CV Drugs (III)

Thrombus

stationary blood clot from aggregation of fibrin, clotting factors, and cells, forming at a damaged vessel wall; can block blood flow

Deep Vein Thrombosis (DVT)

a thrombus in a deep vein (e.g. iliac, femoral), causing pain, swelling, and risk of embolism

Thrombophlebitis

clot with vein inflammation

Embolus

dislodged thrombus traveling in the bloodstream; can block vessels in lungs (PE), or heart (stroke)

Anticoagulant

substance to prevent or delay coagulation of blood or inhibit enlargement of clot

Fibrinolytic

substance to prevent the formation of a platelet plug; defends body against heart attacks and strokes

Thrombolytic

substance to dissolve blood clots

Hemostatic agents

substance to promote coagulation

Prothrombin Time (PT)

evaluates adequacy of extrinsic system and common pathway in clotting mechanisms (factors I, II, V, VII, X)

Activated Partial Prothrombin Time (aPTT)

evaluate adequacy of intrinsic system and common pathway in clotting mechanisms (factors I, II, V, VIII, IX, X, XI, XII)

International Normalized Ratio (INR)

PT ratio of test sample compared to normal PT (normal 1.0-2.0)

Prototype of Anticoagulants

Heparin, Enoxaparin (Lovenox)

MOA of Heparin

Activates antithrombin III, inhibits thrombin and factor Xa → prevents new clots from forming (not existing clots)

Indications of Heparin

DVT, MI, PE prophylaxis

Nursing Concerns of Heparin

Checks aPTT every 6 hours; loading dose → continuous IV infusion; used acutely for existing clots

Antidote for Heparin

Protamine sulfate if bleeding occurs

Nursing Concerns of Enoxaparin (Lovenox)

• Used as prevention and treatment of clots (post surgery and at home)

• Dosing based on weight

• SubQ

• Never give with heparin (excessive bleeding)

Prototype of Oral Anticoagulants

Warfarin (Coumadin)

MOA of Warfarin (Coumadin)

Blocks enzymes that activates vitamin K, reduces production of vitamin-K dependent clotting factors (II, VII, IX, X) → prevents new clots but doesn’t dissolve existing clots

Indications of Warfarin (Coumadin)

• Used longterm after MI, PE, DVT to prevent clot formations

• Heparin used first until warfarin is therapeutic, continued after for home use

Antidote for Warfarin (Coumadin)

Vitamin K (Aqua-MEHPHYTON)

Nursing Concerns for Warfarin (Coumadin)

• Check PT/INR everyday until discharge, weekly or biweekly after

• Monitor for bleeding

• Use soft toothbrush

• Avoid OTC (aspirin, NSAIDs)

• Diet caution for vitamin K

Prototype for Antiplatelet Agents

Acetylsalicyclic Acid (Aspirin, ASA)

MOA of Acetylsalicyclic Acid (Aspirin, ASA)

Inhibits COX-1 (low) and COX-2 (high) enzymes, reducing thromboxane A2 formation → reduces platelet aggregation (clumping) and prevents vasoconstriction

Indications of Acetylsalicyclic Acid (Aspirin, ASA)

Low Dose (81mg/day) → Prevention of heart attacks or stroke

Medium dose (162-325mg/day) → Used during acute MI (immediate antiplatelet effect) 

Nursing Concerns for Acetylsalicyclic Acid (Aspirin, ASA)

• Watch for subclinical bleeding (petechiae, ecchymosis)

• GI bleeding or hemorrhage risk (take with food or enteric-coating)

• Avoid combining with other anticoagulants or NSAIDs (increased bleeding risk)

Prototype for Thrombolytic Agents

Altepase (Activase)

MOA of Altepase (Activase)

Converts plasminogen → plasmin; breaks down fibrin clots, clotting factors (V and VIII) and lowers fibrinogen; enhances clot breakdown

Indications for Altepase (Activase)

Used in life-threatening clots (stroke, MI, massive PE) for rapid clot removal

Nursing Concerns for Altepase (Activase)

• Major risk is severe bleeding

• IV used in critical care setting; continuous monitoring of vitals and hemodynamics

Prototype of Hemostatic Agents

Aminocaproic Acid (Amicar)

MOA of Aminocaproic Acid (Amicar)

Binds to plasminogen and plasmin, blocking ability to break down fibrin clots → helps stabilize clot and prevent clot dissolution

Indications of Aminocaproic Acid (Amicar)

Used to control excessive bleeding (post-op cardiac surgery, aplastic anemia)

Nursing Concerns for Aminocaproic Acid (Amicar)

Watch for extravasation (leaking at IV site) and thrombophlebitis

Monitor closely for signs of clot formation or reduced circulation

Triglycerides

main form of stored fat in adipose tissue; major energy source

Cholesterol

produced by liver; used to make hormones, vitamin D, and bile acids

Lipoproteins

transports lipids in blood

Low-Density Lipoprotein (LDL)

Transports cholesterol to body’s tissues; excess leads to plaque build up in arteries → bad cholesterol

High-Density Lipoprotein (HDL)

Carries cholesterol back to liver to make bile acids → good cholesterol

Prototypes of Statin Agents

Lovastatin (Mevaor), Simvastatin (Zocor), Fluvastatin (Lescol)

MOA of Lovastatin (Mevaor), Simvastatin (Zocor), Fluvastatin (Lescol)

Inhibits precursor of cholesterol (HMG-CoA reductase inhibitors) → reducing cholesterol

Adverse Effects of Lovastatin (Mevaor), Simvastatin (Zocor), Fluvastatin (Lescol)

Diarrhea, constipation, rhabdomyolysis

Nursing Concerns for Lovastatin (Mevaor), Simvastatin (Zocor), Fluvastatin (Lescol)

• Avoid digoxin (toxicity) and grapefruit (inhibits statin levels)

• Give at nighttime (cholesterol synthesis is peak)

• Monitor liver function and muscle weakness

Prototype of BIle Sequestering Agents

Cholestyramine (Questram)

MOA of Cholestyramine (Questram)

Binds bile acids in intestines (forms insoluble complexes excreted by kidney) → liver uses more cholesterol to make new bile acids → lowers LDL

Adverse Effects of Cholestyramine (Questram)

Bloating, constipation, diarrhea with high-fat meals; steatorrhea (can’t absorb fat → buildup in stool)

Nursing Concerns of Cholestyramine (Questram)

• Can bind and reduce absorption of digoxin and warfarin (take other meds 1h before or 4h after)

• Contraindicated if completely biliary obstruction

• Exercise, water, fiber enriched diet (constipation)

• Fat soluble vitamins (K, A, E)

• Monitor for bruising and bleeding (low vitamin K)

Prototype of Fibric Acid Agents

Gemfibrozil (Lopid)

MOA of Gemfibrozil (Lopid)

Activates lipoprotein lipase which lowers blood triglycerides → reduces cholesterol production and raises HDL (carries cholesterol to liver)

Adverse Effects of Gemfibrozil (Lopid)

Gallstones and impaired liver function (stressed from processing and clearing fats → ↑ liver enzymes)

Nursing Concerns of Gemfibrozil (Lopid)

• Report abdominal cramping

• Low-cholesterol diet

• No breastfeeding

• Monitor blood glucose if diabetic