Incidence and associated risk factors for systemic drug levels with inhaled aminoglycoside therapy

Objectives To characterize the incidence of and risk factors for a detectable drug level (DDL) in patients that received inhaled aminoglycoside therapy. Methods This retrospective, single-centre study included adult patients who received at least one dose of an inhaled aminoglycoside with a drug level during inpatient hospitalization. Patients were excluded if they received an aminoglycoside intravenously within 7 days or if the drug level was not drawn within 4 h of the next dose. A repeated measures logistic regression model evaluated the association between potential risk factors and a DDL. Results Among 286 drug levels, 88 (30.8%) drug levels were detectable. In multivariable analysis, cystic fibrosis (CF) (OR: 3.03; 95% CI: 1.10-8.35), chronic kidney disease (CKD) (OR: 4.25; 95% CI: 1.84-9.83), lung transplant recipient (OR: 3.08; 95% CI: 1.09-8.73), mechanical ventilation (OR: 2.99; 95% CI: 1.25-7.15) and tobramycin (OR: 5.26; 95% CI: 2.35-11.78) were associated with higher odds of a DDL. Among those with a DDL, inhaled aminoglycoside type and drug level concentration were not associated with acute kidney injury (P = 0.161). Conclusions Among 286 drug levels identified among inpatients receiving inhaled aminoglycoside therapy, 88 (30.8%) unique drug levels were detectable. Based on the results of this study, periodic trough concentrations should be considered for patients receiving inhaled aminoglycoside therapy with CF, CKD, lung transplantation, mechanical ventilation or tobramycin.

Automated summary

This study investigated the incidence and risk factors for detectable drug levels in patients receiving inhaled aminoglycoside therapy. The results showed that certain factors, such as cystic fibrosis, chronic kidney disease, lung transplantation, mechanical ventilation, and the use of tobramycin, were associated with a higher likelihood of detectable drug levels.