Daptomycin: the first approved lipopeptide antimicrobial.
OBJECTIVE
To review the literature concerning the first Food and Drug Administration-approved lipopeptide antimicrobial, daptomycin.


METHODS
A PUBMED search was conducted to identify pertinent English-language journal articles between 1985 and November 2003, and additional references were obtained from the bibliographies of these articles. Abstracts from the Interscience Conference on Antimicrobial Agents and Chemotherapy meetings from 1985 through 2003 also were reviewed.


METHODS
All studies evaluating any aspect of daptomycin.


RESULTS
Daptomycin is a semisynthetic lipopeptide, the first such antimicrobial agent to reach the marketplace. Its mechanism of action differs from that of the related agent vancomycin in that much of its effect is not because of inhibition of peptidoglycan biosynthesis, but instead is a result of alterations in cell-membrane electrical charge and transport. It exhibits a broad spectrum of activity against gram-positive aerobes and anaerobes, including methicillin-, penicillin-, aminoglycoside-, and vancomycin-resistant strains. In subjects with normal renal function, the terminal disposition half-life is about 7 to 10 hours. It is principally eliminated as unchanged drug in the urine. Available clinical trial data demonstrate efficacy in complicated skin and skin-structure infections resulting from susceptible gram-positive pathogens, but not in pneumonia. The principal adverse event of concern, although rare, is myotoxicity, manifested by muscle pain and/or weakness and elevated serum creatine phosphokinase (CPK) concentrations. The approved dosage regimen is 4 mg/kg intravenously over 30 minutes once daily for 7 days to 14 days. Studies are underway evaluating doses of up to 8 mg/kg once daily.


CONCLUSIONS
Daptomycin, the first lipopeptide antimicrobial to be marketed, exhibits activity against multiresistant gram-positive pathogens, including linezolid- and quinupristindalfopristin-resistant strains. As such, it is a potentially valuable agent to treat infections resulting from such pathogens. To preserve its utility, it should not be used indiscriminately for infections resulting from pathogens sensitive to other antimicrobials. It is probably best used with restricted access and used only for multiresistant gram-positive pathogens where alternative agents cannot be employed. If used, careful monitoring for the signs and symptoms of myotoxicity, including obtaining weekly serum CPK levels, is mandatory. In addition, bacterial sensitivities to this agent should be prospectively monitored by national antimicrobial surveillance programs like SENTRY, TRUST, and LIBRA.
Guay
David R P
DR
Institute for the Study of Geriatric Pharmacotherapy, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA. guayxoo1@umn.edu