41. Anticoagulation Flashcards
CA is a 66 year-old male with hypertension, renal disease and degenerative joint disease. In his younger years, CA was a football player and has lived with the pain of a hip injury for many years. He enters the hospital for elective hip replacement surgery. His creatinine clearance is 25 mL/min. The physician orders enoxaparin 30 mg SC BID for DVT prophylaxis. Choose the correct statement:
A. The dose is correct as ordered.
B. The dose should be 60 mg SC daily.
C. The dose should be 45 mg SC daily.
D. The dose should be 30 mg SC daily.
E. The patient should receive heparin for DVT prophylaxis.
D. The physician ordered the correct prophylactic dose of enoxaparin for a patient without significant renal disease (30 mg SC BID, or 40 mg SC daily). If the creatinine clearance is less than 30 mL/min, the dose is reduced to 30 mg SC once daily.
enoxaparin (Lovenox): use actual body weight for all. Px VTE (30mg SQ Q12H or 40mg SQdaily; CrCl <30, 30mgSQdaily)
Tx VTE and UA/NSTEMI: 1mg/kg SQ Q12H (or 1.5 mg/kg SC Qdaily for VTE inpatient treatment only; CrCl <30, 1mg/kg SQ daily)
Tx STEMI: For patients <75 y/o, 30mg IV bolus + 1mg/kg SQ dose, then 1 mg/kg SQ Q12H (max 100mg for first 2 doses only); if CrCl <30, 30mg IV bolus + 1mg/kg SQ dose, then 1mg/kg SQ daily. For patients ≥75 y/o, 0.75 mg/kg SQ Q12H (no bolus and max 75mg for first 2 doses only); if CrCl <30, give 1mg/kg SQ daily. For PCI: give 0.3mg/kg IV bolus if last dose was 8-12 hours before balloon inflation.
Select the correct statement concerning Pradaxa:
A. It is indicated for patients with valvular atrial fibrillation to reduce the risk of stroke.
B. It has more drug and food interactions than warfarin.
C. It causes the same amount of GI bleeding as warfarin.
D. It has an antidote.
E. It does not require blood testing to monitor for effectiveness.
E. Pradaxa is indicated for non-valvular atrial fibrillation and it does not require blood tests to monitor for effectiveness.Pradaxa causes more GI bleeds and does not have an antidote.
Oral Direct Thrombin (IIa) Inhibitors: directly inhibits thrombin (Factor IIa).
dabigatran (Pradaxa): Prevents more stroke than warfarin and favored in CHEST guidelines. Boxed warning: patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis, premature discontinuation increases risk of thrombotic events. CI: major active bleeding, patients with mechanical heart valves. SE: dyspepsia, gastritis-like symptoms, bleeding (including more GI bleeding), pregnancy (C). No antidote. Take whole capsule with full glass of water without regards to food. Once open bottle, use within 4 months.
Non-valvular AFib: 150mg BID; 75mg BID if CrCl 15-30
Tx of VTE and reduction in risk of recurrence of VTE: 150mg BID when CrCl >30; no recommendations when CrCl <30
Switching from warfarin to dabigatran: start when INR <2
Swithcing from UFH/LMWH: start at end of UFH infusion or within 2 hours of next LMWH dose
Missed dose: take dose if >6 hours from next dose
A 70 year-old patient has been using warfarin therapy in the hospital. She had a deep vein thrombosis (DVT) in her right lower leg. She is being discharged, and the outpatient pharmacist who is going to dispense her warfarin is checking her medication profile for drug interactions. The pharmacist notes that the patient is using medications which increase the risk of bleeding. She will counsel the patient on increased bleeding risk. Which of the following medications can increase her bleeding risk? (Select ALL that apply.)
A. Co-enzyme Q10
B. Clopidogrel
C. Amiodarone
D. Ginkgo biloba
E. Lithium
B, C, D. Clopidogrel, amiodarone, and ginkgo biloba can increase the risk of bleeding in patients taking warfarin.
Herbal/Natural Product Drug: Increase bleeding risk (ginkgo biloba, bromelain, danshen, dong quai, vitamin E, evening primrose oil, echinacea, high doses of fish oils, garlic, glucosamine, goldenseal, grapefruit, policosanol, willow bark, wintergreen oil). Decrease effectiveness of warfarin (alfalfa, American ginseng, green tea, coenzyme Q-10, vitamin K, St John’s Wort) “Alcohol Can Get Gina Singing” = alfalfa, coenzyme, green tea, ginseng, st. john’s.
Chief Complaint: “I can’t walk - it hurts so bad”
History of Present Illness: ST is a 72 y/o female who presents to the ER with left lower extremity swelling that started last week. Her leg became more swollen and painful over the past few days until she could no longer apply weight to her left leg. She reports no shortness of breath or decreased exercise tolerance.
Allergies: NKDA
Past Medical History: Hypertension, Type 2 Diabetes, and Heart Failure
Medications: Lantus 24 units at HS, Novolog 3 units TID before meals, Diovan HCT 160 mg/25 mg daily, Coreg CR 20 mg daily, Neurontin 600 mg TID, Lasix 20 mg daily
Physical Exam / Vitals:
Height: 5’4” Weight: 200 lbs
Vitals: BP: 167/92 HR: 92 RR: 16 Temp: 98.8 F O2 sat: 98% Pain: 8/10
General: Obese female with painful left lower extremity. Appears stated age.
Cardiovascular: RRR
Lungs: CTA bilaterally
Extremities: Left calf circumference > right. Swollen from ankle to knee on left. No swelling on right. Warm to touch, no lesions or infection.
Labs:
Na (mEq/L) = 142 (135 – 145) WBC (cells/mm3) = 5.7 (4 – 11 x 10^3)
K (mEq/L) = 3.7 (3.5 – 5) Hgb (g/dL) = 13.9 (13.5 – 18 male, 12 – 16 female)
Cl (mEq/L) = 99 (95 – 103) Hct (%) = 42 (38 – 50 male, 36 – 46 female)
HCO3 (mEq/L) = 27 (24 – 30) Plt (cells/mm3) = 322 (150 – 450 x 10^3)
BUN (mg/dL) = 31 (7 – 20) AST (IU/L) = 29 (10 – 40)
SCr (mg/dL) = 1.2 (0.6 – 1.3) ALT (IU/L) = 34 (10 – 40)
Glucose (mg/dL) = 202 (100 – 125) Albumin (g/dL) = 4.2 (3.5 – 5)
Ca (mg/dL) = 9.7 (8.5 – 10.5) A1C (%) = 10.1
Mg (mEq/L) = 1.7 (1.3 – 2.1) PT (sec) = 13 (10 - 13)
PO4 (mg/dL) = 2.8 (2.3 – 4.7) INR = 0.8
Tests:
Ultrasound of left lower extremity: DVT
EKG: NSR, no ST or T wave changes
Plan: Admit to medical floor for treatment of DVT and management of other chronic conditions.
