Oritavancin

• Brand names: Orbactiv, Kimyrsa
• Route: Intravenous

Oritavancin binds cell-wall precursors like other glycopeptides, but also inhibits transglycosylation and transpeptidation directly.

Its hydrophobic side chain additionally disrupts the bacterial membrane, making it bactericidal rather than merely inhibitory.

The three mechanisms together retain activity against vancomycin-intermediate and vancomycin-resistant organisms.

• A single 1,200 mg intravenous dose infused over 3 hours (Orbactiv) or 1 hour (Kimyrsa reformulation).
• No dose adjustment for mild to moderate kidney or liver impairment.
• Unfractionated heparin must be avoided for 48 hours afterwards because oritavancin distorts the aPTT test for up to that long, and prothrombin time for up to 24 hours.
• The terminal half-life is around 245 hours, so a single dose covers the full treatment course.

Doses listed are typical adult regimens quoted for reference. The actual dose, route and duration are decided by a clinician for the individual patient.

Oritavancin was derived from chloroeremomycin, a natural glycopeptide, by Eli Lilly in the 1990s.

It passed through InterMune and Targanta before Medicines Company completed development, and was approved by the FDA in 2014.

A reformulated one-hour infusion, Kimyrsa, was approved in 2021.

• Nausea, vomiting, headache and diarrhoea.
• Infusion-site reactions and hypersensitivity, including flushing during the infusion.
• Interference with coagulation tests; osteomyelitis was reported more often in the trial arm, so it is not recommended when bone infection is suspected.

• Skin infection caused by streptococci and vancomycin-susceptible Enterococcus faecalis.
• Occasional off-label use where a single-dose treatment avoids admission.