Quinupristin/dalfopristin
Combination drug
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Quinupristin/dalfopristin, or quinupristin-dalfopristin, (pronunciation: kwi NYOO pris tin / dal FOE pris tin) (trade name Synercid) is a combination of two antibiotics used to treat infections caused by staphylococci and by vancomycin-resistant Enterococcus faecium.
category
- AU: B3
- B (U.S.)
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 Quinupristin (top) and dalfopristin (bottom) | |
| Combination of | |
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| Quinupristin | Streptogramin antibiotic |
| Dalfopristin | Streptogramin antibiotic |
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| Routes of administration | IV |
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Quinupristin and dalfopristin are both streptogramin antibiotics, derived from pristinamycin. Quinupristin is derived from pristinamycin IA; dalfopristin from pristinamycin IIA. They are combined in a weight-to-weight ratio of 30% quinupristin to 70% dalfopristin. Discontinued 2022, there are no other manufacturers of this medication.
Administration
Intravenous, usually 7.5 mg/kg every 8 hours (infections/life threatening VRSA); every 12 hours (skin infections). No renal dosing adjustments, hepatic dosing adjustments are not defined, consider reducing dose.
Mechanism of action
Quinupristin and dalfopristin are protein synthesis inhibitors in a synergistic manner. While each of the two is only a bacteriostatic agent, the combination shows bactericidal activity.
- Dalfopristin binds to the 23S portion of the 50S ribosomal subunit, and changes the conformation of it, enhancing the binding of quinupristin[1] by a factor of about 100. In addition, it inhibits peptidyl transfer.[1]
- Quinupristin binds to a nearby site on the 50S ribosomal subunit and prevents elongation of the polypeptide,[1] as well as causing incomplete chains to be released.[1]
Pharmacokinetics
Side effects
[2]
Serious:
- C.diff-associated diarrhea
- superinfection
- anaphylactoid reactions
- angioedema
Common:
- Joint aches (arthralgia) or muscle aches (myalgia)
- Nausea, diarrhea (C. diff associated) or vomiting
- Rash or itching
- Headache
- Hyperbilirubinemia
- Anemia
- Thrombophlebitis
Drug interactions
The drug inhibits P450 and enhances the effects of terfenadine, astemizole, indinavir, midazolam, calcium channel blockers, warfarin, cisapride and ciclosporin.