Question:
The physician plans to start ST on enoxaparin, but would like to order a laboratory test to monitor efficacy of enoxaparin therapy. Which of the following could be recommended?
A. aPTT Q6H
B. INR daily
C. Peak anti-Xa, 4 hours after the dose
D. Trough anti-Xa, before the next dose
E. There is no laboratory test to monitor efficacy of enoxaparin therapy
C. Routine monitoring of enoxaparin therapy with anti-Xa levels is not necessary, but monitoring can be done in certain patients. If anti-Xa levels are ordered, they should be drawn 4 hours after the SC dose (peak).
Low Molecular Weight Heparin (LMWHs): works similar to heparin except that the inhibition is much greater for Factor Xa than Factor IIa. Boxed warning: patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis. CI: history of HIT, active major bleed, hypersensitivity to pork. SE: bleeding, anemia, increase LFTs, thrombocytopenia, hyperkalemia, injection site reactions (bruising), pregnancy (B). Monitoring (Anti-Xa levels can be used to monitor, but not routine (obtain peak anti-Xa levels 4 hours post dose). Monitor in pregnancy, mechanical valves, morbidly obese, and renal impairment. No real antidote, but protamine can be used. Do not expel air bubble.
What would be expected to occur if a patient on warfarin with a stable INR is started on amiodarone?
A. The INR would decrease and the patient may experience bleeding.
B. The INR would increase and the patient may clot.
C. The INR would increase and the patient may experience bleeding.
D. The INR would decrease and the patient may clot.
E. The INR would not change.
C. Amiodarone inhibits the metabolism of warfarin; therefore, increasing the INR and potentially causing the patient to bleed.
Warfarin is a substrate of CYP 2C9. Avoid use with tamoxifen. 2C9 inducers: aprepitant, bosentan, carbamazepine, phenobarbital, phenytoin, primidone, rifampin (large decrease in INR), licorice, St. John’s Wort. 2C9 inhibitors: amiodarone (decrease warfarin dose by 30-50%), azole antifungals (fluconazole, ketoconazole, voriconazole), capecitabine, etravirine, fluvastatin, fluvoxamine, macrolide antibiotics, metronidazole, tigecycline, TMP/SMX, zafirlukast
The pharmacist is counseling AT, a patient beginning warfarin therapy, on how to recognize if she may be bleeding internally or externally. Signs that she may be bleeding include the following: (Select ALL that apply.)
A. Xerostomia
B. Red or black stools
C. Epistaxis
D. Metallic taste in mouth when she brushes her teeth
E. Headaches, dizziness or weakness
B, C, D, E. Other signs of bleeding could include pain, swelling, or discomfort, bleeding from cuts that takes a long time to stop (usually more than 15 minutes), large bruises, menstrual bleeding or vaginal bleeding that is much heavier than normal, pink or brown urine (or dark, tarry stools) or vomiting blood or material that looks like coffee grounds. Dark tarry stools are more likely with NSAID-induced bleeding, but would be aggravated by an elevated INR.
Which of the following medical conditions put a patient at risk for development of a DVT?
A. Hypertension
B. Type 1 diabetes
C. Urinary tract infection
D. Influenza
E. Cancer
E. Cancer or chemotherapy is a known risk factor for development of DVT.
Risk factors: Major (surgery, major trauma, immobility, cancer, previous venous thromboembolism, pregnancy, estrogen-containing medications or selective estrogen-receptor modulators, erythropoiesis-stimulating agents), other (venous compression, increasing age, acute medical illness, inflammatory bowel disease, nephrotic syndrome, myeloproliferative disorders, paroxysmal nocturnal hemoglobinuria, obesity, central venous catherization, inherited/acquired thrombophilia)
TL was admitted to the local hospital for a knee replacement. Orthopedic surgery is considered high risk for venous thromboembolism (VTE) but TL did not receive any VTE prophylaxis. He developed a deep vein thrombosis and was discharged on warfarin. This was his first incidence of VTE. Normally, TL is thin and active. How long should he receive warfarin?
A. One month
B. Two months
C. Three months
D. Six months
E. Twelve months
C. This patient had an increased risk for VTE only due to the orthopedic surgery. He will need anticoagulation for three months.
VTE treatment
Provoked: treat for 3 months
Unprovoked: low-to-moderate risk (treat longer than 3 months), high bleeding risk (treat for 3 months)
2 unprovoked VTEs: treat long-term
In which of the following scenarios are the intravenous direct thrombin inhibitors considered the drugs of choice?
A. To provide anticoagulation in patients who have heparin-induced thrombocytopenia (HIT).
B. To provide anticoagulation in patients who had a recent intracranial hemorrhage.
C. To provide anticoagulation in patients who had heparin-induced hyperkalemia.
D. To provide better anticoagulation in ACS patients.
E. For patients who are allergic to latex.
A. Direct thrombin inhibitors have been very important clinically since they do not cross-react with heparin-induced thrombocytopenia (HIT) antibodies. Once HIT develops, the injectable direct thrombin inhibitors are the drugs of choice.
IV Direct Thrombin (IIa) Inhibitors: directly inhibit thrombin (Factor IIa). used in patients with a history of HIT. CI: active major bleed. SE: bleeding, anemia, hematoma, pregnancy (B). No cross reaction with HIT. Not antidote.
argatroban: drug of choice in HIT. must be protected from light during administration. decrease dose in hepatic impairment
bivalirudin (Angiomax): used in cardiac cath lab. decrease dose when CrCl <30
Both agents: HIT dosing (initial 2mcg/kg/min, titrate to target aPTT, max 10mcg/kg/min). PCI (IV bolus followed by infusion, all are weight-based)
AT is beginning warfarin therapy. She asks the pharmacist which foods are high in vitamin K. Which of the following foods are high in vitamin K? (Select ALL that apply.)
A. Cauliflower
B. Canola and soybean oils
C. Broccoli and brussels sprouts
D. Fish and fish oils
E. Green and black tea
A, B, C, E. It is important to counsel the patient to eat consistent amounts of vitamin K daily and avoid large, sudden changes in items rich in vitamin K.
A female patient who is pregnant has been admitted to the hospital with a DVT. The physician will begin heparin therapy. What is the mechanism of action of heparin?
A. Heparin potentiates factor V
B. Heparin potentiates factor IXa
C. Heparin potentiates factor Xa
D. Heparin potentiates antithrombin
E. Heparin inhibits clotting factors II, VII, IX, & X
D. Heparin exerts its effects via antithrombin.
Unfractionated Heparin (UFH): binds to antithrombin (AT) and inactivates thrombin (Factor IIa) and Factor Xa (as well as factors IXa, XIa, XIIa, and plasmin) and prevents the conversion of fibrinogen to fibrin.
