Antimicrobial
Daptomycin
A lipopeptide antibiotic that disrupts bacterial membranes, approved for MRSA bloodstream and skin infections but not pneumonia.
What it is
Daptomycin is a cyclic lipopeptide antibiotic produced by a soil bacterium (Cubicin). Its mechanism is unusual: rather than attacking the cell wall, it inserts into the bacterial membrane in a calcium-dependent way and depolarises it. It is licensed for complicated skin infection, right-sided endocarditis and MRSA bacteraemia - and specifically not for pneumonia, because lung surfactant inactivates it.
How it works
- 1
Binds bacterial membrane lipids in a calcium-dependent manner and inserts its lipophilic tail.
- 2
Depolarises the membrane, collapsing the proton motive force.
- 3
Stops protein, DNA and RNA synthesis as a downstream consequence.
- 4
Kills rapidly and is bactericidal without needing cell division.
- 5
Lung surfactant binds and inactivates the drug, which explains its failure in pneumonia.
What it's studied for
Reported and studied effects
- Cure rates comparable to standard therapy in skin infection and bacteraemia trials
- Rapid bactericidal killing in time-kill studies
- Muscle enzyme (creatinine kinase) rises in a small percentage of patients
- Eosinophilic pneumonia reported with prolonged use
Research protocol notes
Research context onlyResearch context only - a hospital antibiotic. Licensed dosing is 4 mg per kilogram once daily for skin infection and 6 mg per kilogram once daily for bacteraemia and endocarditis, with some guidelines using 8 to 10 mg per kilogram for difficult organisms; creatinine kinase is checked weekly. Trials assess clinical success at a test-of-cure visit 7 to 14 days after the end of therapy.
These figures are described so you can understand what researchers did. They are not a dose, a schedule, or a suggestion — and they are not a substitute for a doctor.
Possible side effects and contraindications
Safety profile
Possible side effects
- Raised creatinine kinase and muscle pain, occasionally rhabdomyolysis
- Eosinophilic pneumonia with longer courses
- Diarrhoea and nausea
- Headache
- Peripheral neuropathy
- Injection-site reactions
Contraindications and cautions
- Not for community-acquired pneumonia - surfactant inactivates it
- Prior hypersensitivity
- Caution with statins and other myotoxic drugs
- Requires creatinine kinase monitoring
A side-effect list is never complete, and these are not the only situations that warrant caution. Anything unexpected, or anything you are unsure about, should be discussed with a doctor before use.
Evidence assessment
Randomised non-inferiority trials against standard therapy for skin infection and MRSA bacteraemia, with regulatory approval in the EU and US.
References
- 01Fowler et al., Daptomycin versus standard therapy for bacteremia and endocarditis caused by Staphylococcus aureus, NEJM 2006
- 02European Medicines Agency - Cubicin product information
References link to published literature, regulator pages or literature indexes. Where a link points to a search, it collects the peer-reviewed work on that molecule rather than a single study.
Related
Related peptides
Other entries in Antimicrobial.
Antimicrobial
Colistin (polymyxin E)
A last-resort lipopeptide antibiotic kept for multidrug-resistant Gram-negative infections, at the cost of kidney toxicity.
Antimicrobial
Dalbavancin
A long-acting lipoglycopeptide that treats serious skin infections with one or two doses instead of a week of infusions.
Antimicrobial
Teicoplanin
A long-acting glycopeptide antibiotic used in Europe for serious Gram-positive infections, with once-daily dosing.