Dalbavancin

Dalbavancin is a long-acting lipoglycopeptide given as one or two infusions, with activity against MRSA and other Gram-positive cocci. It is licensed for skin and skin structure infection and used off-label for bone, joint and endovascular infection when long courses at home are impractical.

Classification. Lipoglycopeptide.

Mechanism. Binds the D-alanyl-D-alanine terminus of cell wall precursors and anchors to the membrane through a lipophilic side chain, blocking cell wall synthesis.

Spectrum. MRSA, MSSA, streptococci, vancomycin-susceptible enterococci. Not active against vanA vancomycin-resistant enterococci or Gram-negative bacilli.

Pharmacokinetics. IV only. Terminal half-life about 14 days. Protein binding 93%. About 45% excreted unchanged in urine and 20% in faeces.

Availability in East Africa is very limited. No separate loading dose.

Adults, acute bacterial skin and skin structure infection. Either a single 1500 mg IV infusion over 30 minutes, or 1000 mg on day 1 and 500 mg on day 8.

Off-label (specialist). - Bone and joint infection, osteomyelitis, prosthetic joint infection, bacteraemia and endocarditis: 1500 mg on days 1 and 8, with a repeat every 2 to 6 weeks in some regimens, directed by infectious diseases.

Children. From birth to under 6 years: 22.5 mg/kg single dose; 6 years to under 18 years: 18 mg/kg single dose (maximum 1500 mg), in labelled paediatric use for skin infection.

Alternatives. Vancomycin, teicoplanin, linezolid, daptomycin, oritavancin.

Contraindications. Hypersensitivity to dalbavancin.

Adverse effects. Nausea, headache, diarrhoea, rash, infusion-related flushing, raised liver enzymes, hypersensitivity, Clostridioides difficile infection.

Interactions. No clinically important cytochrome P450 interactions.

Common prescribing errors. Reconstituting or diluting in saline (use 5% glucose only), giving over less than 30 minutes, and not considering renal dose reduction.

Special groups. - Pregnancy and breastfeeding: limited data; use only if needed. - Older adults: no adjustment unless kidney function is poor. - Kidney impairment: creatinine clearance under 30 mL/min not on haemodialysis give 1125 mg once, or 750 mg then 375 mg a week later. Haemodialysis: no adjustment. - Liver impairment: no adjustment in mild disease; limited data in severe disease.

Preparation. Reconstitute only with sterile water for injection, then dilute in 5% glucose to 1 to 5 mg/mL; infuse over 30 minutes. Do not use saline for reconstitution or dilution.

Baseline and monitoring. - Baseline: allergy history, creatinine, liver tests, cultures. - During treatment: liver tests; clinical review at 1 to 2 weeks; no routine drug level.

Stop rules. Stop for anaphylaxis or severe infusion reaction.

Referral and escalation. Infectious diseases consultation is needed for every off-label use and for implant infection.