Therapeutic Drug Monitoring of Beta-Lactams in Cystic Fibrosis: Unattained Target in Standard Antibiotic Dosing

Acute exacerbations of cystic fibrosis (CF) diminish quality of life and, if inadequately treated, can be life-threatening. The pathophysiological alterations associated with CF result in modified antibiotic pharmacokinetics. Moreover, the viscous mucus in the lungs limits pathogen exposure to drugs, rendering successful antibiotic treatment challenging. A 23-year-old female patient with CF was repeatedly admitted for intravenous antibiotic therapy for acute exacerbation of Pseudomonas aeruginosa infection. In the context of altered pharmacokinetics in CF, therapeutic drug monitoring of meropenem and piperacillin revealed consistently low plasma levels of both drugs. Targeted plasma levels were ultimately achieved through continuous high-dose infusions, based on therapeutic drug monitoring and subsequent dose adjustments.