- Overview
- Linezolid (Zyvox) should
be used only for well-documented, serious vancomycin (Vancocin)
resistant enterococcal infections
- New
antibiotic class: oxazolidinones
- Management
for infections caused by:
- Vancomycin
(Vancocin)-resistant Enterococcus faecium
- Nosocomial
& community-acquired Staphylococcus aureus
pneumonia
- Nosocomial
& community acquired danazol (Donocrine)-susceptible
Streptococcus pneumoniae
- Skin & skin-structure infections
- Two formulations FDA approved for treatment of
vancomycin (Vancocin)-resistant enterococci:
- linezolid (Zyvox)--oral & parenteral use
 quinupristin/dalfopristin
(Synercid) -- parenteral use only
- Antibacterial
characteristics
- Inhibits
bacterial ribosomal-mediated protein synthesis
- Bacteria
static against streptococci
- Activity
profile:
- Linezolid (Zyvox): effective against both E.
faecium and Enterococcus faecalis {quinupristin/dalfopristin
(Synercid): active against vancomycin (Vancocin)-resistant
E. faecium but not Enterococcus faecalis}
- Linezolid (Zyvox):
- Active against staphylococci, including methicillin (Staphcillin)
resistance Staphylococcus aureus &
methicillin (Staphcillin) resistance Staphylococcus
epidermidis
- Active against
penicillin-resistant pneumococci & Staphylococcus
aureus with intermediate susceptibility vancomycin (Vancocin)
- No clinical useful gram-negative activity
- Pharmacokinetics:
- Following oral administration:
rapid/complete absorption from gastrointestinal tract
- Partial hepatic metabolism
- Urinary excretion
- Side/Adverse Effects
- Well-tolerated
- Most-common
adverse effects: gastrointestinal (nausea, diarrhea, vomiting)
- With prolonged use: reversible
thrombocytopenia
- For treatment > 2 weeks, platelet
count monitoring is recommended
- Linezolid (Zyvox) oral suspension contains
phenylalanine, contraindicated in patients with
phenylketonuria
- Drug-Drug
Interactions
- Linezolid (Zyvox)-weak MAO inhibitor
(nonselective)
- Patients should avoid tyramine-rich
foods
- Cautious use with linezolid (Zyvox) in
combination with:
- pseudoephedrine
- phenylpropanolamine
- serotonin selective reuptake
inhibitors (SSRIs)
- possibly other antidepressants
- No effect on cytochrome P450 enzyme
metabolizing system
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