Antibiotic Stewardship at SSRRH (Nadeau, 1/26/2022)

The Adult Medicine Service of the Santa Rosa Family Medicine Residency have had the honor and privilege of rounding daily with the SSRRH Pharmacists for the last 4+ years, and we are better physicians for it! This week, Sue Nadeau, one of our wonderful pharmacists, gave us an important Grand Rounds on Antibiotic Stewardship at SSRRH.

To watch the presentation, please click HERE.

The presentation covered 4 important topics in antibiotic stewardship, and 1 on anticoagulation (because you cannot NOT talk about warfarin, even in 2022)

• QT prolongation
• Warfarin
•  Extended-spectrum beta lactam (ESBL) E Coli
• Extended infusions of beta lactam antibiotics
• IV to oral antibiotics

QT Prolongation  or long QT syndrome (LQTS) is a disorder of myocardial repolarization characterized by a prolonged QT interval on EKG. 

• LQTS is associated with an increased risk of polymorphic ventricular tachycardia, a  life-threatening cardiac arrhythmia aka torsade de pointes 
• Primary symptoms include palpitations, syncope, seizures, and sudden cardiac death.
• For men, normal QTc is ~350-450
• For women, normal QTc is ~360-460

Some of the long list of drugs that affect QT

There are LOTS of meds that lengthen the QTc, and the most commonly rx'd antibiotics are azithromycin, ciprofloxacin, and fluconazole (see chart for additional culprits)

Tips to avoid QT prolongation: 

1) Check EKG on admission (QTc>500 should definitely get your attention)

2) Review chronic medications that prolong QT (e.g. cardiac, antipsychotics, SSRI, TCA, oral cancer meds, HIV meds). Hold if needed

3) Check electrolytes: potassium and magnesium (normal levels decrease risk of Torsade)

4) Check renal function (and dose adjust if indicated)

5) Call the pharmacist for any questions

And. . .whenever possible do NOT use azithromycin or ciprofloxacin, particularly in high risk 

Warfarin is metabolized in the liver via cytochrome P450 

• Drug interactions occur when meds compete for the same enzyme system
• We all know that drugs interactions are a BIG deal with warfarin
• Drugs well known for warfarin interactions: amiodarone, metronidazole, Bactrim (aka TMP/SMX), fluconazole, voriconazole, macrolides (including azithromycin, though in the literature less often)

ESBL E Coli

• In the Sutter system, ceftriaxone (Rocephin) resistance seen on the sensitivities report in any E Coli is a proxy marker for ESBL
• Our E Coli has gone from 95% to 93% sensitive to Rocephin, new antibiogram will be out in the spring (April)
• Meropenem (with ID approval) is the medication of choice, EVEN if the E Coli appears to be sensitive to fluoroquinolones

Extended infusion of beta lactam antibiotics-- for pip/taz, cefepime, and meropenem

• Beta lactam antibiotics are bactericidal just during the administration, but stopping a 30 minute admin can allow an organism to quickly begin to replicate
• Extended duration infusions (usually 4 hours) have been shown to decrease bacterial load and improve outcomes
• Currently these happen for ICU patients with the above abx, but can be ordered for non-ICU patients if deemed clinically indicated (e.g. quite sick, still spiking fevers, etc)
• need to discuss with bedside RN because infusion will use the line for long periods of time, sometimes patients need an additional line
• These are 4 hour infusions q8 hours

IV to Oral antibiotics

Oral is better! Decreased risk of line infections, decreased risk of thrombophlebitis, decreased cost (of actual medication as well as nursing and admin costs), earlier discharge

We should really be thinking about transitioning to PO abx as soon as we can. Here are guidelines:

• Afebrile x24 hours
• Blood cultures no growth x48 hours
• Tolerating PO diet
• Improved clinical status
• Normal or decreasing WBC count
• Hemodynamically stable (e.g. normal vital signs x 24 hours)

We are SO blessed at SSRRH to have the benefit of a number of pharmacy-driven protocols, including:

• Dose adjustments (primarily renal, but occasional hepatic)
• Dose optimization (e.g. gentamicin, vancomycin by protocol)
• Automatic alerts
• Automatic stop orders (e.g. azithromycin x 5 days, oseltamivir x 5 days)
• Drug drug interaction checks
• Shortest effective duration

Thanks to Sue, Carolyn Dam, and the whole pharmacy team for their amazing collaboration in caring for our patients!