IDStewardship

Quinupristin-dalfopristin (Synercid)

[Quinupristin-dalfopristin photo]

KEY POINTS

  • Quinupristin-dalfopristin (Synercid) is a streptogramin antimicrobial agent that interferes with bacterial protein synthesis in susceptible isolates through interaction with the 50S bacterial ribosomal subunit
    • Dalfopristin inhibits the early phase of protein synthesis
    • Quinupristin inhibits the late phase of protein synthesis
    • Exhibits bacteriostatic killing
  • Is rarely used in clinical practice due to substantial toxicities and alternative therapies for methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE)
    • When it is used, the indication is typically for a complicated case involving infection due to vancomycin-resistant Enterococcus faecium
  • Has activity versus numerous drug-resistant Gram positive bacteria
    • Has activity versus Enterococcus faecium, including some vancomycin-resistant isolates (i.e., VRE)
    • Nearly all Enterococcus faecalis isolates are resistant to quinupristin-dalfopristin
    • Has activity against some MRSA isolates
  • Common dose in adults is 7.5 mg/kg every 8-12 hours
    • No adjustment for renal function
      • Mostly excreted in feces
    • Adjustments may be needed for hepatic function
  • Some serious toxicities of concern that occurs at a disturbingly high rate include: arthralgia and myalgias, phlebitis, and hyperbilirubinemia
  • Administration of quinupristin-dalfopristin can be complicated
    • Typical infusion time is 1 hour and volume of 250mL D5W
    • May require larger fluid volume to reduce phlebitis
    • Is preferable to infuse via a central line to limit venous irritation
    • Can precipitate if mixed with normal saline or heparin, so need to flush the line with D5W before and after doses
    • See package insert for more details on this issue
  • Not widely available (if at all) on the US market

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