HESI Topics (Pharmacology). Comprehensive Study Guide. 34 Pages.
Buy and Download >
CLICK ON THE PRODUCT INFORNMATION URL FOR MORE INFORMATION.
1. Coumadin use, precautions, side effects, and labs Oral anticoagulants inhibit hepatic synthesis of vitamin K. Warfarin is used mainly to prevent thromboembolic conditions such as thrombophle bitis, pulmonary embolism, and embolism formation caused by atrial fibrillation, which can lead to stroke (CVA). Oral anticoagulants prolong clotting time and are monitored by the prothrombin time (PT), a laboratory test that measures the time it takes blood to clot in the presence of certain clotting factors. This laboratory test is usually performed immediately before administering the next drug dose until the therapeutic level has been reached. Today, international normalized ratio (INR) is the laboratory test most frequently used to report PT results. Normal INR is 1.3 to 2. Patients on warfarin therapy are maintained at an INR of 2 to 3. The desired INR for patients who have a mechanical heart valve or recurrent systemic embolism is 2.5 to 3.5, but the desired level could be as high as 4.5. Monitoring INR at regular intervals is required for the duration of drug therapy. Drug accumulation can occur and lead to external or internal bleeding, so the nurse must observe for petechiae, ecchymosis, tarry stools, and hematemesis and teach the patient to do the same at home. The antidote for warfarin overdose is Vitamin K, but it takes 24 to 48 hours to be effective. Usually a low dose of oral Vitamin K may be recommended for patients with an INR of 5.5. If excessive Vitamin K is given, it may take warfarin 1 to 2 weeks before it can be effective again. For acute bleeding, fresh frozen plasma is indicated. Contraindications Drug-Lab-Food Interactions Bleeding disorder, peptic ulcer, severe hepatic or renal disease, hemophilia Blood dyscrasias, eclampsia, alcoholism, bleeding, head trauma Caution: diabetes mellitus, leukemia Pharmacodynamics The PT level should be 1.5 to 2 times the reference value to be therapeutic, or INR should be 2.0 to 3.0. Higher INR levels (up to 3.5) are usually required for patients with prosthetic heart valves, cardiac valvular disease, and recurrent emboli. Heparin does not cross the placental barrier, unlike warfarin. Side Effects and Adverse Reactions. Bleeding (hemorrhage) is the major adverse effect of warfarin. Patients should be monitored closely for signs of bleeding (e.g., petechiae, ecchymosis, hematemesis). Anticoagulant Antagonists Bleeding occurs in about 10% of patients taking oral anticoagulants. Vitamin K1 (phytonadione), an antagonist of warfarin, is used for warfarin overdose or uncontrollable bleeding. Usually 1 to 10?mg of vitamin K1 is given at once, and if it fails to control bleeding, then fresh whole blood or fresh-frozen plasma or platelets are generally given. Patient Teaching General • Aspirin should not be taken with warfarin, because aspirin intensifies its action and bleeding is apt to occur. Suggest that patient use acetaminophen. •Teach patient to control external hemorrhage (bleeding) from accidents or injuries by applying firm, direct pressure for at least 5 to 10 minutes with a clean, dry, absorbent material. Question: 1. A patient is being changed from an injectable anticoagulant to an oral anticoagulant. Which anticoagulant does the nurse realize is administered orally? • a.enoxaparin sodium (Lovenox) • b.warfarin (Coumadin) • c.bivalirudin (Angiomax) • d.lepirudin (Refludan) 2. Steroid use, dc procedure Glucocorticoids (Steroids): end in –sone or -lone Glucocorticoids are used to treat respiratory disorders (COPD, etc.), particularly asthma. These drugs have an antiinflammatory action and are indicated if asthma