Px VTE: 5000 units SQ Q8-12H
Tx VTE: 80 units/kg IV bolus (max 5000 units) followed by 18 units/kg/hr (max 1000 units/hr) infusion (actual body weight)
Tx ACS/STEMI: 60 units/kg IV bolus (max 4000 units) followed by 12 units/kg/hr (max 1000 units/hr) infusion (actual body weight)
Boxed warning: some products contain benzyl alcohol as preservative, use is CI in neonates and infants. CI: uncontrolled active bleed, severe thrombocytopenia, ICH, history of HIT, hypersensitivity to pork products. Warning: do not give IM due to hematoma risk. SE: bleeding, thrombocytopenia, heparin induced thrombocytopenia, hyperkalemia, osteoporosis, pregnancy (C). Monitoring: heparin is monitored via the aPTT (6 hours after initiation, then every 6 hours until therapeutic range of 1.5-2.5 x patient’s baseline aPTT), platelet count, Hgb, Hct, bleeding, thrombocytopenia. Antidote: protamine (1mg will reverse 100units of heparin, max dose 50mg)
A patient has developed a DVT and will be placed on dalteparin. Choose the correct statements concerning dalteparin:
A. Dalteparin is safe to use if a person has a history of heparin-induced thrombocytopenia.
B. Dalteparin is safe to use in a patient receiving concurrent neuraxial anesthesia.
C. Dalteparin is administered by intramuscular injection.
D. Dalteparin is monitored by anti-Xa levels but monitoring is not required in everyone.
E. Dalteparin cannot be used safely in a patient with a sulfa allergy.
D. Dalteparin is administered by subcutaneous (SC) injection and is contraindicated if the patient had a history of HIT.
dalteparin (Fragmin): use actual body weight for all. Px VTE: 2500-5000 units SQ daily. Tx UA/NSTEMI: 120 units/kg (max 10000 units) Q12H
Which of the following is the most likely adverse effect from the use of heparin?
A. Leukopenia
B. Hypercalcemia
C. Bleeding
D. Decreased cognitive function
E. Lupus like syndrome
C. The major side effect of heparin is bleeding.
Unfractionated Heparin (UFH): binds to antithrombin (AT) and inactivates thrombin (Factor IIa) and Factor Xa (as well as factors IXa, XIa, XIIa, and plasmin) and prevents the conversion of fibrinogen to fibrin.
Px VTE: 5000 units SQ Q8-12H
Tx VTE: 80 units/kg IV bolus (max 5000 units) followed by 18 units/kg/hr (max 1000 units/hr) infusion (actual body weight)
Tx ACS/STEMI: 60 units/kg IV bolus (max 4000 units) followed by 12 units/kg/hr (max 1000 units/hr) infusion (actual body weight)
Boxed warning: some products contain benzyl alcohol as preservative, use is CI in neonates and infants. CI: uncontrolled active bleed, severe thrombocytopenia, ICH, history of HIT, hypersensitivity to pork products. Warning: do not give IM due to hematoma risk. SE: bleeding, thrombocytopenia, heparin induced thrombocytopenia, hyperkalemia, osteoporosis, pregnancy (C). Monitoring: heparin is monitored via the aPTT (6 hours after initiation, then every 6 hours until therapeutic range of 1.5-2.5 x patient’s baseline aPTT), platelet count, Hgb, Hct, bleeding, thrombocytopenia. Antidote: protamine (1mg will reverse 100units of heparin, max dose 50mg)
A 42 year-old female with a heart condition is presenting to the hospital with a DVT. The medical resident wishes to give her a low molecular weight heparin (LMWH), but the older supervising physician insists on using heparin. What are advantages to the use of LMWHs over heparin? (Select ALL that apply.)
A. LMWHs are more efficacious than heparin in treating DVTs.
B. LMWHs are more cost effective than heparin.
C. LMWHs are easier to reverse in patients that experience significant bleeding.
D. LMWHs do not require monitoring in some patients.
E. LMWHs have a more consistent anticoagulation response.
B, D, E. Unlike heparin, LMWHs do not require monitoring in every patient. Anti-factor Xa levels can be monitored in select patients, but this is not necessary in most patients. LMWHs are more cost-effective than heparin.
Which of the following procedures can help reduce medication errors associated with heparin? (Select ALL that apply.)
A. Do not use the color of the syringe or packaging to verify the dose.
B. Provide inservices that review heparin safety, including the lower heparin flush concentrations to the higher treatment doses.
C. If possible, outsource the preparation of heparin flushes.
D. Make sure unit nurses prepare the heparin doses.
E. Have the pharmacist verify the heparin concentration for the patient’s indication.
A, B, C, E. Heparin as an anticoagulant comes in different strengths. To help avoid errors, heparin should not be stocked in unfamiliar concentrations. The concentration must be verified by the pharmacist prior to dispensing the dose. The color of the bag or syringe should not be used to verify the dose. Having the pharmacy prepare the flush syringes (rather than busy unit nurses) can help reduce errors. Buying prepared heparin syringes (outsourcing) is most preferable.
The pharmacist will counsel a patient on the correct self-administration technique for enoxaparin. Which of the following are correct counseling statements? (Select ALL that apply.)
A. This medication can cause you to bruise and/or bleed more easily.
B. Choose an area on the right or left side of your abdomen, but not within two inches from the belly button.
C. Do not expel the air bubble in the syringe prior to injection.
D. Store this medication in the refrigerator until just prior to each use.
E. It is best to rub the injection site after administration to ensure quick absorption.
A, B, C. Do not expel the air bubble in the syringe as it can cause the patient to get a subtherapeutic dose because some of the medicine will be lost (as long as the exact dose needed is the amount in the syringe). With some medications it is recommended to rub the site after injection, but not with drugs that can cause bleeding, such as this one.
Select the correct indication for dabigatran:
A. To provide anticoagulation in patients with acute coronary syndrome.
B. To reduce the risk of stroke and blood clots in patients with non-valvular atrial fibrillation.
C. To reduce the risk of stroke and blood clots in patients with ventricular tachycardia.
D. To provide anticoagulation in patients who had bleeding on heparin.
E. To reduce the risk of a secondary stroke in patients who have a subarachnoid hemorrhage.
B. Dabigatran is indicated to reduce the risk of stroke and systemic embolism in patients with non-valvular atrial fibrillation, to treat DVT/PE, and to reduce risk of recurrence of DVT/PE.
