Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Focus on PHARMACOLOGY ESSENTIALS FOR HEALTH PROFESSIONALS CHAPTER 23 Anticoagulants Hemostasis: Three Events After Injury 1. Vascular spasms: platelets release serotonin, which causes blood vessel to spasm and decrease blood loss until clotting occurs 2. Platelet plug: platelets become sticky and adhere to vessel lining and each other, forming platelet plug, which is invaded by clotting factors Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Hemostasis: Three Events After Injury 3. Coagulation: clot forms through chemical reactions that create netlike structure of fibrin, sealing off opening in injured vessel Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Figure 23-1 Hemostasis begins when a blood vessel is damaged and ends when the fibrin threads trap blood cells, forming a clot that seals the injured vessel. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Figure 23-2 Basic steps of hemostasis. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Mechanism of Action: Hemostasis • Involves 11 plasma proteins (clotting factors) • Most clotting proteins synthesized by liver • Prothrombin activator, prothrombin, thrombin, fibrinogen, fibrin Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Figure 23-3 The steps in the coagulation cascade. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Anticoagulants • Medications that prolong bleeding time • Do not dissolve clots already formed, but may prevent clots from becoming larger • Used to treat MI, venous thrombosis, pulmonary emboli • Primarily used for thrombosis in veins Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 23-1 Anticoagulants Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Heparin: Uses • Works by increasing length of coagulation; inhibits thrombi from forming or growing larger • Treat emboli, thrombi, MI, and to prevent clotting during open-heart surgery, coronary artery bypass graft, and dialysis Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Heparin: Adverse Effects • Hemorrhage in urinary or GI tracts, subdural hematomas, hemorrhagic pancreatitis, hemarthrosis, ecchymosis Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Heparin: Contraindications • Contraindicated in serious and intracranial bleeding, severe liver or kidney disease, malignant hypertension • Interacts with aspirin, NSAIDs, anesthetics, valproic acid, thrombolytics, and other drugs Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Heparin: Patient Information • Teach patients how to administer heparin subcutaneously. • Advise patients to protect themselves from injury (e.g., use electric shaver). • Warn patients to avoid aspirin and other OTC drugs. • Instruct patients to report signs of bleeding. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Heparin in Older Adults • Older adults are more susceptible to effects of anticoagulants. Signs of overdose include epistaxis, blood in stool or urine, excessive bruising, and prolonged bleeding. • Overdose can be treated by slow infusion of 1% protamine sulfate. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Figure 23-4 Mechanism of action of anticoagulants. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini LMWH: Uses • Greater bioavailability and longer action than heparin • More effective in preventing and treating venous thromboembolism • Less bleeding and fewer episodes of heparin-induced thrombocytopenia Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 23-2 Common Low-Molecular-Weight Heparins Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Warfarin (Coumadin): Uses • Interferes with hepatic synthesis of vitamin K-dependent clotting factors (II, VII, IX, X) • Used on inpatient and outpatient basis for long-term anticoagulation Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Warfarin: Adverse Effects • • • • • • Hemorrhage Diarrhea Urticaria Alopecia Skin necrosis Dermatitis Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Warfarin: Contraindications • Contraindicated in active or previous ulceration, hepatic or renal disease, malignant hypertension, bacterial endocarditis, chronic alcoholism, pregnancy • Interacts with hepatic enzyme inhibitors, aspirin, NSAIDs, and thrombolytics Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Warfarin: Patient Information • Instruct patients to report signs of bleeding; chest, abdominal, lumbar, or pelvic pain. • Advise patient to stop drug immediately if signs of hepatitis occur. • Advise female patients to avoid pregnancy with barrier contraceptive and to avoid breastfeeding. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Warfarin Tips for Patients • Advise patients that 5 days prior to dental procedures, warfarin should be stopped. • Supplemental intake of vitamin K can potentiate or inhibit oral anticoagulants. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antiplatelets: Uses • Prevent platelets from binding together • Used to prevent clot formation in arteries, in MI and stroke, and in PCTA • Aspirin: low doses inhibit platelet aggregation and prolong bleeding time • Ticlopidine (Ticlid) and clopidogrel (Plavix) irreversibly inhibit platelet activation Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antiplatelets: Uses • Abciximab (ReoPro), eptifibatide (Integrilin) and tirofiban (Aggrastat) interrupt interaction of fibrinogen with clotting factors Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 23-3 Antiplatelet Agents Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antiplatelets: Adverse Effects • Epigastric pain, heartburn, nausea, diarrhea, major or minor bleeding • Abciximab: cardiac arrhythmias, abnormal thoughts, dizziness Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antiplatelets: Contraindications • Contraindicated in patients with history of peptic ulcer, hypertension, asthma, allergies, nasal polyps • Interact with anticoagulants, thrombolytic agents, dextran, and other drugs Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Antiplatelets: Patient Information • Instruct patients to report nausea, diarrhea, rash, sore throat, or infections; signs of bleeding; signs of hepatitis. • Advise patients to avoid aspirin and antacids. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Garlic as Anticoagulant • Garlic has been shown to decrease platelet aggregation. • Use of garlic with anticoagulants may increase risk of bleeding complications. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Thrombolytics: Uses • Used to prevent or treat excessive bleeding from surgical sites • Facilitate conversion of plasminogen to plasmin, which hydrolyzes fibrin to dissolve blood clots • Also called plasminogen activators Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Table 23-4 Thrombolytics Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Thrombolytics: Adverse Effects • Common: bleeding caused by fibrinogenolysis or fibrinolysis at site of injury • Serious: intracranial bleeding Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Thrombolytics: Contraindications • Contraindicated in active bleeding, pregnancy, lactation, intracranial trauma, vascular disease, and cancer • Interact with anticoagulants, aspirin, and herbs such as feverfew, ginger, and ginkgo Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Thrombolytics: Patient Information • Instruct patients to report signs of bleeding or changes in consciousness. • Advise women to avoid breastfeeding. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini Thrombocytopenia • Platelet deficiency; most common cause of abnormal bleeding • Hemophilia applies to several hereditary bleeding disorders that result from lack of factors needed for clotting. Focus on Pharmacology: Essentials for Health Professionals, Second Edition Jahangir Moini