Anticoagulants

Question 1

Heparin

Answer 1

Adverse effects:
can produce hemorrhage from any body site
Tissue irritation/pain at injection site, Fever
Anemia, thrombocytopenia

Considerations:
Monitor therapeutic partial thromboplastin time (PTT) at 1.5-2.5x control without sx of hemorrhage
Lower limit of nml 20-25 sec, upper limit 32-39 sec
For IV admin, use pump. Peak 5 min, duration 2-6h
For injection: DEEP SQ, NEVER IM (danger of hematoma), onset 20-60 min, duration 8-12h
ANTIDOTE: PROTAMINE SULFATE within 30 min
Can be allergenic

Question 2

Enoxaparin

Low molecular weight heparin

Answer 2

Action: blocks conversion of fibrinogen to fibrin

Use: prophy and tx of thromboembolic disorders.
In very low doses (10-100 units) to maintain latency of IV catheters (heparin flush)

Adverse:
can produce hemorrhage from any body site
Tissue irritation/pain at injection site, Fever
Anemia, thrombocytopenia

Considerations:
Less allergenic than heparin
MUST BE DEEP SQ, NEVER IM/IV

Question 3

Warfarin

Answer 3

Action: interferes with liver synthesis of Vitamin K dependent clotting factors

Use: management of pulmonary embolism, venous thromboembolism, MI, atrial dysrhythmias, post cardiac valve replacement

Adverse: hemorrhage, diarrhea, rash, fever

Considerations:
monitor therapeutic prothrombin time (PT) at 1.5-2.5x the control* or monitor INR.
Nml PT 9.5-12 sec, nml INR 2.0-3.5
Onset 12-24h, peak 1.5-3 days, DURATION 3-5 DAYS
ANTIDOTES: VITAMIN K, WHOLE BLOOD, PLASMA
Teach measures to avoid venous stasis
REGULAR LAB TESTING
Avoid foods high in vitamin K: green vegetables, pork, rice, yogurt, cheeses, fish, milk

Question 4

Anticoagulants - general action/indication

Answer 4

Action:
Heparin: blocks conversion of fibrinogen to fibrin
Warfarin: interferes with liver synthesis of vitamin K-dependent clotting factors

Indications:
Heparin: prophylaxis and txt of thromboembolic d/o’s. In very low doses (10-100 units) to maintain potency of IV catheters (heparin flush)
Warfarin: mgmt of pulmonary embolism, venous thromboembolism, MI, atrial dysrhythmias, post cardiac valve replacement
Dipyridamole - as adjunct to warfarin in postop cardiac valve replacement, as adjunct to aspirin to reduce the risk of repeat stroke of TIAs

Adverse effects: nausea, allowed is, urticaria, hemorrhage, bleeding/heparin-induced thrombocytopenia

Question 5

Anticoagulants - nursing considerations

Answer 5

Check for sx of hemorrhage: bleeding gums, nosebleed, unusual bleeding, black/tarry stools, hematuria, fall in Hct or BP, guaiac positive stools
Avoid IM injections, ASA-containing products, NSAIDs
Wear med alert tag
Soft toothbrush, electric razor, report bleeding gums/petechiae/bruising/epistaxis/black tarry stools
Monitor PLT counts and s/sx thrombosis during heparin therapy.
If HIT suspected, heparin discontinued and non-heparin anticoagulant given

Question 6

Anticoagulants herbal + vitamin interactions

Answer 6

GARLIC, GINGER, GINGKO, GINSENG - may increase bleeding when taken with warfarin
ANISE and ALFALFA interfere/decrease anticoagulant activity
Black haw increases anticoagulant
Chamomile interferes with anticoagulants

Vitamins:
Vitamin C may slightly prolong PT
Vitamin E will increase warfarin’s effect