Daptomycin

Daptomycin has activity against the following:

• Gram-positive bacteria (broad-spectrum activity)

• Multidrug-resistant gram-positive bacteria

Daptomycin is used mainly for infections caused by

• Vancomycin- and methicillin-resistant Staphylococcus aureus

• Vancomycin-resistant enterococci

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. It is not recommended for the treatment of pulmonary airspace disease (pneumonia) because it can bind to pulmonary surfactant, reducing daptomycin’s activity in the alveolar epithelial lining fluid.

Daptomycin is contraindicated in patients who have had an allergic reaction to it.

Animal reproduction studies with daptomycin have not shown risk to the fetus, and data related to pregnancy in humans are limited to case reports. The extent to whichdaptomycin crosses the placenta is unknown. Depending on the indication and the severity of illness, using daptomycin during pregnancy may be reasonable.

Daptomycin enters breast milk, but oral availability is low; effects on breastfeeding infants are unknown.

Adverse effects of daptomycin include

• Eosinophilic pneumonia

• Myopathy

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 often reversible but seldom occurs with once-a-day dosing. Nevertheless, rhabdomyolysis has been reported, and coadministration of daptomycin with other medications associated with myopathy, such as hydroxymethylglutaryl CoA reductase inhibitors (statins), may increase risk (1).

Daptomycin is given parenterally once a 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.