In rejoinder to the emergence of r...

In rejoinder to the emergence of resistant bacteria, efforts are being made to make known antimicrobial agents that are active against these resistant organisms. The oxazolidinones are a recently made known family of totally synthetic antimicrobials for which there are no preexisting resistance gene in bacteria. Moellering reviewed the activity and clinical use of linezolid, the first oxazolidinone approved for use in the United States.

Linezolid set to work s its antimicrobial effect by a unique mechanism of action that proceeds in inhibition of bacterial ribosome assembly. Because no other known antimicrobial agent inhibits this proces there is no cross-resistance with other antibiotics. All major pathogenic gram-positive bacteria are sensitive to linezolid in vitro. The medicine demonstrates in vitro activity against major strains of Neisseria and borderline activity against Haemophilus influenzae, nevertheless it is inactive against Enterobacteriaceae and Pseudomonas species. Although linezolid has demonstrated activity against atypical organisms, including Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydia pneumoniae, more data are penuryed on its effectiveness against these organisms in vivo. The reply to combinations of linezolid with other antibiotics appears to be additive or neutral, and rarely antagonistic or synergistic. evolution of resistance is rare moreover has occurred in patients with indwelling prostheses who received long-term linezolid therapy.

praiseed dosing is 400 to 600 mg twice daily, administered orally or intravenously. No dosing adjustment is destitutioned for weight, gender, or time of administration in relation to meals. Linezolid is metabolized according to oxidation, and its pharmacokinetic characteristics are not affected at renal or hepatic dysfunction. medicine accumulation has been noted in patients with impaired renal function, unless clinical significance has not been determined. Serum put drugs into concentrations are decreased after hemodialysis; available data hint that postdialysis supplemental dosing is necessary.

Linezolid is commonly approved by the U.S. bread and Drug Administration for use in treating, among others, the following infections: vancomycin-resistant Enterococcus faecium infections, community-acquired or nosocomial pneumonia caused by the agency of penicillin-susceptible Streptococcus pneumoniae or Staphylococcus aureus, and skin infections caused through S. aureus or Streptococcus pyogene Because of lack of activity against H influenzae, linezolid should not be considered a first-line remedy for community-acquired pneumonia. Studies are being administrationed to evaluate the effectiveness of linezolid in patients with endocarditis, osteomyelitis, and meningitis.

Adverse general intents of linezolid are rare, unless reversible myelosuppression, notably thrombocytopenia, has been noted. Weekly without fault [i]or[/i] blemish [i]or[/i] flaw blood counts are recommended during therapy, especially in patients receiving linezolid for more than couple weeks.

The author bring to an ends that linezolid is useful against almost all of the important gram-positive organisms. It is effective in skin, respiratory, and systemic infections caused by way of susceptible organisms, but it should not be considered a first- or second-line therapy for community-acquired respiratory infections. Compared with vancomycin, linezolid may come in shorter hospital stays for patients with known or suspected methicillin-resistant staphylococcal infections. However, the sumptuousness per dose for linezolid is relatively high: approximately $53 for single in kind 600-mg oral dose and $72 for a 600-mg intravenous dosing vial. No clinical trials have compared the efficacy of linezolid to that of quinupristin-dalfopristin (another intravenously administered antimicrobial that is used to treat multiresistant gram-positive infections).

Moellering RC Jr Linezolid: the first oxazolidinone antimicrobial. Ann Intern M January 21 2003;138:135-42

COPYRIGHT 2003 American Academy of Family Physicians

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