Oral Direct Thrombin (IIa) Inhibitors: directly inhibits thrombin (Factor IIa).
dabigatran (Pradaxa): Prevents more stroke than warfarin and favored in CHEST guidelines. Boxed warning: patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis, premature discontinuation increases risk of thrombotic events. CI: major active bleeding, patients with mechanical heart valves. SE: dyspepsia, gastritis-like symptoms, bleeding (including more GI bleeding), pregnancy (C). No antidote. Take whole capsule with full glass of water without regards to food. Once open bottle, use within 4 months.
Non-valvular AFib: 150mg BID; 75mg BID if CrCl 15-30
Tx of VTE and reduction in risk of recurrence of VTE: 150mg BID when CrCl >30; no recommendations when CrCl <30
Switching from warfarin to dabigatran: start when INR <2
Swithcing from UFH/LMWH: start at end of UFH infusion or within 2 hours of next LMWH dose
Missed dose: take dose if >6 hours from next dose
HY is a 58 year-old male with atrial fibrillation. He has been using warfarin for over two years and is normally well-controlled. His cardiologist recently began amiodarone and citalopram therapy with no other medication adjustments. He is admitted to the emergency room with weakness and bleeding gums. The INR is obtained and is 9.5. His hemoglobin is 8.4 g/dL. His pants are stained with blood which is coming from his rectum. Choose the correct course of action:
A. Hold warfarin x 1 dose and administer phytonadione 1 to 2.5 mg orally.
B. Omit the next 1-2 doses, monitor frequently, and resume therapy when the INR is in the therapeutic range.
C. Hold warfarin and administer phytonadione 2 mg by SC injection.
D. Hold warfarin therapy and give vitamin K 10 mg by slow IV injection along with four-factor prothrombin complex concentrate.
E. Hold warfarin therapy and give vitamin K 10 mg by IM injection and fresh frozen plasma.
D. With major bleeding, vitamin K 10 mg should be given by slow IV injection along with four-factor prothrombin complex concentrate, which is preferred over fresh frozen plasma.
Treating Supratherapeutic INRs:
Antidote is vitamin K: PO or IV only.
INR above range, but <4.5 = reduce or skip dose of warfarin. resume when therapeutic (may need to reduce dose)
INR of 4.5-10, without bleeding = PO vitamin K only if high bleeding risk 1-2.5mg. resume warfarin at lower dose
INR >10, without bleeding = PO vitamin K 2.5-5mg. hold warfarin
Major bleeding from warfarin (any INR) = IV vitamin K 5-10mg AND four factor prothrombin complex concentrate (PCC) due to less risks. hold warfarin therapy
HM is receiving a heparin drip. What is the name of the test used to monitor heparin for efficacy?
A. Potentiation factor
B. Factors IIa, VIIa, IXa and Xa test
C. Anti-XIa levels
D. International normalized ratio
E. The activated partial thromboplastin time
E. The activated partial thromboplastin time (aPTT) is used to monitor the effect of heparin. The aPTT is the time, in seconds, for plasma to clot. A normal aPTT is generally between 22-38 seconds. The therapeutic aPTT range is determined individually for each hospital or laboratory depending on the reagent.
Unfractionated Heparin (UFH): binds to antithrombin (AT) and inactivates thrombin (Factor IIa) and Factor Xa (as well as factors IXa, XIa, XIIa, and plasmin) and prevents the conversion of fibrinogen to fibrin.
Px VTE: 5000 units SQ Q8-12H
Tx VTE: 80 units/kg IV bolus (max 5000 units) followed by 18 units/kg/hr (max 1000 units/hr) infusion (actual body weight)
Tx ACS/STEMI: 60 units/kg IV bolus (max 4000 units) followed by 12 units/kg/hr (max 1000 units/hr) infusion (actual body weight)
Boxed warning: some products contain benzyl alcohol as preservative, use is CI in neonates and infants. CI: uncontrolled active bleed, severe thrombocytopenia, ICH, history of HIT, hypersensitivity to pork products. Warning: do not give IM due to hematoma risk. SE: bleeding, thrombocytopenia, heparin induced thrombocytopenia, hyperkalemia, osteoporosis, pregnancy (C). Monitoring: heparin is monitored via the aPTT (6 hours after initiation, then every 6 hours until therapeutic range of 1.5-2.5 x patient’s baseline aPTT), platelet count, Hgb, Hct, bleeding, thrombocytopenia. Antidote: protamine (1mg will reverse 100units of heparin, max dose 50mg)
Low molecular weight heparins have a boxed warning concerning this risk:
A. Stevens Johnson syndrome
B. Spinal or epidural hematoma formation
C. Pancreatitis
D. Severe bleeding
E. Acute renal failure
B. The risk is highest if the patient receives neuraxial anesthesia or has a spinal puncture concurrently. These hematomas may result in long-term or permanent paralysis.
Low Molecular Weight Heparin (LMWHs): works similar to heparin except that the inhibition is much greater for Factor Xa than Factor IIa. Boxed warning: patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis. CI: history of HIT, active major bleed, hypersensitivity to pork. SE: bleeding, anemia, increase LFTs, thrombocytopenia, hyperkalemia, injection site reactions (bruising), pregnancy (B). Monitoring (Anti-Xa levels can be used to monitor, but not routine (obtain peak anti-Xa levels 4 hours post dose). Monitor in pregnancy, mechanical valves, morbidly obese, and renal impairment. No real antidote, but protamine can be used. Do not expel air bubble.
enoxaparin (Lovenox): use actual body weight for all. Px VTE (30mg SQ Q12H or 40mg SQdaily; CrCl <30, 30mgSQdaily)
Tx VTE and UA/NSTEMI: 1mg/kg SQ Q12H (or 1.5 mg/kg SC Qdaily for VTE inpatient treatment only; CrCl <30, 1mg/kg SQ daily)
Tx STEMI: For patients <75 y/o, 30mg IV bolus + 1mg/kg SQ dose, then 1 mg/kg SQ Q12H (max 100mg for first 2 doses only); if CrCl <30, 30mg IV bolus + 1mg/kg SQ dose, then 1mg/kg SQ daily. For patients ≥75 y/o, 0.75 mg/kg SQ Q12H (no bolus and max 75mg for first 2 doses only); if CrCl <30, give 1mg/kg SQ daily. For PCI: give 0.3mg/kg IV bolus if last dose was 8-12 hours before balloon inflation.
dalteparin (Fragmin): use actual body weight for all. Px VTE: 2500-5000 units SQ daily. Tx UA/NSTEMI: 120 units/kg (max 10000 units) Q12H
A 25 year-old female is receiving warfarin for a DVT. Her counseling should include the following:
A. Warfarin is safe in pregnancy (Pregnancy Category A)
B. Warfarin may be safe in pregnancy (Pregnancy Category B)
C. Warfarin may be unsafe in pregnancy (Pregnancy Category C)
D. Warfarin is unsafe in pregnancy but can be used if the benefits outweigh the risks (Pregnancy Category D)
E. Warfarin is unsafe in pregnancy and cannot be used (Pregnancy Category X)
E. Warfarin is contraindicated in pregnancy (Pregnancy Category X) unless the patient has a mechanical heart valve (Pregnancy Category D).
