin inhibits the activity of several activated clotting factors by accelerating the activity of
antithrombin III.
• LMWH enoxaparin (Lovenox) potentiates the activity of antithrombin III and inactivates factors Xa and
IIa (thrombin).
• Dabigatran (Pradaxa) is a direct thrombin inhibitor.
• Thrombin is required for the conversion of fibrinogen to fibrin in the clotting cascade, thus dabigatran's
inhibition of thrombin prevents thrombi from forming.
 Fondaparinux (Arixtra) is a selective inhibitor of antithrombin III and a factor Xa inhibitor.
 Rivaroxaban (Xarelto) an anticoagulant, is a highly selective factor Xa inhibitor that inhibits thrombin
formation and the development of thrombi.
 Apixaban (Eliquis) is a selective inhibitor of factor Xa.
• Aspirin antagonizes the cyclooxygenase pathway and interferes with platelet aggregation.
• NSAIDs have this same action.
• NSAIDs are not used as antiplatelet drugs, but this explains why concurrent use with
anticoagulants is contraindicated
• Ticlopidine (Ticlid) and clopidogrel (Plavix) reduce platelet aggregation by inhibiting the ADP pathway
of platelets.
• Unlike aspirin, they have no effect on prostaglandin metabolism.
• Ticagrelor (Brilinta) reversibly interacts with the platelet P2Y12 ADP-receptor to prevent platelet
activation.
• Vorapaxar (Zontivity) is a protease-activated receptor-1 (PAR-1) antagonist, inhibiting thrombin-
induced and thrombin receptor agonist peptide-induced platelet aggregation

• Pharmacotherapeutics:

• Precautions and Contraindications
• All anticoagulants are contraindicated for patients who are hypersensitive to the drug or actively
bleeding or who have hemophilia, thrombocytopenia, severe HTN, intracranial hemorrhage, infective
endocarditis, active tuberculosis, or ulcerative lesions of the GI tract.
• Heparins are contraindicated in advanced hepatic or renal disease.
• They may be used in patients who are actively bleeding to treat DIC
• Heparin is Pregnancy Category C: stillbirth, prematurity
• Some heparin preparations contain benzyl alcohol: known to cause “gasping syndrome”:
• fatal toxicity in neonates
• Hyperkalemia may develop
• Use for patient with DM or renal insufficiency requires care and frequent monitoring of aPTT

, • Has been associated with fatal medication errors r/t different strengths of preparations
• JCo: anticoagulant therapy is a National patient Safety Goal: plan in place at each facility to
reduce patient harm
• LMWHs are contraindicated for patients with allergies to pork, sulfites, or benzyl alcohol; uncontrolled
bleeding; and in patients who have antiplatelet antibodies
• Renal impairment: cautious use
• Body weight less than 50 kg associated with increased r/f bleeding:
• enoxaparin dose adjustment
• Cautious use: untreated HTN, retinopathy (HTN or DM caused), severe liver disease, recent Hx
of ulcer, or malignancy
• Not used for thromboprophylaxis in patients with mechanical heart values: especially pregnant
(r/f heart value thrombosis)
• Enoxaparin: Preg Cat B, tinzaparin: teratogenicity and fetal death, fondaparinux: Preg B
• First line drug for women who require antithrombotic therapy during pregnancy: LMWH
• Pharmacokinetics of LMWH is altered during pregnancy
• Warfarin
• Hepatic dysfunction potentiates response through impaired synthesis of coagulation factors
• Use with caution: Hypermetabolic states produced by fever or hyperthyroidism increase
responsiveness to warfarin:
• r/t increased catabolism of vit K dependent coagulation factors
• Increased r/f bleeding in older adults
• Caution use based on balance between potential for decreased r/f thromboembolism and
the risk for bleeding especially in those with dementia or severe cognitive impairment:
Hx of three falls in the previous year or recurrent injurious falls, uncontrolled HTN, or
non-adherent or unreliable
• Warfarin is Pregnancy Category X: Crosses placenta and can cause hemorrhagic disorders in
the fetus and serious birth defects
• Safe during lactation
• Rivaroxaban (Xarelto): Black-Box Warning: premature discontinuation of anticoagulants including
rivaroxaban may lead to thrombotic events.
• An increased risk of stroke is seen in patients with atrial fibrillation when transitioning to
warfarin
• Rivaroxaban is Pregnancy Category C and is not recommended for use in pregnant women.
• Apixaban (Eliquis): Black Box warning premature discontinuation leading to thrombotic events
• Although there are no well-controlled studies: Pregnancy Category B
• Hypersensitivity to aspirin and cross-sensitivity with NSAIDs may occur, contraindicating the drug
• Aspirin hypersensitivity is more prevalent in patients with asthma, nasal polyps, or chronic
urticaria.
• Reye syndrome has been associated with its use in children and teenagers who have influenza or
chickenpox.
• Reversible hepatotoxicity has occurred
• Use with caution in liver damage, preexisting hypoprothrombinemia, or vit K deficiency
• Preg Cat C and Cat D in third trimester
• Avoid during lactation
• Clopidogrel and ticlopidine: severe hepatic disease (r/f bleeding d/o), do not use in these patients
• Not recommended for patients with GI d/o
• Preg Category B
• Ticlopidine: clearance increased with age, older adults increased sensitivity to this drug (closely
monitor or ADRs)
• Older adults: increased levels of clopidogrel: no dosage adjustments

