EC is a 67 year-old female seen in the medical ward after being admitted approximately 72 hours ago for bacteremia secondary to a UTI.  The blood cultures recently finalized with E. coli growing in 2/2 sets.  The patient was started on Unasyn in the ED but was switched to ceftriaxone after the susceptibilities came back showing resistance to Unasyn.

PMH: CKD stage 4, T2DM, HTN, HLD

Vitals:

Ht: 64 in

Wt: 68.5 kg

Temp: 99.6 F

BP: 134/89 mmHg

HR: 84 bpm

RR: 18 bpm

Labs:

SCr: 1.7 mg/dL (baseline: 1.7 mg/dL)

CrCl: 27.7 mL/min

The hospitalist wants to keep EC inpatient for an additional 48 hours, definitive IV antibiotics before being discharged on oral antibiotics for the rest of the treatment duration.  Since EC is going to be staying for at least another 48 hours, the hospitalist wants to start her on VTE prophylaxis.  Which option would be most appropriate for this patient?

A. Sequential compression devices

B. Rivaroxaban 15mg PO daily

C. Heparin 5000 units sq q8h

D. Lovenox 40 mg sq daily

Answer with rationale:

Virchow’s Triad describes 3 of the primary factors that can contribute to the formation of a thrombus.  These 3 factors include vascular wall injury (surgery, trauma), hypercoagulability (pregnancy, cancer, thrombophilia), and venous stasis (immobility, chronic venous insufficiency).  Almost all hospitalized patients have at least one of these risk factors– most commonly, immobility.  While admitted, patients are performing less of their usual activities of daily living and spend most of their time in bed.  Due to this decrease in movement, blood can pool in the lower extremities and lead to clot formation (i.e., deep vein thrombosis).  Sometimes the clot can travel to the lungs causing a blockage in the pulmonary artery which is known as a pulmonary embolism.  VTE prophylaxis is used to prevent this from occurring.  There are 2 main forms of VTE prophylaxis: mechanical and chemical.  Mechanical VTE prophylaxis includes intermittent compression devices (ICD), sequential compression devices (SCD), and graduated compression stockings (GCS).  Chemical VTE prophylaxis includes anticoagulants like unfractionated heparin (UFH), low molecular weight heparin (LMWH), DOACs, etc.  Patient specific factors can help determine which method to use.

Answer A is incorrect.  This answer is incorrect because EC has no known contraindications to chemical prophylaxis which would be preferred. Mechanical prophylaxis can be given with chemical prophylaxis but would not be given alone.  In addition, during this 72 hour time period that EC has been hospitalized, she could have developed a DVT and applying any of the mechanical prophylactic devices could cause the clot which may have formed to dislodge leading to a PE.  An ultrasound would be needed to rule out active VTE before starting mechanical prophylaxis.

Answer B is incorrect. While rivaroxaban has been approved for use as VTE prophylaxis in acutely ill medical patients, 15 mg po daily is the appropriately adjusted renal dose for treating atrial fibrillation. The correct dosing regimen for VTE prophylaxis should be 10mg once daily with or without food. Keep in mind that all treatment doses of rivaroxaban require food to be administered with the dose to ensure good absorption (e.g. 20mg once daily)

Answer C is correct.  Unfractionated heparin is given subcutaneously for VTE prophylaxis and can either be given every 8 hours or every 12 hours.  UFH also does not require any renal dose adjustments, so it is often preferred in patients with chronic kidney disease and/or AKI.

Answer D is incorrect.  This answer is incorrect because EC’s CrCL is <30 mL/min meaning the correct dose of Lovenox would be 30 mg sq daily.  A dose of 40 mg sq daily would be correct if her CrCl was ≥30 mL/min.

Brands/generics covered:

Rocephin (ceftriaxone), Unasyn (ampicillin/sulbactam), Xarelto (rivaroxaban), heparin, Lovenox (enoxaparin)

NAPLEX content domains covered:

2.A.2

Domain 2 Medication Use Process- A. Prescriptions and medication order interpretation 2. Indications, usage, and dosing regimens

3.C.2

Domain 3 Person-Centered Assessment and Treatment Planning- C. Patient health conditions 2. Appropriateness of therapy