warfarin (Coumadin, Jantoven): competitively inhibits the C1 subunit of the multi-unit vitamin L epoxide reductase (VKORC1) enzyme complex, thereby reducing the regeneration of vitamin K epoxide and causing depletion of active clotting factors II, VII, IX and X and protein C/S. Boxed warning: may cause major or fatal bleeding. CI: hemorrhagic tendencies (cerebrovascular hemorrhage, bacterial endocarditis, pericarditis, pericardial effusions), blood dyscrasias, pregnancy (except with mechanical heart valves at high risk for thromboembolism), uncontrolled hypertension, non-compliance, recent or potential surgery of the eye or CNS, major regional lumbar block anesthesia or traumatic surgery resulting in large, open surfaces, (pre-)eclampsia, threatened abortion. SE: bleeding, skin necrosis, purple toe syndrome, pregnancy (X), pregnancy (D) for mechanical heart valve. Monitor: INR target 2.5, range is 2-3 for most (2.5-3.5 for mechanical mitral valve or 2 mechanical heart valves). Antidote is vitamin K. S-enantiomer is 2.7-3.8 times more potent than R-enantiomer.
A patient is being started on Pradaxa. Choose the correct statement regarding Pradaxa:
A. Once a bottle of Pradaxa is opened, the capsules must be used within 15 days.
B. Once a bottle of Pradaxa is opened, the capsules must be used within 60 days.
C. Once a bottle of Pradaxa is opened, the capsules must be used within 90 days.
D. Once a bottle of Pradaxa is opened, the capsules must be used within 120 days.
E. If Pradaxa capsules are transferred to an amber container, they are good up to 2 months.
D. The 60-count bottles of Pradaxa expire 4 months after opening the bottle.
Oral Direct Thrombin (IIa) Inhibitors: directly inhibits thrombin (Factor IIa).
dabigatran (Pradaxa): Prevents more stroke than warfarin and favored in CHEST guidelines. Boxed warning: patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis, premature discontinuation increases risk of thrombotic events. CI: major active bleeding, patients with mechanical heart valves. SE: dyspepsia, gastritis-like symptoms, bleeding (including more GI bleeding), pregnancy (C). No antidote. Take whole capsule with full glass of water without regards to food. Once open bottle, use within 4 months.
JK is a 62 year-old female with chronic urinary tract infections. Several times a year, she receives a prescription for Bactrim. The physician suggested she use the antibiotic daily, but she prefers not to because she feels that she is already using too many medications. JK comes to the pharmacy today with a prescription for warfarin. She tells the pharmacist that the heart doctor found her heart was “beating funny.” The pharmacist should emphasize the following counseling to JK: (Select ALLthat apply.)
A. If you get a UTI, the antibiotic Bactrim could make your warfarin level increase.
B. When taking the warfarin and Bactrim, separate the doses by 4 hours to decrease the risk of the drug interaction.
C. The drug interaction between warfarin and Bactrim for a UTI may lead to significant bleeding.
D. Warfarin can cause the Bactrim to be ineffective in treating the UTI.
E. Make sure to inform your health care providers that you are using warfarin so they can choose alternative medications that do not cause drug-drug interactions.
A, C, E. Bactrim can inhibit the metabolism of warfarin putting the patient at risk for bleeding. All providers treating JK should know she is taking warfarin to prevent drug-drug interactions.
Warfarin is a substrate of CYP 2C9. Avoid use with tamoxifen. 2C9 inducers: aprepitant, bosentan, carbamazepine, phenobarbital, phenytoin, primidone, rifampin (large decrease in INR), licorice, St. John’s Wort. 2C9 inhibitors: amiodarone (decrease warfarin dose by 30-50%), azole antifungals (fluconazole, ketoconazole, voriconazole), capecitabine, etravirine, fluvastatin, fluvoxamine, macrolide antibiotics, metronidazole, tigecycline, TMP/SMX, zafirlukast
A patient has developed a DVT and will be placed on dalteparin. What is the correct brand name for dalteparin?
A. Apixaban
B. Fragmin
C. Arixtra
D. Pradaxa
E. Angiomax
B. The brand name for dalteparin is Fragmin.
apixaban (Eliquis)
Arixtra (fondaparinux)
Pradaxa (dabigatran)
Angiomax (bivalirudin)
Patients may use the following non-pharmacological method to reduce the risk of venous thromboembolism:
A. Increase their intake of green leafy vegetables.
B. Perform several reps of 10 deep squats daily, if the physician approves this type of exercise.
C. Consume lots of water.
D. Use intermittent pneumatic compression devices.
E. Consume more olive oil and green tea.
E. Graduated compression stockings (GCS) and intermittent pneumatic compression (IPC) devices are two non-pharmacologic measures used to prevent venous thromboembolism.
Chief Complaint: “I can’t walk - it hurts so bad”
History of Present Illness: ST is a 72 y/o female who presents to the ER with left lower extremity swelling that started last week. Her leg became more swollen and painful over the past few days until she could no longer apply weight to her left leg. She reports no shortness of breath or decreased exercise tolerance.
Allergies: NKDA
Past Medical History: Hypertension, Type 2 Diabetes, and Heart Failure
Medications: Lantus 24 units at HS, Novolog 3 units TID before meals, Diovan HCT 160 mg/25 mg daily, Coreg CR 20 mg daily, Neurontin 600 mg TID, Lasix 20 mg daily
Physical Exam / Vitals:
Height: 5’4” Weight: 200 lbs
Vitals: BP: 167/92 HR: 92 RR: 16 Temp: 98.8 F O2 sat: 98% Pain: 8/10
General: Obese female with painful left lower extremity. Appears stated age.
Cardiovascular: RRR
Lungs: CTA bilaterally
Extremities: Left calf circumference > right. Swollen from ankle to knee on left. No swelling on right. Warm to touch, no lesions or infection.
