Linezolid.

Linezolid is an oxazolidinone antibacterial agent that acts by inhibiting the initiation of bacterial protein synthesis. Cross-resistance between linezolid and other inhibitors of protein synthesis has not been demonstrated. Linezolid has a wide spectrum of activity against gram-positive organisms including methicillin-resistant staphylococci, penicillin-resistant pneumococci and vancomycin-resistant Enterococcus faecalis and E. faecium. Anerobes such as Clostridium spp., Peptostreptococcus spp. and Prevotella spp. are also susceptible to linezolid. Linezolid is bacteriostatic against most susceptible organisms but displays bactericidal activity against some strains of pneumococci, Bacteroides fragilis and C. perfringens. In clinical trials involving hospitalised patients with skin/soft tissue infections (predominantly S. aureus), intravenous/oral linezolid (up to 1250 mg mg/day) produced clinical success in >83% of individuals. In patients with community-acquired pneumonia, success rates were >94%. Preliminary clinical data also indicate that twice daily intravenous/oral linezolid 600 mg is as effective as intravenous vancomycin 1 g in the treatment of patients with hospital-acquired pneumonia and in those with infections caused by methicillin-resistant staphylococci. Moreover, linezolid 600 mg twice daily produced >85% clinical/microbiological cure in vancomycin-resistant enterococcal infections. Linezolid is generally well tolerated and gastrointestinal disturbances are the most commonly occurring adverse events. No clinical evidence of adverse reactions as a result of monoamine oxidase inhibition has been reported.