INTRODUCTION: Dalbavancin is a lipoglycopeptide with an exceptionally long half-life that allows simplified administration, which may be of value in long-term treatment of bone and joint infections, such as prosthetic joint infections (PJIs). The objective was to determine trough (Cmin) values of dalbavancin during long-term PJI treatment according to the recommendation of the Swedish National Guidelines for Bone and Joint Infections: a loading dose of 1,500 mg on day 1 and another 1,500 mg on days 8-14, followed by day 28 administration of 1,000 mg every two weeks or 500 mg per week. PATIENTS/
METHODS: Twelve patients with PJI treated with at least six doses of dalbavancin were prospectively followed up, serum samples were collected, and renal function was investigated. Dalbavancin concentrations were measured using ultra-high pressure liquid chromatography coupled with unispray tandem mass spectrometry (UHPLC-MS/MS).
RESULTS: The median serum concentration (Cmin) 14 days after the first 1,500 mg dose was 36.3 mg/L (range: 6.6-62.4 mg/L). The median trough value at the date of the last given dose (1,000 mg) after a total of 6-7 doses was 53.6 mg/L (range: 32.0-97.5 mg/L). Three patients showed a tendency towards successive accumulation of dalbavancin during treatment. None of the patients showed any significant impairment in renal function.
CONCLUSIONS: Therapeutic drug monitoring during long-term dalbavancin treatment is recommended to avoid the risk of accumulation and unnecessarily high trough levels. In many cases, such monitoring can allow the dosing interval to be extended.