oritavancin diphosphate: clinical use

Prescribing considerations

• Confirm that the infection is an acute bacterial skin or skin-structure infection with likely susceptible Gram-positive pathogens.
• Oritavancin is classified as a Reserve antibiotic in the UK AWaRe framework; apply antimicrobial stewardship and local specialist governance.
• Add suitable cover when Gram-negative or relevant anaerobic organisms are suspected.
• Review previous glycopeptide hypersensitivity because cross-reactivity cannot be excluded.
• Clinical experience is limited in severe renal impairment, bacteraemia, neutropenia, peripheral vascular disease, immunocompromise and some older populations.
• It is not an appropriate treatment for suspected or confirmed osteomyelitis; use alternative antibacterial management if this is identified.

Contraindications and cautions

• Hypersensitivity to oritavancin or an excipient.
• Intravenous unfractionated heparin during the 5-day period after administration because aPTT monitoring is unreliable.

Monitoring

• Observe during and after infusion for hypersensitivity and infusion-related reactions.
• Assess clinical response and investigate new abscesses, worsening cellulitis or features of osteomyelitis.
• Evaluate significant diarrhoea for Clostridioides difficile-associated disease.
• Account for test-specific coagulation-assay interference and use an unaffected method when necessary.
• When combined with susceptible narrow-therapeutic-index medicines, monitor for toxicity or loss of efficacy.

Clinical pharmacology

Oritavancin inhibits transglycosylation and transpeptidation during bacterial cell-wall synthesis and disrupts membrane integrity. It is highly protein bound, extensively distributed, not detectably metabolised in human liver microsomes and slowly excreted unchanged, with a prolonged terminal half-life.

Formulation and product differences

• The selected powder-for-concentrate presentation has product-specific reconstitution, dilution, compatibility and infusion instructions.
• Do not interchange its preparation instructions with those for the other Tenkasi presentation.
• For the selected formulation, glucose 5% is the required diluent; sodium chloride solution is incompatible.

Solution for infusion

Route: Intravenous

Strengths: 400 mg