Therapeutic Drug Monitoring Versus Fixed-Interval Dosing of Dalbavancin in Implant-Associated Spinal Infections: Grand Round/A Case Study

BACKGROUND: Implant-associated spinal infections (IASI) pose challenges for outpatient management due to the need for frequent intravenous antibiotic administration. Dalbavancin has a prolonged half-life and is a practical alternative. METHODS: Two cases of IASI were treated with dalbavancin in an outpatient setting over 10-12 weeks. One patient received therapeutic drug monitoring (TDM)-guided dosing, while the other was managed with fixed-interval dosing. Dalbavancin plasma concentrations were measured using liquid chromatography-tandem mass spectrometry, and dosing adjustments were guided by pharmacokinetic modeling. RESULTS: In the TDM-guided case, three dalbavancin doses were sufficient to maintain therapeutic plasma concentrations (≥8 mg/L), whereas the fixed-interval approach required four doses. Both patients successfully completed therapy without recurrence of the infection during follow-up. CONCLUSIONS: TDM-guided dalbavancin therapy optimized drug exposure and reduced the number of doses compared with fixed-interval dosing, highlighting its potential to optimize treatment. Further research is required to establish standardized therapeutic drug monitoring protocols for the management of IASI.