Daptomycin (Prosthetic Joint Infections — Gram-positive)

How it works

It inserts into the Gram-positive bacterial cell membrane in a calcium-dependent manner, causing rapid membrane depolarisation and loss of membrane potential that leads to concentration-dependent bactericidal killing.

Prescribing in practice

• Daptomycin can cause myopathy and rarely rhabdomyolysis — monitor creatine kinase, ask about muscle pain or weakness, and consider stopping interacting myotoxic drugs such as statins during treatment.
• It must not be used for pneumonia because it is inactivated by pulmonary surfactant, and it can rarely cause eosinophilic pneumonia which warrants stopping the drug.
• Dosing is weight-based and the interval is extended in significant renal impairment; follow specialist microbiology and the SPC, as it is given by injection only.

Monitoring

Monitor creatine kinase regularly during treatment and assess renal function, with vigilance for muscle symptoms and respiratory deterioration.

Counselling the patient

• Report muscle pain, tenderness or weakness during treatment.
• Report new breathlessness, fever or cough, which need assessment.
• Attend for the blood tests arranged to monitor this antibiotic.

Evidence & guidelines

Specialist bone and joint infection guidance positions daptomycin as an option for Gram-positive prosthetic joint infection, with creatine kinase monitoring recommended in the SPC.