As an infectious disease pharmacist, you will hear controversy over the best way to treat patients hospitalized with pyelonephritis. There's limited evidence to guide empiric antibiotic choices in these patients and growing concerns about resistance to commonly used antibiotics, such as quinolones. Use your antibiogram to choose an antibiotic with good empiric coverage of E. coli, the culprit in most pyelonephritis cases...
Generally, start empiric treatment with IV ceftriaxone (Rocephin, Wintriaxone) 1 to 2 gm once daily as long as local E. coli resistance is low, such as less than 10%. Consider piperacillin/tazobactam (Tazocin, Pipra-Taz) or cefepime (Maxipime, Pimfast) for patients at risk for Pseudomonas or other resistant organisms. Risks may include prior resistant pathogens, hospitalization or antibiotic use within the past 3 months or obstruction or other urologic abnormalities.
Save carbapenems (meropenem, etc) for empiric extended-spectrum beta-lactamase (ESBL) coverage in hemodynamically unstable, septic patients or those with a previous ESBL infection. Generally, avoid empiric methicillin-resistant Staph aureus (MRSA) coverage if the kidneys are the only suspected infection source.
Switch to an oral antibiotic based on susceptibility results once your patient is afebrile for 24 to 48 hours. If susceptible, lean toward TMP/SMX (Septrin DS) one tab every 12 hours or a beta-lactam (Augmentin) 1 gm every 8 hours for 10 to 14 days due to quinolone adverse effects. But consider just 7 days of TMP/SMX in a patient who isn't critically ill, responds well and has close follow-up. Limited evidence suggests it might work as well as 7 days of oral ciprofloxacin. Don't use oral fosfomycin or nitrofurantoin for pyelonephritis drug levels in the kidneys aren't adequate.
REFERENCES
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Johnson JR, Russo TA. Acute Pyelonephritis in Adults. N Engl J Med. 2018 Jan 4;378(1):48-59. Available at: https://www.nejm.org/doi/full/10.1056/nejmcp1702758
Gupta K, Hooton TM, Naber KG, Wullt B, Colgan R, Miller LG, Moran GJ, Nicolle LE, Raz R, Schaeffer AJ, Soper DE; Infectious Diseases Society of America; European Society for Microbiology and Infectious Diseases. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clin Infect Dis. 2011 Mar 1;52(5):e103-20. Available at: https://academic.oup.com/cid/article/52/5/e103/388285?login=false
Sanchez M, Collvinent B, Miró O, Horcajada JP, Moreno A, Marco F, Mensa J, Millá J. Short-term effectiveness of ceftriaxone single dose in the initial treatment of acute uncomplicated pyelonephritis in women. A randomised controlled trial. Emerg Med J. 2002 Jan;19(1):19-22. Available at: https://emj.bmj.com/content/19/1/19.long
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