UMEM Educational Pearls

Category: Pharmacology & Therapeutics

Title: Beta-Lactams in Critically Ill Patients: Current Dosing May be Inadequate

Keywords: beta-lactam, piperacillin/tazobactam, critically ill (PubMed Search)

Posted: 9/27/2014 by Bryan Hayes, PharmD (Emailed: 10/4/2014) (Updated: 10/4/2014)
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Beta-lactam antimicrobials (penicillins, cephalosporins, and carbapenems) are frequently used for empiric and targeted therapy in critically ill patients. They display time-dependent killing, meaning the time the antibiotic concentration is above the minimin inhibitory concentration (MIC) is associated with improved efficacy.

Two new pharmacodynamic/pharmacokinetic studies suggest that current beta-lactam antimicrobial dosing regimens may be inadequate.

  • In patients from 68 ICUs across 10 countries, use of intermittent infusions (compared to extended and continuous infusions) and increasing creatinine clearance were risk factors for MIC target non-attainment. [1]
  • A second group specifically investigated the pulmonary penetration of piperacillin/tazobactam in critically ill patients and found that intrapulmonary exposure is highly variable and unrelated to plasma exposure and pulmonary permeability. [2]

Antimicrobial dosing in critically ill patients is complex. Current dosing of beta-lactams may be inadequate and needs to be studied further with relation to clinical outcomes.


  1. De Waele JJ, et al. Risk factors for target non-attainment during empirical treatment with beta-lactam antibiotics in critically ill patients. Intensive Care Med 2014;40(9):1340-51. [PMID 25053248]
  2. Felton TW, et al. Pulmonary penetration of piperacillin and tazobactam in critically ill patients. Clin Pharmacol Ther 2014;96(4):438-48. [PMID 24926779]

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