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Antibiotics
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Linezolid
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Ciprofloxacin

Linezolid (Zyvox)


  • Generic name: Linezolid
  • Trade names: Zyvox, Zyvoxid, Zyvoxam
  • Pharmacologic category: Oxazolidinone antibiotic
  • FDA approved: April 18, 2000
  • Pregnancy risk factor: C

Medical uses

Linezolid (Zyvox) is a member of a new class of antibiotics called oxazolidinones with a unique mechanism of action. Linezolid fights many resistant gram-positive cocci, such as vancomycin-resistant Enterococcus faecium (VRE) and methicillin-resistant S. aureus (MRSA).

Linezolid is meant for life-threatening or complicated infections associated with multiple resistances. It does not

The most frequently reported side effects with Linezolid are headache, nausea, diarrhea, and vomiting. The most important laboratory test change is a decrease in platelet counts.

Linezolid should be used very judiciously so as to guard its antibacterial utility.

Linezolid (Zyvox) vs. Vancomycin

The research supports linezolid as the more efficient choice for complicated skin and soft tissue infections due to suspected or proven MRSA.

In the study4 the cure rates were significantly higher among linezolid patients compared with vancomycin patients (91.7% vs. 86.0%). The most significant difference in cure rates appeared in the MRSA population - 94.2% in the linezolid group vs. 83.7% in the vancomycin group. In addition, the overall mean length of hospital stay for linezolid patients was approximately 2-3 days less than that of the vancomycin patients.

Linezolid has been recognized as having a theoretical advantage in treating pneumonia, as it achieves higher lung epithelial concentrations than vancomycin.

Linezolid is a particularly attractive antibiotic compared to vancomycin in patients who have impaired renal function, poor intravenous access, require outpatient therapy, or who have been unable to tolerate glycopeptides.

Pharmacological characteristics

  • Absorption: rapid and complete absorption from gastrointestinal tract.
  • Metabolism: Partial hepatic metabolism, metabolized in the liver, by oxidation of the morpholine ring, without involvement of the cytochrome P450 system.
  • Elimination half-life: Children 1 week to 11 years: 1.5-3 hours; Adults: 4-5 hours.
  • Excretion: Elimination occurs through nonrenal (65%), renal (30%), and fecal (5%) mechanisms.

Benefits

  • High cure rates for various types of infections.
  • Effective and promising new antibacterial drug for several serious antibiotic-resistant infections, including difficult-to-treat organisms MRSA and VRE.
  • When used for short periods, linezolid is a relatively safe.
  • Linezolid does not damage kidney or liver function.
  • Linezolid is virtually 100% absorbed if taken by mouth, so oral dosing is essentially equivalent to parenteral dosing. Excellent bioavailability allows early change from intravenous to oral therapy.
  • Minimal potential for resistance. Cross-resistance does not develop between linezolid and other antibiotics.

Concerns

  • Linezolid is new and quite expensive antibiotic.
  • Risk of hematological disturbances, including anemia, thrombocytopenia, and myelosuppression. Linezolid can cause bone marrow suppression and low platelet counts, particularly when used for more than two weeks. Thrombocytopenia (low platelet count), uncommon with short-term use for 14 days or fewer, but occurs much more frequently in patients who receive longer courses or who have renal impairment.
  • Prolonged use of linezolid may cause damage to the peripheral nervous system (peripheral neuropathy) and optic nerve (optic neuropathy)2.
  • Lactic acidosis, a potentially life-threatening buildup of lactic acid in the body, is rare but serious side effect that may occur with linezolid due to its mitochondrial toxicity.
  • Potential for drug interactions. Linezolid is a weak MAO inhibitor (nonselective).

Unlabeled uses

  • Infective endocarditis
  • Bone and joint infections
  • Central nervous system infections (including meningitis)
  • Extensively drug-resistant tuberculosis1

Mode of action

Linezolid stops the growth of bacteria by disrupting their production of proteins. Although many antimicrobials work this way, the exact mechanism of action of linezolid appears to be unique to the oxazolidinone class. Linezolid works on the first step of protein synthesis, initiation, unlike most other protein synthesis inhibitors, which inhibit elongation.

Bacterial resistance to linezolid has remained very low since it was first detected in 1999, although it may be increasing.

Reviews

References

  • 1. Park IN, Hong SB, Oh YM, Kim MN, Lim CM, Lee SD, Koh Y, Kim WS, Kim DS, Kim WD, Shim TS. Efficacy and tolerability of linezolid in patients with intractable multidrug-resistant tuberculosis. J Antimicrob Chemother. 2006 Sep;58(3):701-4.
  • 2. Bressler AM, Zimmer SM, Gilmore JL, Somani J. Peripheral neuropathy associated with prolonged use of linezolid. Lancet Infect Dis. 2004 Aug;4
  • 3. De Vriese AS, Coster RV, Smet J, Seneca S, Lovering A, Van Haute LL, Vanopdenbosch LJ, Martin JJ, Groote CC, Vandecasteele S, Boelaert JR. Linezolid-induced inhibition of mitochondrial protein synthesis. Clin Infect Dis. 2006 Apr 15;42(8):1111-7.
  • 4. Weigelt J, Itani K, Stevens D, Lau W, Dryden M, Knirsch C; Linezolid CSSTI Study Group. Linezolid versus vancomycin in treatment of complicated skin and soft tissue infections. Antimicrob Agents Chemother. 2005 Jun;49(6):2260-6. PubMed

By HealthyStock Research Group, September 2009
Medical resources reviewed: August 2018

Interesting Zyvox facts

Zyvox Linezolid

  • The oxazolidinones have a novel mechanism of action in that they inhibit initiation complex formation in bacterial protein synthesis.
  • Zyvox is the first FDA approved antibiotic of the newest oxazolidinone class. Its exact mechanism of action is not known.
  • Its activity is bacteriostatic against some species (e.g., enterococci) and bactericidal against others (e.g., pneumococci).

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