Oritavancin

Orbactiv / Kimyrsa

Oritavancin is a semisynthetic lipoglycopeptide antibiotic used to treat acute bacterial skin and skin-structure infections (ABSSSI) caused by susceptible Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci in some cases. Like other members of its class it derives from a glycopeptide scaffold and binds the D-alanyl-D-alanine terminus of peptidoglycan precursors to block cell-wall assembly, but oritavancin has additional mechanisms: it also binds a second site on the peptidoglycan (the pentaglycyl bridge in staphylococci) and disrupts the bacterial membrane, causing depolarization and increased permeability. This multi-pronged action contributes to rapid killing and activity against some resistant organisms. Oritavancin's practical signature is that a single 1200 mg intravenous infusion delivers an entire treatment course, thanks to a very long terminal half-life. Like dalbavancin, this makes it valuable when daily dosing, prolonged IV access, or hospitalization would be difficult, letting a patient complete therapy in one visit. Its spectrum is Gram-positive only. Oritavancin is an approved prescription antibiotic (FDA 2014 as Orbactiv; a reformulated single-dose product, Kimyrsa, followed). A notable practical caution is that it artificially interferes with certain blood-clotting laboratory tests (such as aPTT and PT/INR) for a period after dosing, which clinicians must account for, and it should not be given with intravenous unfractionated heparin during that window because it can falsely elevate aPTT. As with all glycopeptide-class drugs, it is used with appropriate diagnosis and stewardship, and it is a clinician-administered medicine rather than a research or consumer peptide.