Hypoalbuminemia and Beta-Lactam Dosing: Why ID Experts Disagree

In an interview with Pharmacy Times, Christina O'Connor, PharmD, BCPS, RPh, BCIDP, an infectious disease clinical pharmacist at Mayo Clinic in Rochester, Minnesota, discussed why dose adjustment for hypoalbuminemia remains a debated question in infectious diseases, how low albumin may affect highly protein-bound antimicrobials, and why she focused her discussion on ertapenem (Invanz) and ceftriaxone. The discussion is based off her presentation during the “Treatment Conundrums—Not Always Black & White” session at IDWeek 2026, taking place October 21–24 in Washington, DC.

O'Connor described 2 schools of thought. In the first, low albumin meaningfully reduces free antibiotic exposure: for drugs that are highly bound to albumin, more unbound drug circulates when albumin is low, that free drug is cleared through elimination pathways, and less active drug remains available. In the second, free drug exposure is not meaningfully influenced by albumin level. Although more drug is unbound, clearance increases only enough to maintain the normal free concentration, so free drug exposure stays the same even as total drug concentrations may fall. O'Connor noted that substantial literature, and strong opinions, support both camps.

She illustrated the debate with ceftriaxone (Rocephin; Roche), which she described as about 80% to 90% protein bound, mainly to albumin. Under the first view, faster clearance of free ceftriaxone in patients with low albumin could shorten the time that free drug concentrations stay above the minimum inhibitory concentration (MIC), meaning clinicians may not reach the pharmacokinetic/pharmacodynamic target needed for efficacy. Under the second view, free drug time above the MIC is maintained across the dosing interval, and efficacy would not be affected. She noted that most of the evidence in this area involves beta-lactam antibiotics.

O'Connor said she focused on ertapenem (Invanz; Merck) and ceftriaxone after a recent study in Clinical Infectious Diseases examined this question specifically for ertapenem and because ceftriaxone is commonly used in intensive care units to treat gram-negative infections. She acknowledged a separate body of research and similar debate on cefazolin and other gram-positive agents, particularly in bacteremia and endocarditis.¹

REFERENCE

1. Jung E, Park JJ, Oh HS, Jung Y. Absence of significant interaction between serum albumin level and carbapenem type on 30-day mortality in ESBL-positive E. coli and K. pneumoniae bacteremia: A multicenter cohort study with inverse probability of treatment weighting analysis. Clin Infect Dis. 2026;ciag444. doi:10.1093/cid/ciag444