The New Community-Acquired Pneumonia Guidelines are Finally Here!

Today’s pearl is a brief overview the Infectious Diseases Society of America (IDSA) and American Thoracic Society (ATS) update to the Adult Community-Acquired Pneumonia (CAP) guidelines, with a focus on medications.

After 12 long years, the highly anticipated update to the CAP guidelines has arrived!

The guideline is set up as 16 questions, and for each they provide a recommendation, summary of evidence, rationale, and research needed in that area. I will share their recommendation and add my thoughts, when applicable (my comments are in italics). Of note, there are additional antibiotics mentioned for some of the indications below. The ones I list are preferred based on side effect profile, drug interaction risk, local susceptibility patterns, dosing schedule, and cost. These guidelines, for the most part, do not address the prevalence of atypical bacteria in CAP and how much CAP is attributable to non-bacterial causes.

Empiric Treatment in Outpatients (Question 8)

  • No comorbidities or risk factors for antibiotic resistant pathogens:
    • Amoxicillin 1 gm TID OR Doxycycline 100 mg BID
      • Azithromycin is listed, but resistance is too high in all of the continental U.S. to use it as monotherapy
  • Comorbidities (chronic heart/lung/liver/renal disease; diabetes; malignancy; asplenia)
    • Combination:
      • Amoxicillin/Clavulanate 875/125 mg BID OR Cefpodoxime 200 mg BID OR Cefuroxime 500 mg BID
        • Consider cefpodoxime 400 mg BID in patients with average or higher body weight
      • PLUS azithromycin 500 mg X 1, then 250 mg daily OR Doxycycline 100 mg BID
    • Monotherapy: Levofloxacin 750 mg daily OR Moxifloxacin 400 mg daily
      • FQs have several black box warnings, other serious adverse reactions, and drug interactions – use combination therapy above unless patient absolutely can’t tolerate

Empiric Treatment in Inpatients (Questions 9 & 11)

  • Non-severe without MRSA or P. aeruginosa risk factors: Ceftriaxone 1-2 gm QDAY PLUS Azithromycin 500 mg QDAY
    • FQs are listed for monotherapy, but should be avoided whenever possible
    • Doxycycline can be substituted for macrolides
  • Severe without MRSA or P. aeruginosa risk factors: Same as non-severe. If using a FQ, add beta-lactam as well.
    • Avoid FQs whenever possible
  • With MRSA or P. aeruginosa risk factors: As was alluded to in the 2016 Hospital-Acquired and Ventilator-Associated Guidelines, there is no more HCAP. The new guidelines recommend only covering empirically for MRSA or P. aeruginosa “if locally validated risk factors for either pathogen are present.” Vancomycin or Linezolid for MRSA, when indicated. Cefepime or Piperacillin/Tazobactam for P. aeruginosa, when indicated.

Aspiration in Inpatients (Question 10)

  • Do not routinely add anaerobic coverage unless lung abscess or empyema is suspected. Standard inpatient CAP therapy above is sufficient.

Corticosteroids (Question 12)

  • Do not routinely use steroids in CAP (non-severe or severe) or severe influenza pneumonia. Follow Surviving Sepsis Campaign recommendations in refractory septic shock.

Concomitant Influenza (Questions 13 & 14)

  • Guidelines recommend anti-influenza treatment in CAP patients testing positive for influenza, in inpatients and outpatients, independent of duration of illness before diagnosis. [Data on antivirals is controversial, but IDSA and CDC both support their use]
  • Guidelines recommend antibacterial treatment be initially prescribed for adults with clinical and radiographic evidence of CAP who test positive for influenza in the inpatient and outpatient settings.

Duration of Treatment (Question 15)

  • At least 5 days with discontinuation guided by a validated measure of clinical stability.


Author: Bryan D. Hayes, PharmD

Attending Pharmacist, Emergency Medicine and Toxicology, Massachusetts General Hospital; Assistant Professor of EM, Harvard Medical School

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