Anticoagulants, Antiplatelets, Thrombolytics Flashcards
in plasma
H2O and electrolytes (Sodium, magnesium, potassium), proteins (albumines, globulino, fibrogen), wastes, nutrients (vitamins, hormones), gases (O2, N2, CO2)
formed elements
platelets, red blood cells, white blood, cells
white blood cell types
neutrophils and monocytes are the 1st to site; eosinphils and basophils are for allergic reaction; lymphocytes - immunity
thrombus =
clot
Anticoagulants, Anti-platelets, Thrombolytics are used to treat
THROMBOTIC and THROMBOEMBOLC disorders
Embolus
traveling clot (so it breaks loose and travels)
THROMBI and EMBOLI that lodge in vital organs can cause
death
How Clotting Occurs
When injury to a blood vessel occurs, within seconds, PLATELETS travel to the site and within 1-2 minutes, form a platelet plug to stop the bleeding; • The platelet cell membrane immediately begins to disintegrate allowing contents to leak that cause VASOCONSTRICTION; and Release of THROMBOPLASTIN
THROMBOPLASTIN with calcium ions causes the conversion of PROTHROMBIN to **
THROMBIN
THROMBIN converts FIBRINOGEN to **
FIBRIN
After 24 hours, FIBRIN replaces
platelets at the site of the blood clot
so goal to prevent the release of thromboplastin so you would need
anticoagulant
anticoagulants DO NOT
DO NOT dissolve clots; DO NOT improve blood flow in the surrounding tissue of the clot; DO NOT prevent ischemic damage to tissues beyond the clot; DO NOT “thin” the blood
anticoagulants are given to
PREVENT CLOT EXTENSION AND FORMATION (so given to prevent clot formation)
“By definition, anticoagulants are drugs
that reduce formation of fibrin.”
2 TYPES OF ANTICOAGULANTS
- Parenteral Heparins 2. Oral warfarin (Coumadin)
anticoagulants are different than anti platelets by working on
clotting factors not the platelets
Parenteral Heparins inhibits **
thrombin, thus blocking conversion of fibrinogen to fibrin
Parenteral Heparins helps
antithrombin inactivate clotting factors, thrombin and factor Xa
now draw blood to check
anti Xa levels for people on heparin
all heparins are given
parenterally - subq or IV
Oral warfarin (Coumadin) blocks
the synthesis of vitamin k-dependent clotting factors
vitamin k
helps make clotting factors
Oral warfarin (Coumadin) acts as
as a competitive antagonist to hepatic use of Vitamin K
so if decrease vitamin k then
decrease clotting factors
Heparin is great for
emergencies because it has a very short half life
Heparin MOA
Inhibits thrombin–mediated conversion of fibrinogen to fibrin AND inhibits active factor X
Heparin is metabolized and excreted by
Metabolized in liver, excreted by kidney
half life of heparin
Half life of 1-2 hours; increases with increasing dosage
heparin does not cross _______ and not secreted in ________
Does not cross placental barrier; not secreted in breast milk
Heparin: Uses/Indications
Prophylaxis and treatment of clots; Maintains patency of catheters; Prevents clotting during surgery or vascular procedures; Prevents clotting around prosthetic heart valves
Prophylaxis and treatment of clots with heparin
Deep vein thrombosis; pulmonary emboli; Atrial fibrillation with clots
adverse effects of heparin
BLEEDING; Anemia, thrombocytopenia; Local pain or discomfort at subcutaneous injection site; Long term use: alopecia, osteoporosis
so if any pt on heparin use what
bleeding precautions ex. apply pressure longer
(interaction of heparin) Increased bleeding if used concurrently with:
anti-platelet drugs: aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs); clopidogrel (Plavix); quinidine, cephalosporins; thrombolytic drugs
(interaction of heparin) • Anticoagulant effect may be INCREASED if heparin combined with:
digoxin, tetracyclines, nicotine and alcohol, antihistamines
Contraindications- Do not use heparin if:
Active Bleeding; Gastrointestinal ulcers; Hemophilia, thrombocytopenia; Severe liver or kidney disease; Uncontrolled hypertension; Recent CNS surgery, spinal cord injury, brain surgery; Recent eye surgery
Use Heparin Cautiously if:
Mild hypertension; Severe diabetes; Renal or hepatic disease; Alcoholism; Presence of drainage tubes; Malignancy; Last trimester of pregnancy or immediate
with Heparin check pt’s history for
for bleeding disorders or any pre-existing condition that would increase risk for bleeding
Check activated partial thromboplastin time (aPTT):
Normal value is 40 seconds. At therapeutic levels, heparin INCREASES the aPTT by a factor of 1.5 to 2 times
On heparin therapy, the aPTT should be
60-80 seconds (prolonged aPTT
If aPTT is too long (>80 seconds), the heparin dose should be
decreased (pt has too much heparin, put infusion on hold for a few hours and resume at a lower rate)
If aPTT is 50 seconds, the heparin dose should be
increased (great risk for clotting so increase dose)
If patient is bleeding excessively or aPTT is extremely prolonged
Stop the heparin; Administer Protamine sulfate: antidote or antagonist for heparin-neutralizes heparin activity
for pt on heparin assess pt for
bleeding gums, nosebleeds, unusual bruising , hematuria, guaiac-positive stools, prolonged bleeding from needle puncture sites, or wounds.
for pt on heparin avoid
needle sticks; apply pressure for 2 minutes for venous sticks; 5minutes for arterial sticks
for pt on heparin monitor for low
hemoglobin hematocrit, platelet counts
When administering SC heparin
use 25-26 gauge needles, administer 2 inches from umbilicus in abdomen, do not aspirate or apply pressure.
pt teaching with heparin
Use soft bristled tooth brush, electric shavers only, protective gear with physical activity; Wear Medic Alert identification; Avoid vigorous activities leading to injury that might cause bleeding
Low Molecular Weight Heparins
Lovenox (enoxaparin), Innohep
Low Molecular Weight Heparins are
• Molecules shorter than regular heparin; have greater bioavailability and longer half-lives
with Low Molecular Weight Heparins plasma levels are
predictable** for any given dose: do not require laboratory monitoring although will increase activated partial thromboplastin time
Low Molecular Weight Heparins have less risk of
bleeding: safe for outpatient use
Low Molecular Weight Heparins work mostly at inactivating
factor Xa rather than thrombin; response more stable and effect two to four times longer than that of heparin
Low Molecular Weight Heparins cost
more than twice that of heparin
Low Molecular Weight Heparin are the first line therapy for
prevention and treatment of deep vein thrombosis
Low Molecular Weight Heparins can cause severe
neurologic injury (paralysis) when given to patients undergoing spinal puncture or epidural anesthesia