Labs:
Na (mEq/L) = 142 (135 – 145) WBC (cells/mm3) = 5.7 (4 – 11 x 10^3)
K (mEq/L) = 3.7 (3.5 – 5) Hgb (g/dL) = 13.9 (13.5 – 18 male, 12 – 16 female)
Cl (mEq/L) = 99 (95 – 103) Hct (%) = 42 (38 – 50 male, 36 – 46 female)
HCO3 (mEq/L) = 27 (24 – 30) Plt (cells/mm3) = 322 (150 – 450 x 10^3)
BUN (mg/dL) = 31 (7 – 20) AST (IU/L) = 29 (10 – 40)
SCr (mg/dL) = 1.2 (0.6 – 1.3) ALT (IU/L) = 34 (10 – 40)
Glucose (mg/dL) = 202 (100 – 125) Albumin (g/dL) = 4.2 (3.5 – 5)
Ca (mg/dL) = 9.7 (8.5 – 10.5) A1C (%) = 10.1
Mg (mEq/L) = 1.7 (1.3 – 2.1) PT (sec) = 13 (10 - 13)
PO4 (mg/dL) = 2.8 (2.3 – 4.7) INR = 0.8
Tests:
Ultrasound of left lower extremity: DVT
EKG: NSR, no ST or T wave changes
Plan: Admit to medical floor for treatment of DVT and management of other chronic conditions.
Question:
ST’s healthcare provider would like to start warfarin per the Anticoagulation Management protocol at the hospital. Which of the following is appropriate to start along with warfarin on Day #1 of therapy for the DVT?
A. Heparin 5000 units SQ Q8H
B. Xarelto 20 mg daily
C. Eliquis 2.5 mg BID
D. Iprivask 15 mg SC Q12H
E. Lovenox 90 mg SC Q12H
E. Warfarin should be started on the same day as a parenteral anticoagulant (LMWH or UFH) for DVT/PE. The parenteral anticoagulant must be used in a treatment dose, not a prophylactic dose.
Heparin: Tx VTE: 80 units/kg IV bolus (max 5000 units) followed by 18 units/kg/hr (max 1000 units/hr) infusion (actual body weight)
enoxaparin (Lovenox): use actual body weight for all. Px VTE (30mg SQ Q12H or 40mg SQdaily; CrCl <30, 30mgSQdaily)
Tx VTE and UA/NSTEMI: 1mg/kg SQ Q12H (or 1.5 mg/kg SC Qdaily for VTE inpatient treatment only; CrCl <30, 1mg/kg SQ daily)
Why is it important for hospitals to get INRs taken at about the same time in the morning?
A. The INR must be taken before antibiotics are administered that day.
B. The INR value will be inaccurate if taken later in the day due to the effect of meals.
C. Healthcare providers will have the INR value and be able to adjust that day’s warfarin dose.
D. All labs are taken in the morning per most hospital’s policies and procedures.
E. Warfarin, hence the INR, is affected by the diurnal rhythm of the body.
C. Warfarin is generally dosed in the late afternoon or evening. If the INR is taken earlier in the day, the warfarin dose can still be adjusted prior to administration. Or, if the INR is elevated, the warfarin can be held.
A pharmacist working in an inpatient medical ward of the local hospital is responsible for monitoring anticoagulation therapy. She routinely obtains laboratory parameters and adjusts the doses of low molecular weight heparins (LMWHs), as needed. In which of the following clinical situations is it appropriate to monitor the level of anticoagulation with LMWH therapy? (Select ALL that apply.)
A. Patients with a myocardial infarction
B. Significant renal impairment
C. Pregnancy
D. Mechanical heart valves
E. Extremes of body weight
B, C, D, E. All four clinical scenarios are appropriate for monitoring LMWH therapy.
Monitor in pregnancy, mechanical valves, morbidly obese, and renal impairment.
What routes of administration can heparin be given?
A. Intravenous and buccal administration
B. Intravenous and intramuscular administration
C. Intravenous, intramuscular and oral administration
D. Intravenous, intramuscular and subcutaneous administration
E. Intravenous and subcutaneous administration
E. Heparin is administered by IV or SC injection. Heparin is not administered by IM injection due to pain and the risk of hematoma formation. Heparin is not bioavailable via the oral route.
What would be expected to occur if a patient on warfarin with a stable INR is started on phenobarbital? (Select ALL that apply.)
A. The INR would increase.
B. The INR would decrease.
C. The patient may clot.
D. The patient may experience bleeding.
E. The INR would not change.
B, C. Phenobarbital is a strong hepatic enzyme inducer and would lower the INR and put the patient at risk for clotting.
Warfarin is a substrate of CYP 2C9. Avoid use with tamoxifen. 2C9 inducers: aprepitant, bosentan, carbamazepine, phenobarbital, phenytoin, primidone, rifampin (large decrease in INR), licorice, St. John’s Wort. 2C9 inhibitors: amiodarone (decrease warfarin dose by 30-50%), azole antifungals (fluconazole, ketoconazole, voriconazole), capecitabine, etravirine, fluvastatin, fluvoxamine, macrolide antibiotics, metronidazole, tigecycline, TMP/SMX, zafirlukast
Rivaroxaban works by the following mechanism of action:
A. Vitamin K antagonist
B. Factor Xa inhibitor
C. Direct Factor IIa inhibitor
D. PAR-1 inhibitor
E. Inhibits antithombin
B. Rivaroxaban is an oral Factor Xa inhibitor.
Oral Factor Xa Inhibitors (no not use in mechanical heart valve)
rivaroxaban (Xarelto): Boxed warning: patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis, premature discontinuation increases risk of thrombotic events. CI: active major bleeding. Warnings: avoid with moderate-severe hepatic impairment or any degree associated with coagulopathy, avoid use in severe renal impairment (DVT tx/px CrCl <30; AFib CrCl<15). SE: bleeding anemia, pregnancy (C). No antidote. Discontinue 24 hours prior to elective surgery. *Any dose ≥15mg needs to be taken with food*
Non-valvular AFib: CrCl >50 = 20mg PO daily with evening meal, CrCl 15-50 = 15mg PO daily with evening meal, CrCl <15 = avoid use
Tx VTE: 15mg PO BID with food x 21 days, then 20mg PO daily with food. CrCl <30 = avoid use
Px DVT (after hip/knee replacement): 10mg PO daily without regards to meal. CrCl <30 = avoid use
Reduction in risk of recurrence of DVT/PE: 20mg PO daily with food. CrCl <30 = avoid use
Switching from warfarin to rivaroxaban: start when INR <3
Switching from UFH/LMWH: start at end of infusion or within 2 hours of next evening LMWH dose
Missed doses: take as soon as possible on same day. Do not double up EXCEPT when taking 15mg BID (be sure to take 30mg total daily)
Chief Complaint: “I can’t walk - it hurts so bad”
History of Present Illness: ST is a 72 y/o female who presents to the ER with left lower extremity swelling that started last week. Her leg became more swollen and painful over the past few days until she could no longer apply weight to her left leg. She reports no shortness of breath or decreased exercise tolerance.
