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Daptomycin is a cyclic lipopeptide antibiotic that has a unique mechanism of action. It binds to the bacterial cell membranes, causing rapid depolarization of the membrane due to K efflux and associated disruption of DNA, RNA, and protein synthesis; the result is rapid concentration-dependent bacterial death.
Indications
Daptomycin has activity against the following:
Daptomycin is used mainly for infections caused by
However, methicillin-resistant S. aureus and vancomycin-resistant enterococci may become resistant during daptomycin therapy, resulting in relapsing or persistent infection.
Daptomycin is inferior to ceftriaxone for pneumonia, presumably because daptomycin can bind to pulmonary surfactant, reducing daptomycin's activity in the alveolar epithelial lining fluid.
Contraindications
Daptomycin is contraindicated in patients who have had an allergic reaction to it.
Use During Pregnancy and Breastfeeding
Daptomycin is in pregnancy category B (animal studies show no risk and human evidence is incomplete).
Whether daptomycin enters breast milk and is safe to use during breastfeeding is unknown.
Adverse Effects
Adverse effects include
Chronic use may cause reversible organizing pneumonia with eosinophilic pulmonary infiltrates, presumably because daptomycin binds to pulmonary surfactant and thus accumulates in the alveolar spaces.
Skeletal myopathy due to daptomycin is reversible but seldom occurs with once/day dosing.
Dosing Considerations
Daptomycin is given parenterally once/day. Over 90% is bound to serum protein. Dosing is adjusted for renal failure. Because daptomycin can cause reversible skeletal myopathy, patients should be monitored for muscle pain or weakness, and serum creatine kinase levels should be checked weekly.
Last full review/revision July 2009 by Matthew E. Levison, MD
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