Linezolid is the first of a new class of antibacterial drugs, the
oxazolidinones. It has inhibitory activity against a broad range of gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA),
glycopeptide-intermediate S. aureus (GISA), vancomycin-resistant enterococci (VRE) and
penicillin-resistant Streptococcus pneumoniae. The
drug also shows activity against certain anaerobes, including Clostridium perfringens, C. difficile, Peptostreptococcus spp. and Bacteroidesfragilis. In controlled phase III studies,
linezolid was as effective as
vancomycin in the treatment of patients with
infections caused by methicillin-resistant staphylococci and also demonstrated efficacy against
infections caused by VRE. Further phase III studies have demonstrated that
linezolid is an effective treatment for patients with
nosocomial pneumonia, for hospitalised patients with community-acquired
pneumonia, and for patients with complicated skin or
soft tissue infections (SSTIs). In these studies,
linezolid was as effective as established treatments, including
third-generation cephalosporins in patients with
pneumonia, and
oxacillin in patients with complicated SSTIs. Oral
linezolid 400 or 600mg twice daily was as effective as
clarithromycin 250mg twice daily or
cefpodoxime proxetil 200mg twice daily in the treatment of patients with uncomplicated SSTIs or community-acquired
pneumonia.
Linezolid is a generally well tolerated
drug. The most frequently reported adverse events in
linezolid recipients were diarrhoea,
headache,
nausea and
vomiting.
Thrombocytopenia was also documented in a small proportion (about 2%) of patients treated with the
drug.
CONCLUSIONS:
Linezolid has good activity against gram-positive bacteria, particularly multidrug resistant strains of S. aureus (including GISA), Enterococcus faecium and E. faecalis (including VRE). In controlled clinical trials,
linezolid was as effective as
vancomycin in eradicating
infections caused by methicillin-resistant Staphylococcus spp. and has demonstrated efficacy against
infections caused by VRE. As the level of resistance to
vancomycin increases among S. aureus and enterococci,
linezolid is poised to play an important role in the management of serious gram-positive
infections.