Allergies: NKDA
Past Medical History: Hypertension, Type 2 Diabetes, and Heart Failure
Medications: Lantus 24 units at HS, Novolog 3 units TID before meals, Diovan HCT 160 mg/25 mg daily, Coreg CR 20 mg daily, Neurontin 600 mg TID, Lasix 20 mg daily
Physical Exam / Vitals:
Height: 5’4” Weight: 200 lbs
Vitals: BP: 167/92 HR: 92 RR: 16 Temp: 98.8 F O2 sat: 98% Pain: 8/10
General: Obese female with painful left lower extremity. Appears stated age.
Cardiovascular: RRR
Lungs: CTA bilaterally
Extremities: Left calf circumference > right. Swollen from ankle to knee on left. No swelling on right. Warm to touch, no lesions or infection.
Labs:
Na (mEq/L) = 142 (135 – 145) WBC (cells/mm3) = 5.7 (4 – 11 x 10^3)
K (mEq/L) = 3.7 (3.5 – 5) Hgb (g/dL) = 13.9 (13.5 – 18 male, 12 – 16 female)
Cl (mEq/L) = 99 (95 – 103) Hct (%) = 42 (38 – 50 male, 36 – 46 female)
HCO3 (mEq/L) = 27 (24 – 30) Plt (cells/mm3) = 322 (150 – 450 x 10^3)
BUN (mg/dL) = 31 (7 – 20) AST (IU/L) = 29 (10 – 40)
SCr (mg/dL) = 1.2 (0.6 – 1.3) ALT (IU/L) = 34 (10 – 40)
Glucose (mg/dL) = 202 (100 – 125) Albumin (g/dL) = 4.2 (3.5 – 5)
Ca (mg/dL) = 9.7 (8.5 – 10.5) A1C (%) = 10.1
Mg (mEq/L) = 1.7 (1.3 – 2.1) PT (sec) = 13 (10 - 13)
PO4 (mg/dL) = 2.8 (2.3 – 4.7) INR = 0.8
Tests:
Ultrasound of left lower extremity: DVT
EKG: NSR, no ST or T wave changes
Plan: Admit to medical floor for treatment of DVT and management of other chronic conditions.
Question:
On Day #6 of the hospitalization, ST is doing better. Her chronic conditions are under better control. ST mentions to the case manager that she lives almost 2 hours from town and has no transportation to come to the clinic for labs or office visits. The physician would like to discharge ST on an oral anticoagulant that does not require laboratory monitoring. Which of the following are options for ST? (Select ALL that apply.)
A. Lovenox
B. Pradaxa
C. Arixtra
D. Xarelto
E. Eliquis
B, D, E. Pradaxa, Xarelto and Eliquis are oral anticoagulant options for this patient that do not require laboratory monitoring for efficacy.
Vitamin K given IV has a risk of the following adverse reaction:
A. Acute dystrophy
B. Seizures
C. Peripheral neuropathy
D. Anaphylaxis
E. Neuroleptic malignant syndrome
D. The administration of vitamin K intravenously is associated with the risk of anaphylaxis (dyspnea, cardiac arrest, hypotension, shock).
JW arrives at the clinic pharmacy with a prescription for apixaban 5 mg BID. He is 52 years old, 6’1” and weighs 214 lbs. His recent laboratory parameters include a Na+ 139 mEq/L and SCr of 1.1 mg/dL. At the clinic today, he was diagnosed with a DVT. Which of the following statements are correct regarding apixaban for this patient?
A. This is the correct dose for treatment of a DVT or PE.
B. Apixaban must be taken with food.
C. Apixaban is not approved for treating DVT.
D. Apixaban is indicated for stroke prevention in patients with prosthetic heart valves.
E. Apixaban carries a boxed warning regarding the risk of stroke in patients who discontinue therapy prematurely.
E. Apixaban dosing differs for each indication. It can be taken without regards to food. Discontinuation of therapy without adequate anticoagulation with an alternative agent increases the risk of stroke.
apixaban (Eliquis): Boxed warning: patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis, premature discontinuation increases risk of thrombotic events. CI: active major bleeding. Warning: use not recommended with prosthetic heart valves or severe hepatic impairment. SE: bleeding, anemia, pregnancy (B). No antidote. Discontinue 48 hours prior to elective surgery with moderate/high bleeding risk or 24 hours prior if low bleeding risk.
Non-valvular AFib: 5mg BID, or 2.5mg BID if they have at least 2 of the following: age ≥80 y/o, body weight ≤60kg, or SCr ≥1.5
Tx of VTE: 10mg PO BID x 7 days, then 5mg PO BID
Px DVT (after hip/knee replacement): 2.5mg PO BID
Reduction in risk of recurrence of DVT/PE: 2.5mg PO BID
Switching from warfarin to apixaban: start when INR <2
Switching from apixaban to anticoagulants other than warfarin: discontinue apixaban and start other anticoagulant at next scheduled dose.
Missed dose: take as soon as possible on same day; do not double up
Which of the following should be discussed with a patient receiving a new prescription for Pradaxa?
A. The generic name of this medication is rivaroxaban.
B. This medication must be kept in the original container. Do not put into a pill box.
C. This medication requires periodic laboratory monitoring.
D. This medication is used to prevent blood clots around your artificial heart valve.
E. Take this medication with food.
B. Dabigatran (Pradaxa) must be kept in the original container and discarded 4 months after opening the original container. Capsules must be swallowed whole.
Oral Direct Thrombin (IIa) Inhibitors: directly inhibits thrombin (Factor IIa).
dabigatran (Pradaxa): Prevents more stroke than warfarin and favored in CHEST guidelines. Boxed warning: patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis, premature discontinuation increases risk of thrombotic events. CI: major active bleeding, patients with mechanical heart valves. SE: dyspepsia, gastritis-like symptoms, bleeding (including more GI bleeding), pregnancy (C). No antidote. Take whole capsule with full glass of water without regards to food. Once open bottle, use within 4 months.
Non-valvular AFib: 150mg BID; 75mg BID if CrCl 15-30
Tx of VTE and reduction in risk of recurrence of VTE: 150mg BID when CrCl >30; no recommendations when CrCl <30
Switching from warfarin to dabigatran: start when INR <2
Swithcing from UFH/LMWH: start at end of UFH infusion or within 2 hours of next LMWH dose
Missed dose: take dose if >6 hours from next dose
The anticoagulation service routinely performs an audit of the charts for patients who were treated with warfarin and enoxaparin to verify that enoxaparin was bridged and discontinued correctly. BH is a 56 year old male patient who was admitted for a DVT. His laboratory and medication administration history are included below:
Day INR Medications
1 0.8 Warfarin and enoxaparin 110 mg SC Q12H
2 1.3 Warfarin and enoxaparin 110 mg SC Q12H
3 1.7 Warfarin and enoxaparin 110 mg SC Q12H
4 2.1 Warfarin and enoxaparin 110 mg SC Q12H
5 2.4 Warfarin and enoxaparin 110 mg SC Q12H
6 2.6 Warfarin and enoxaparin 110 mg SC Q12H
7 2.5 Discharge
On which day of BH’s hospitalization should enoxaparin have been discontinued?
