In this episode, I’ll:
1. Discuss an article about using fondaparinux in critically ill patients with severe renal dysfunction.
2. Answer the drug information question “Why is clindamycin added to antibiotic coverage in necrotizing fasciitis?”
3. Share a resource to make your midyear poster presentation easier to read.
Article
Lead author: Krista A. Wahby
Published in Pharmacotherapy August 2017
Background
Evaluating options for venous thromboembolism (VTE) prophylaxis in critically ill patients is challenging. Renal failure, bleeding risk, and thrombocytopenia can limit available pharmacotherapy options. Fondaparinux use is often limited in critically ill patients due to it’s contraindication in severe renal dysfunction (SRD). The authors of this study evaluated antifactor Xa levels in critically ill patients with SRD who were receiving an extended interval dosing regimen of fondaparinux for VTE prophylaxis.
Methods
The study was a prospective, single arm, interventional study. Patients were enrolled from two academic hospitals of the Detroit Medical Center. Only ICU patients with an estimated creatinine clearance less than 30 ml/min were enrolled. These included patients with acute kidney injury or end-stage renal disease. Fondaparinux was given at a dose of 2.5 mg subcutaneously every 48 hours. Peak and trough antifactor Xa levels were monitored. Ultrasound was used at baseline and study completion to assess for deep vein thrombosis (DVT). Bleeding complications were also recorded.
Results
Thirty-two patients received a median of 4 doses of fondaparinux. Fondaparinux peak and trough antifactor Xa levels were 0.36 ± 0.18 mg/L and 0.17 ± 0.11 mg/L (mean ± SD), respectively. These levels are similar to those in patients with normal renal function receiving conventional once-daily dosing. No lower extremity DVTs or suspected VTE events occurred. Two patients (6%) had significant bleeding events.
Conclusion
The authors concluded:
In critically ill patients with SRD, an extended interval fondaparinux dosing regimen of 2.5 mg every 48 hours for VTE prophylaxis achieved peak and trough antifactor Xa levels similar to those reported in noncritically ill patients with normal renal function receiving once-daily fondaparinux. This regimen offers an alternative for patients with SRD when heparinoids must be avoided.
Discussion
I can’t count the number of times I wanted to use fondaparinux for an ICU patient but couldn’t due to renal dysfunction. This is an important study to consider if you have a patient with a history of heparin induced thrombocytopenia that is at high risk of VTE. The sample size of this study was small, and the bleeding incidence of 6% was not compared against a placebo group. This precludes the study results from being broadly applied to all ICU patients. However, I would consider this regimen in uniquely complex patients with high clotting risk, renal dysfunction, and the need to avoid heparin.
Drug information question
Q: Why is clindamycin added to other antibiotics when treating necrotizing fasciitis?
A: To reduce toxin production.
Clindamycin is bacteriostatic and is not appropriate for monotherapy in a serious infection such as necrotizing fasciitis. The toxin produced by bacteria such as group A Strep in necrotizing fasciitis is protein-based. Through its effects inhibiting protein synthesis, clindamycin suppresses toxin production and can lessen the systemic response to infection. Linezolid also has a similar effect on reducing toxin production and can be used in place of clindamycin.
Resource
Communicating the technical details of a research project in poster format is challenging. Add to that a word limit and it gets even harder to make your point. The Hemmingway app is a free browser-based tool that can make your writing bold, clear, and easy to read.
Start by copying and pasting your text into the app. Next, follow the instructions in the sidebar. The app will help you simplify phrases, avoid passive voice, reduce adverb use, and improve readability. Pay special attention to reducing dense, complicated sentences. This will make your poster easier to read at Midyear.
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.
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