The ‘double hit’ on dalbavancin pharmacokinetics: hypertriglyceridaemia and augmented renal clearance in a child with glycogen storage disease type Ib

Dalbavancin is increasingly used in paediatrics due to its prolonged half-life, which facilitates outpatient management of Gram-positive infections. However, current pharmacokinetic (PK) data are largely derived from single-dose studies in homogeneous populations.1,2 We report a case of marked dalbavancin PK variability in a child with glycogen storage disease type Ib (GSD-Ib), driven by the synergistic effect of metabolic dysregulation and augmented renal clearance (ARC). A 6-year-old boy (22 kg) with genetically confirmed GSD-Ib presented with fever and left orbital cellulitis. He was on chronic dapagliflozin therapy for neutropenia and exhibited marked hypertriglyceridaemia (500 mg/dL), a hallmark of his metabolic disorder.3 CT imaging revealed an extra-conal intraorbital abscess with distinct demineralization of the lamina papyracea and medial orbital wall, suggestive of bone involvement. Following endoscopic drainage, cultures yielded penicillin-resistant Streptococcus mitis/oralis. To facilitate discharge without central venous access, while ensuring prolonged coverage consistent with the management of early osteomyelitis, an off-label multidose dalbavancin regimen was initiated.