Pharmacology

when a blood vessel is injured a series of events occurs to form a clot and stop the bleeding.

Formation of a blood clot

DVT usually occur in the lower ext and most common type is venous thrombosis

Atherosclerosis or arrhythmias, such as atrial fibrillation.

Its when a thrombus detaches itself from the wall of the vessel and is carried along through the bloodstream.

the embolus goes to the lung and obstructs a pulmonary vessel

• prevent the formation and extension of a thrombus IN THE VENOUS SYSTEM. They are also called blood thinners.
• Peak activity is reached 1.5 to 3days after therapy is started.

• Anticoagulants:
• Oral = anisindione, warfarin sodium,
• Parenteral = heparin (based on weight) MIRADON, heparin sodium lock flush solution COUMADIN
• parental anticoagulants: Low-molecular-weight-weight heparins(LMWH) = dalteparin sodium FRAGMIN, enoxaparin soduim LOVENOX, tinzaparin sodium INNOHEP

• they interfere w/ the clotting the clotting mechanism of the blood.
• warfarin and anisindione interfere with the manufacturing of vitamin k-dendent clotting factors by the liver. This results in the depletion of clotting factors II(prothrombin) which is ESSENTIAL 4 clotting

Nurse = Heparin cant be taken orally cuz its inactivated by gastric acid in the stomach so it has 2 be injected.

• Prevention of
• Prophylaxis and tx of DVT
• Tx of atrial fibrillation w/ embolization
• Tx of PE
• Adjuvant tx of MI
• Prevention of thrombus formation after valve replacement surgery

• Parenteral anticoagulants used 4:
• prevention of postop DVT and PE in certain pts hving surgery like ABD surgery.
• prevention of clotting in arterial and heart surgery, equipment used 4 extracorporeal, dialysis procedures, blood transfusions, blood samples 4 lab.
• prevention of repeat cerebral thrombosis pts who had a stroke
• tx of coronary occlusion, acute MI, peripheral arterial embolism
• dx & tx of DIC, severe hemorrhagic disorder
• maintaining patency of IV caths

Bleeding may be seen in many areas of the body ex bruising and petechia, bladder, bowel, stomach, uterus, and mucous membranes.

• Other a/r but rare:
• nausea, vomiting, abd cramping, diarrhea
• alopecia
• rash or urticaria
• hepatitis, jaundice, thrombocytopenia, blood dyscarasias (disorder)

• Most serious a/r:
• asthma-like reactions and anaphylactic reaction

nurse = make sure you know if they are allergic to PORK cuz LMWHs are contraindicated in peeps allergic 2 PORK

Contraindications:

• active bleeding (except when caused by DIC)
• hemorrhagic disease
• TB
• Leukemia
• uncontrolled hypertension
• GI ulcers
• Recent surgery of eye or central nervous system, aneurysms
• Severe renal or hepatic diseas
• PORK ALLERGIES

Precautions:

• fever
• heart failure
• diarrhea
• diabetes
• malignancy
• hypertension
• renal or hepatic disease
• psychosis
• depression
• CAUTION IN PEEPS W/ POTENTIAL BLEEDING OR HEMORRHAGE
• AND TELL CHICKS WHO CAN GET PREGO 2 USE RELIABLE BIRTH CONTROL

prevent thrombus formation in the ARTERIAL SYSTEM.

• Antiplatelet drugs
• abciximab (reopro), cilostazol (pletal), clopidogrel (plavix), eptifibatide (integrillin), ticlopidine (ticlid), tirofiban (aggrastat), treprostinil (remodulin)

• Decrease platelets' ability 2 stick 2gether (aggregate) in the blood so stopping a forming clot
• Tx patients @risk 4 acute coronary syndrome, MI, stroke, and intermittent claudication

Common a/r

• heart palpitations
• bleeding
• dizziness and headache
• nausea, diarrhea, constipation, dyspepsia

• Pregos or lactating
• CHF
• active bleeding
• TTP (thrombotic thrombocytopenic purpura)

Caution in:

• Elderly
• pancytopenic patients
• renal or hepatic impairment

Nurse = antiplatelet drugs should be stopped 1wk b4 any surgical procedure.

• these class of drugs dissolves blood clots that have already formed within the walls of the blood vessel.
• Reopen blood vessels after they bcome occluded

Thrombolytic aka fibrolytic drugs:

alteplase recombinant (activase), reteplase recombinant (retavase), streptokinase (streptase), tenecteplase (TNKase), urokinase (abbokinase)

• Actions:
• break down fibrin clots and reopens blood vessels after occlusion and prevents tissue necrosis

Uses:

• Acute MI by lysis(break up) of blood clots in coronary arteries
• Blood clots causing PE and DVT
• Suspected occlusions in central venous catheters

Bleeding most common can be internal and involve GI tract, genitourinary tract and brain and can be external like broken skin

Nurse = signs and syptoms of internal bleeding LOW B/P, HEMO &HCT LOW, WEAKNESS IN PT.

Contraindicated:

• active bleeding
• history of stroke
• aneurysm
• recent intracranial surgery

Precautions:

• peeps who recently undergone major surgery (w/in 10days)
• stroke
• trauma w/in last 10days
• vaginal or cesarean section delivery
• GI bleeding
• hypertension
• diabetic retinopathy
• any bleeding condition and peeps using oral anticoagulants

Nurse:

• Question pt about all drugs taken during the previous 2 to 3wks
• Take PT, INR and asses result b4 drug is given cuz dose is based on results
• Vital signs
• In heparin monitor activated partial thromboplastin time(APTT)
• In DVT peeps look @ lower ext 4 color or skin temp, pedal pulses, redness tenderness, chk 4 homan's sign suggests DVT
• CBC

Nurse:

• assess 4 any signs of bleeding and hmorrhage inspect gums, nose, stools, urine, nasogastric drainage
• Level of conciousness if hv intracranial bleeding
• Withhold drug if PT exceeds 1.2 to 1.5x the control value or the INR ratio exceeds 3
• Monitor periodic platelet counts, hematocrit and tests 4 occult blood in stool should be performed thruout therapy
• Monitor & report reactions like chills, fever, hives
• take v/s every 4hrs
• Observe 4 signs of thrombus formation every 2to4hrs

NURSE:

• b4 giving warfarin check the prothrombin flow sheet or lab rpt 2 review current PT/INR results
• Loading dose may be prescribed for 2to 4days
• Know that these drugs take 3 to 5 days to reach therapeutic effects
• HEPARIN is preferred as a loading dose

Nurse know

• heparin preparations, unlike warfarin must be given by SC or IV
• Maximum effects occur w/in 10mins of administration and clotting time returns 2 normal w/in 4hrs unless more doses are given
• Infusion pump must be used 4 safe administration of heparin by continuous IV and chk it every 1 to 2hrs
• Check needle site