In this episode I’ll:
1. Review the updated CHEST guidelines on Antithrombotic Therapy for VTE Disease.
2. Answer the drug information question: “Can I continue metronidazole for prevention of recurrent clostridium difficile infection (CDI) in patients requiring antimicrobial therapy?”
3. Share a resource I wear around my wrist.
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Shout out to Pharmacy Nation member Noha for suggesting this article for review!
Article
The American College of Chest Physicians have recently published the 10th edition of their guidelines on Antithrombotic Therapy for VTE Disease. This edition of the guidelines continues the use of the GRADE methodology to describe the quality of the evidence and the strength of the recommendation for each guideline statement.
The 9th edition of the CHEST guidelines on Antithrombotic Therapy for VTE Disease was published in 2012. The guideline authors made at the time several innovative changes to the way their guidelines were structured. Three notable changes were
1. Prominently taking patient values and preferences into account in the guideline recommendations.
2. A series of podcasts were released with the AT9 guideline publications explaining the new approach to guideline development and highlighting the new recommendations compared to the previous version.
3. Providing a more critical bias-free look at the evidence which resulted in the weakening of many guideline recommendations.
The second change turned out to be of critical importance. We are in the age of guideline-based quality metrics deciding payment. Giving controversial evidence a strong recommendation results in front-line providers and patients being placed in no-win situations. One need look no further than the sepsis quality measures and the ridiculous mess this has created as proof of the need to reserve strong recommendations for when the evidence is uncontroversial. For a great review of what happens when poor evidence creeps into strong guideline recommendations check out the post titled “We Are Complicit” by Scott Weingart at EMCrit.org.
The 2016 publication of the 10th edition of the CHEST guidelines on Antithrombotic Therapy for VTE Disease builds on the excellence of the 9th edition with this major change:
The CHEST guidelines on Antithrombotic Therapy for VTE Disease will transition to an online “Living Guidelines Model”. We’ve already seen this happen with the CPR guidelines and I’ve discussed this concept a bit in episode 26. Guidelines quickly become outdated and irrelevant as new evidence becomes available. Moving to this model will allow the guidelines to keep up with the pace of scientific discovery. As the authors state:
This new model fundamentally raises the bar for guideline development, dissemination, and implementation by focusing on specific portions of the AT guideline that require updating and will most likely alter approaches to guideline development for other professional societies in coming years.
As of this recording the guidelines are available online in a pre-publication online first pdf document. This document is unformatted. As they did in 2012, CHEST will publish a formatted version of the guidelines with shaded text used to highlight recommendations that are new or have been changed since the 9th edition was published.
Non-vitamin K antagonist oral anticoagulants get an upgrade
The most interesting change that I’ve noticed in the new guidelines is the upgrade to the strength of the recommendation given to non-vitamin K antagonist oral anticoagulants.
For patients with deep venous thrombosis (DVT) of the leg or pulmonary embolism (PE) who do not also have cancer warfarin AND the non-warfarin oral anticoagulants dabigatran, rivaroxaban, apixaban and edoxaban now share an equal recommendation.
The AT10 guidelines give any of these oral anticoagulants a 2B recommendation to be used for 3 months. If the non-vitamin K antagonist oral anticoagulants are not chosen, warfarin is recommended to be used over low molecular weight heparins (LMWH) with a 2C recommendation.
The authors describe their reasoning for this change as follows:
Despite the lack of specific reversal agents for the NOACs, the risk that a major bleed will be fatal appears to be no higher for the NOACs than for VKA therapy.
Based on less bleeding with NOACs and greater convenience for patients and healthcare providers, we now suggest that a NOAC is used in preference to VKA for the initial and long-term treatment of VTE in patients without cancer.
The order of our presentation of the NOACS (dabigatran, rivaroxaban, apixaban, edoxaban) is based on the chronology of publication of the phase 3 trials in VTE treatment and should not be interpreted as the guideline panel’s order of preference for the use of these agents.
For patients with deep venous thrombosis (DVT) of the leg or pulmonary embolism (PE) who also have cancer, LMWH is still the preferred treatment with a 2C recommendation. However the non-vitamin K antagonist oral anticoagulants are now on equal footing with warfarin if LMWH is not used.
I discussed the idea of using rivaroxaban for PE in a patient with cancer back in episode 29.
NOAC is a dangerous abbreviation
Unfortunately it seems the guidelines contain the abbreviation “NOAC” for non-vitamin K antagonist oral anticoagulants. NOAC is on the Institute for Safe Medication Practice’s dangerous abbreviation list, because it has been misinterpreted as an order for “No anticoagulation”.
Drug information question:
Q: Can I continue metronidazole for prevention of recurrent clostridium difficile infection (CDI) in patients requiring antimicrobial therapy?
A: No, metronidazole won’t work!
This question came up in regards to a patient that needed continued antimicrobial therapy after completion of a course of metronidazole for CDI. The Infectious Disease Society of America guidelines on clostridium difficile infection provide no recommendation for prevention of recurrent clostridium difficile infection in patients requiring antimicrobial therapy.
However the guidelines do note that metronidazole won’t achieve therapeutic levels in patients who no longer have active colitis. Oral vancomycin would be the preferred agent if the duration of CDI treatment is prolonged.
Resource
I field almost as many technology questions as I do pharmacy questions.
The resource I’d like to share for this show is my smartwatch – the Pebble Time Round. This smartwatch works with apple and android phones. It is round, thin, light, and has great battery life.
It comes in several styles and colors and most importantly, it actually looks like a watch and not a rectangular hockey puck like some other smartwatches do. I now use my Pebble Time Round to time epinephrine doses during codes – this leaves my smartphone free to check IV compatibility, medication doses, or patient data.
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.
Regarding metronidazole I’d add that IDSA guidelines also discourage prolonged use due to concern for neurotoxicity: “Do not use metronidazole beyond the first recurrence of CDI or for long-term chronic therapy because of potential for cumulative neurotoxicity”.
Great point, thank you!
Thank You PharmacyJoe for CHEST Guideline update!
You are welcome, thank you for the suggestion!