, • In older adults clopidogrel is a safer drug
• Ticlopidine: elevations in cholesterol and TC within 1 month of therapy: factor in HLD
• Ticagrelor: Black-Box Warning to not use in a patient with active pathological bleeding or history of
intracranial hemorrhage.
• Ticagrelor should be discontinued 5 days prior to any surgery.
• Dabigatran: Black-Box Warning concerning discontinuation increasing risk of thrombotic events.
• There is no reversal agent available for dabigatran
• Vorapaxar: Black-Box Warning to not use in patients with a history of stroke, TIA, intracranial
hemorrhage, or active pathological bleeding.
• Vorapaxar is Pregnancy Category B, with no congenital malformations found in animal studies

• ADRs
• All anticoagulants: excessive bleeding
• Risk is higher early in therapy, with wide fluctuations in aPTT or INR, and older adults
(especially women over 60)
• Heparins: cause thrombocytopenia and anemia
• More likely with bovine than with porcine
• Early thrombocytopenia 2 to 3 days after starting therapy and delayed forms 7 to
12 days
• Platelet below 100,000: d/c heparin
• Enoxaparin antidote: protamine sulfate 1 mg for each mg of enoxaparin
dalteparin and tinzaparin: 1 mg for each 100 anti-Xa IUs of dalteparin
• Slow IV injection
• Fondaparinux: no known antidote
• Heparin has a short half-life: Tx is usually d/c of the drug
• Protamine sulfate antidote for heparin OD
• Warfarin: toxicity and OD Tx withholding one or more doses
• Or 1 to 10 mg of vitamin K is the antidote for minor bleeding
• 5 to 50 may be used for frank bleeding
• Hemorrhagic skin necrosis in women and cyanotic toes in men have been reported
• r/t transient inhibition in proteins S and C
• Allergic reactions: symmetrical, maculopapular, erythematous lesions
• Some are isolated and some confluent: face, neck, and torso
• May not appear until 8 to 10 days
• Ribaroxaban: bleeding is major ADR
• No reversal agent
• Back pain, upper ABD pain, osteoarthritis, dyspepsia, and fatigue
• Apixaban: bleeding
• No reversal agent
• ASA: gastric erosions: increased r/f serious upper GI bleeding
• More likely when used in combo with other anticoags such as warfarin
• Salicylism (tinnitus) : serum levels above 200 mcg/mL
• Toxicity: tinnitus, HA, hyperventilation, agitation, confusion, lethargy, diarrhea, and
sweating
• Ticagrelor: bleeding
• Dyspnea: sometimes improves with use or must be d/c
• HA, cough, dizziness, and nausea
• Ticlopidine: reversible neutropenia at 3 weeks to 3 months after initiation of therapy
• Severe neutropenia (<450) or thrombocytopenia (<80,000) d/c drug
• Clopidogrel: ADRs similar to ASA, safe and effective

, • Dabigatran: bleeding
• GI ADRs: dyspepsia and gastritis-like symptoms
• Angioedema and thrombocytopenia
• Vorapaxar: bleeding
• Anemia, depression, and rashes or eruptions

• Drug Interactions
• Cephalosporins and PCNs given parenterally associated with coagulopathies, increased r/f bleeding
when given with Heparin
• Second and third gen cephalosporins and high doses of PCNs: increased r/f bleeding with Warfarin
• Drugs that affect platelet functioning or cause hypoprothrombinemia (ASA, NSAIDS, dipyridamole,
quinidine, and valproic acid: increased r/f bleeding
• Heparin and LMWHs: similar drug interactions: also interact with antiplatelets including NSAIDS and
dextran
• Foods can effect anticoags
• Warfarin: many drug interactions and increased INR monitoring within 4 to 7 days when other drugs are
started or stopped even ABX
• Vit K: antagonistic interaction with warfarin: decreases effectiveness
• Inhibitors of CYP 1A2, CYP 2C9, or CYP 3A4 increase effect of warfarin
• Inhibitors decrease the effectiveness of warfarin
• Interacts with any other drug that increased bleeding: anticoags, antiplatelets, NSAIDS and
SSRIs
• ABX and antifungals may affect INR
• Herbal Productions may increase bleeding: ginkgo biloba and garlic
• Decrease effectiveness: St John’s wort, ginseng, and coenzyme Q10
• May influence metabolism of warfarin: St John’s wort, echinacea, ginkgo, goldenseal, AND
GRAPEFRUIT JUICE
• Dabigatran: rifampin (decreased levels of dabigatran)
• Dronedarone increased dabigatran levels by 70 to 150%
• CCB verapamil: increases dabigatran
• Amiodarone increases dabigatran
• Clopidogrel increases dabigatran
• Ticagrelor: metabolized by CYP 3A4: avoid strong inhibitors ketoconazole, itraconazole, voriconazole,
clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, atazanavir, and telithromycin
• Avoid inducers: rifampin, dexamethasone, phenytoin carbamazepine, and phenobarbital
• Vorapaxar: avoid with CYP3A inhibitors
• Avoid use of inducers (rifampin, carbamazepine, St John’s Wort, and phenytoin

• Clinical Use and Dosing

Prevention and Treatment of Thromboembolism
• Warfarin: drug of choice for prevention of venous thrombosis, systemic thrombosis, and pulmonary
embolism
o For prevention: give dose sufficient for INR between 2 and 3
o Beginning dose is 10 mg daily for the first 2 days with a recheck of INR in two to three doses
o ICSI guidelines: recommend starting warfarin at 5 mg/day with a range of 2.5 mg to 7.5 mg/day
o Further dosing is based on INR
o Lower initiation doses for:
 Older than 75

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller Welch1. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for CA$20.09. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

81113 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 14 years now

Start selling

Other

NR566 Week 5 Study Outline Chapter 18: Drugs Affecting the Hematopoietic System

Document information

Subjects

Written for

Seller

Reviews received

Content preview