Chemical Identity

Property	Value
Chemical Formula	C86H97Cl3N10O26
Molecular Weight	1793.1 Da
CAS Number	171099-57-3
Peptide Class	Lipoglycopeptide
Origin	Semi-synthetic (from chloroeremomycin)

Structure

Oritavancin is a semi-synthetic lipoglycopeptide derived from the vancomycin-type glycopeptide chloroeremomycin. It has a 4’-chlorobiphenylmethyl substituent on the disaccharide sugar, a hydrophobic side chain that enhances membrane perturbation activity and confers a very long half-life.

Mechanism of Action

Oritavancin has three distinct mechanisms: (1) binding to D-Ala-D-Ala of lipid II to inhibit cell wall synthesis, (2) binding to D-Ala-D-Lac of vanA-mediated resistant organisms, and (3) membrane depolarization via the hydrophobic side chain. This multi-target activity prevents resistance development.

Clinical Applications

• ABSSSI: Single-dose 1200 mg IV infusion
• MRSA and VRE infections: Active against vanA VRE
• Streptococcal infections: Beta-hemolytic and pneumococcal
• Osteomyelitis: Off-label for bone infections

Pharmacokinetics

• Half-life: 245 hours (~10-14 days)
• Protein binding: 85%
• Elimination: Fecal (primarily) and renal
• Dosing: Single 1200 mg IV infusion
• Route: IV infusion over 3 hours

Safety and Side Effects

Nausea, headache, diarrhea, vomiting, and infusion site reactions. No dose adjustment for renal or mild-moderate hepatic impairment. Avoid in patients on warfarin (protein binding displacement).

References

• Corey, G.R., et al. (2014). Single-dose oritavancin for ABSSSI. New England Journal of Medicine, 370, 2180-2190.
• Zhanel, G.G., et al. (2012). Oritavancin: mechanism of action. Clinical Infectious Diseases, 54, S214-S219.