Drugs That Affect The Blood Coagulation: Hematologic Agents

Drugs that Affect the Blood Coagulation

Hematologic Agents

Anticoagulants • • • • •

“prevent thrombus (blood clot) formation” Effective in preventing venous thrombosis Prevent clot formation/extension Do not dissolve clots Increase blood flow to prevent necrosis; interfere with clotting process Most common: Heparin & Coumadin

Heparin sodium • MOA: inhibits conversion of fibrinogen to fibrin by activating antithrombin II = prevents a stable fibrin clot • Indications: • Prophylaxis / Tx of thromboembolic disorders – Deep Vein Thrombosis (DVT) – Pulmonary emboli (PE) • Maintain IV patency (IV flush) • Drug of choice for orthopedic surgeries • Post-op prolonged bed rest (>5days) • Prevents clots r/t artificial heart valves • Treats Disseminated Intravascular Coagulation (DIC) widespread clotting depletes coagulation factors; Heparin slows the process to rebuild factors

Adverse effects • • •

Hemorrhage Thrombocytopenia Pain at injection site

Drug Interactions • Increased risk of bleeding – ASA “antiplatelets” – Thrombolytic agents

• Increased anticoagulant effect •

– Digitalis Long-term use – Alopecia – Osteoporosis

Precautions •Contraindications: »Active hemorrhage »GI ulcers »Liver or kidney disease »Recent eye surgery

Low Molecular Weight Heparins (LMWHs) •enoxaparin (Lovenox) •dalteparin (Fragmin) •No daily monitoring of labs •Uses: – Outpatient therapy – Treats DVT – Ml w/ASA promote cardiac circulation – Complications r/t unstable angina

Nursing Interventions • Health Hx (bleeding disorders or potential risks) • Monitor labs • partial thromboplastin (PTT) PTT is 1.5 - 2.5 times the “normal” value (daily when continuous IV infusion) • Platelet counts

• Assess for bleeding - gums, GI bleed (guaiac + stools) • Admin SC lower abdomen; “No” IM injections • Antidote is Protamine Sulfate for heparin overdose • Nomogram (sliding scale for heparin infusion based on lab studies)

Patient Education • • • • • •

Wear Medic Alert Follow-up appts; labs Notify providers of bleeding Avoid razors Avoid ASA or other antiplatelets Dietary: vitamin K alters effectiveness

warfarin sodium (Coumadin) • MOA: alters the liver’s ability to synthesize Vitamin K dependent clotting factors; no effect on circulating clotting factors or platelet function • Admin orally; effects after 3-5 days • Indications: • Long term prevention of thromboembolic disorders – Deep Vein Thrombosis (DVT) – Pulmonary emboli (PE) • Manage MI to reduce risk of death, recurrent MI

• Contraindications: • Gastric ulcers • Recent eye or spinal cord surgery

Coumadin con’t • • • •

Cramps / nausea with initial dose Begin admin while heparin is being admin IV Antidote is Vitamin K IM for overdose Monitor prothrombin time (PT) 1-1.5 times the normal • Monitor International Normalized Ratio (INR) • Monitor for bleeding • Dietary teaching avoid foods high in vitamin K – leafy green vegetables (spinach, mustard greens etc…)

Antiplatelets prevent arterial thromboembolism • MOA: interfere with initial phase of blood coagulation; inhibits platelet aggregation • Uses: • Prevent MI • Stroke in clients w/ TIA (transient ischemic attacks) • Thromboemboli in pts w/ artificial heart valves

• Adverse effects: • Increased bleeding • GI bleeding, dyspepsia

Important Drugs • ASA • • • •

Analgesic/antipyretic Inhibit prostaglandins Reduces TIA Small doses

• dipyridamole (Persantine) • Recommended for use after cardiac valve replacement admin with Coumadin; dilates coronary arteries

• ticlopidine (Ticlid) • Prevents strokes in person w/ a history of stroke (CVA) who are unable to tolerate ASA

• abciximab (ReoPro) • Admin with percutaneous transluminal coronary (PCTA) angioplasty to prevent rethrombosis; given w/ASA &

Nursing Interventions & Pt. Education • • • • • • • •

Monitor VS routinely EKG Assess for symptoms of stroke Monitor labs bleeding times, CBC q2weeks for 3 months Admin after meals w/full glass of water; antacid to decrease gastric irritation Report tinnitus, unusual bleeding Avoid ETOH use Follow up visits especially during the first 3 months

Thrombolytic agents • • • •

altepase (Activase) streptokinase (Streptase) Meds used to dissolve a preexisting clot Used in acute and emergency situations • Tx MI to re-perfuse myocardium • Reestablish blood flow in arteriovenous cannulas (dialysis) • central venous catheters

• Admin in intensive care units • Lyse (dissolve) thrombi