G. M. is a 45-year-old man presenting with a non-ST-segment-elevation myocardial infarction (MI). His creatinine clearance is estimated to be 30 mL/min. You would like to initiate eptifibatide. Which of the following doses would be the best choice?
c. Loading dose of 180 µg/kg and a maintenance dose of 1 µg/kg/min. Based on product information, eptifibatide loading dose should not be changed and the maintenance infusion should be initiated at 1 µg/kg/min. Eptifibatide is contraindicated in patients on dialysis and there is limited experience using this agent in this patient population. Tirofiban is not contraindicated in patients on dialysis; however, there are limited data to support its use in dialysis patients.
M. M. is a 39-year-old man with an inferior wall non-ST-segment-elevation MI. He has a history of poorly controlled HTN and diabetes mellitus (DM). You initiate aspirin, clopidogrel, and atorvastatin. His baseline serum creatinine is 3.4 mg/dL and you estimate his creatinine clearance to be 25 mL/min. What dose of enoxaparin would you choose?
b. Enoxaparin 1 mg/kg daily. Enoxaparin is approved for both ST-segmentelevation and non-ST-segment-elevation MI. In patients with a creatinine clearance >30 mL/min then the standard dose of 1 mg/kg every 12 hours is appropriate. However, when the creatinine clearance is <30 mL/min then the dose should be reduced to 1 mg/kg once daily. Fondaparinux is contraindicated in patients with a creatinine clearance <30 mL/min.
B. B. is a 77-year-old man who presents with typical chest pain and pressure. He has ST elevations in lead V2–4 . He is 80 kg with a serum creatinine of 0.7 mg/dL with an estimated creatinine clearance of 75 mL/min. You initiate aspirin, clopidogrel, metoprolol, and atorvastatin. You want to initiate enoxaparin and reteplase. What is the enoxaparin dose for this patient?
d. Loading dose of 30 mg IV once followed by 0.75 mg/kg every 12 hours. Enoxaparin was recently approved for the treatment of ST-segmentelevation MI with fibrinolysis based on the ExTRACT-TIMI 25 trial. In the older patients, lower enoxaparin doses were used to minimize bleeding. There was a lower risk of the primary endpoint in those that received enoxaparin versus those receiving UFH. There was no difference in intracranial hemorrhage; however, there was a significantly higher rate of major bleeding with enoxaparin (2.1% versus 1.4%).
Which of the following is not a risk factor for intracranial hemorrhage in patients receiving fibrinolytic therapy in the treatment of ST-segmentelevation MI?
d. Time to presentation. Time to presentation is not a risk factor for intracranial hemorrhage in patients receiving thrombolytic therapy. In clinical trials, the risks for intracranial hemorrhage included age older than 65 years, low body weight (<70 kg), HTN on hospital admission, and the use of alteplase. Also, the levels of concomitant anticoagulation can also increase the risk of intracranial hemorrhage.
R. M. is a 65-year-old man presenting to the emergency department (ED) with an ST-segment-elevation MI. It is decided to initiate thrombolytic therapy to induce reperfusion. The patient weighs 72 kg. What is the most effective dose of alteplase for this patient?
c. 15 mg bolus; then 50 mg over 30 minutes; then 35 mg over 60 minutes. Based on the first GUSTO trial, the most effective dosing for acute STsegment-elevation MI is front-loaded tissue plasminogen activator. The maximum dose should be 100 mg and, therefore, Answer b may increase the risk of major bleeding, specifically intracranial hemorrhage. Answer d is standard dosing of recombinant tissue-type plasminogen activator and was found inferior to front loading. Finally, Answer a is the recommended dosing for acute ischemic stroke.
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