A. Day 3
B. Day 4
C. Day 5
D. Day 6
E. Day 7
C. Both anticoagulants should be continued for a minimum of 5 days and until the INR is ≥ 2 for at least 24 hours. This is a common arena for quality improvement and cost saving in hospitals. Continuing the parenteral anticoagulant longer than needed increases cost, length of stay, and potential for adverse effects.
Which of the following is a possible side effect from the long-term use of heparin therapy?
A. Gingival hyperplasia
B. Osteoporosis
C. GERD
D. Hair growth
E. Hypokalemia
B. Osteoporosis can occur with long-term use. Women who are pregnant and are using heparin long-term are at risk for decreased bone density.
Boxed warning: some products contain benzyl alcohol as preservative, use is CI in neonates and infants. CI: uncontrolled active bleed, severe thrombocytopenia, ICH, history of HIT, hypersensitivity to pork products. Warning: do not give IM due to hematoma risk. SE: bleeding, thrombocytopenia, heparin induced thrombocytopenia, hyperkalemia, osteoporosis, pregnancy (C). Monitoring: heparin is monitored via the aPTT (6 hours after initiation, then every 6 hours until therapeutic range of 1.5-2.5 x patient’s baseline aPTT), platelet count, Hgb, Hct, bleeding, thrombocytopenia. Antidote: protamine (1mg will reverse 100units of heparin, max dose 50mg)
A hospitalized patient developed a pulmonary embolism and was started on enoxaparin therapy. The physician began warfarin therapy on Monday and wrote an order to discontinue the enoxaparin therapy the following day. The pharmacist contacted the prescriber to recommend the following action:
A. Continue the enoxaparin until the INR reaches the therapeutic range for one value.
B. Continue the enoxaparin until the INR has been therapeutic for at least 24 hours.
C. Continue the enoxaparin until the INR has been therapeutic for at least 48 hours.
D. Continue the enoxaparin for a full 7 days and the patient has been therapeutic for at least 2 of those days.
E. Pulmonary emboli cannot be treated with warfarin; the warfarin should be discontinued.
B. Continuation of the parenteral anticoagulant should occur for a minimum of 5 days and until the INR is therapeutic (INR at 2.0 or above in this scenario) for at least 24 hours.
Which of the following groups of laboratory parameters need to be monitored during heparin therapy?
A. Hematocrit, hemogloblin, platelets, and PT
B. Hematocrit, hemoglobin, platelets, AST, and ALT
C. SCr, platelets, aPTT, and PT
D. Hematocrit, hemoglobin, platelets, and aPTT
E. Platelets, aPTT, PT, and SCr
D. Hematocrit, hemoglobin, platelets, and aPTT are important laboratory parameters to monitor while a patient is receiving heparin therapy.
What is the purpose of using a heparin “lock-flush,” such as HepFlush?
A. To provide systemic anticoagulation prophylaxis
B. To provide systemic anticoagulation treatment
C. To keep IV lines open
D. To prevent HIT
E. To dilute other medications going through the same IV line
C. Heparin “lock-flushes” (HepFlush) are used to keep IV lines open (patent). They are not used for anticoagulation. There have been fatal errors made by choosing the incorrect heparin strength. Using a higher dose to flush a line could cause significant bleeding, including fatal hemorrhage. Many of the dosing errors have occurred in neonates.
Select the correct mechanism of action for Lovenox:
A. Oral direct thrombin inhibitor
B. Injectable direct thrombin inhibitor
C. Vitamin K antagonist
D. Inhibits Factor Xa and Factor IIa via antithrombin
E. Selectively inhibits Factor Xa
D. Lovenox is a low molecular weight heparin (LMWH). LMWHs work by binding to antithrombin which then inhibit clotting factors Xa and IIa.
Low Molecular Weight Heparin (LMWHs): works similar to heparin except that the inhibition is much greater for Factor Xa than Factor IIa. Boxed warning: patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis. CI: history of HIT, active major bleed, hypersensitivity to pork. SE: bleeding, anemia, increase LFTs, thrombocytopenia, hyperkalemia, injection site reactions (bruising), pregnancy (B). Monitoring (Anti-Xa levels can be used to monitor, but not routine (obtain peak anti-Xa levels 4 hours post dose). Monitor in pregnancy, mechanical valves, morbidly obese, and renal impairment. No real antidote, but protamine can be used. Do not expel air bubble.
When heparin is administered, the following laboratory value must be carefully monitored:
A. White blood cells
B. Eosinophils
C. Platelets
D. Amylase
E. Sodium
C. A serious adverse effect associated with heparin therapy is heparin-induced thrombocytopenia, or HIT. This is a significant drop in platelets caused by an immune response against platelets. Platelets must be monitored during therapy.
Heparin-induced Thrombocytopenia (HIT)
IgG mediated drug reaction that forms heparin antibodies which binds to platelet factor 4 (PF4) and heparin PF4/heparin complex. This complex binds to Fc receptors on platelets and activates platelets. HIT is defined as a platelet drop of >50% from baseline, putting patients into a prothrombotic state which could lead to HITT (heparin-induced thrombocytopenia thrombosis). HITT is when clots form in both the venous and arterial side (basically clots can form anywhere vs VTE where clots only found in venous system)
HIT treatment: stop all forms of heparin and LMWH (including heparin flushes). Stop warfarin and reverse it. Use a direct thrombin inhibitor such as argatroban. Restart warfarin at a lower dose (5mg or less) and platelets have recovered to at least 150,000/mm3
A patient has developed heparin-induced thrombocytopenia (HIT). He requires anticoagulation therapy for a pulmonary embolism. Which of the following agents would not pose a risk for HIT in this patient?
A. Enoxaparin
B. Argatroban
C. Dalteparin
D. Heparin
E. None of the above
B. Argatroban is FDA approved for use in HIT and is recommended first-line by the CHEST guidelines.
IV Direct Thrombin (IIa) Inhibitors: directly inhibit thrombin (Factor IIa). used in patients with a history of HIT. CI: active major bleed. SE: bleeding, anemia, hematoma, pregnancy (B). No cross reaction with HIT. Not antidote.
argatroban: drug of choice in HIT. must be protected from light during administration. decrease dose in hepatic impairment
bivalirudin (Angiomax): used in cardiac cath lab. decrease dose when CrCl <30
Both agents: HIT dosing (initial 2mcg/kg/min, titrate to target aPTT, max 10mcg/kg/min). PCI (IV bolus followed by infusion, all are weight-based)
