Within severely ill patients, the linezolid concentration-time profile showed a large variation. It was interesting to find out if there was any correlation between the site of infection and the linezolid serum concentrations. There were a total of 68 critically ill patients who were given linezolid treatment. They were able to determine the linezolid concentration-time profile by making use of maximum a-posteriori predictions. The aim was a trough concentration (Cmin) between 2 and 10 mg/L. Using a generalized linear model (GLM), potential covariates were evaluated. Peritonitis (38.2%), pneumonia (25.0%), infectious acute respiratory distress syndrome (ARDS) (19.1%), and other non-pulmonary infections (17.7%) were the most common indications for linezolid therapy. About 27.2% of Cmin was subtherapeutic, whereas 7.9% was hazardous. ARDS (mean: −2.1 mg/L, CI: −3.0 to −1.2 mg/L) and pneumonia (mean: −2.2 mg/L, CI: −2.8 to −1.6 mg/L) were significant (P<0.001) determinants of Cmin in the GLM. Patients with ARDS (mean: 2.3 mg/L; 51.2% subtherapeutic; 0.0% toxic) and pneumonia (mean: 3.5 mg/L; 41.5% subtherapeutic; 7.7% toxic) had significantly (P<0.001) lower Cmin levels than those with peritonitis (mean: 5.5 mg/L; 14.4% subtherapeutic; 9.3% toxic) and other non-pulmonary infection (mean: 5.2 mg/L; 3.3% subtherapeutic, 16.5% toxic). Patients diagnosed with lung infections had lower serum amounts of the antibiotic linezolid. Because of the accumulation of linezolid in the lungs, additional research should be conducted in the future to identify whether or not these patients require different linezolid thresholds.

SOURCE – sciencedirect.com/science/article/abs/pii/S0883944122001290