Quinupristin
Also known as: Pristinamycin IA derivative, Quinupristin, Quinupristin/dalfopristin, RP 57669, SC-42630, Synercid
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Summary
Quinupristin is a streptogramin B cyclic depsipeptide antibiotic that is administered intravenously, usually in combination with dalfopristin (Synercid). It is prescribed for serious infections caused by susceptible Gram‑positive bacteria, including strains resistant to other agents such as methicillin‑resistant Staphylococcus aureus (MRSA) and vancomycin‑resistant Enterococcus (VRE). The drug targets bacterial protein synthesis and is used when other options are limited.
Mechanism of Action
Quinupristin binds to the 50S ribosomal subunit of bacteria, occupying a site distinct from that of streptogramin A (dalfopristin). This binding interferes with the elongation step of protein synthesis, halting peptide chain formation. When combined with dalfopristin, the two agents act synergistically: dalfopristin alters the ribosome to enhance quinupristin binding, resulting in a bactericidal effect against susceptible Gram‑positive organisms.
What the Research Shows
A 2024 meta‑analysis of 74 studies reported that resistance to quinupristin‑dalfopristin among clinical Enterococcus faecalis isolates has risen over time, indicating emerging challenges for its continued efficacy. A 2012 review highlighted quinupristin‑dalfopristin as an intracellularly active agent capable of penetrating bacterial biofilms, suggesting potential utility in chronic adenotonsillar disease where biofilm‑embedded pathogens persist. A 2022 molecular review listed streptogramin B resistance mechanisms—including target modification, efflux pumps, and enzymatic inactivation—demonstrating that Staphylococcus aureus can acquire resistance to quinupristin. Collectively, these sources portray a drug with proven activity but facing increasing resistance in key pathogens.
Reported Benefits
Quinupristin, especially when paired with dalfopristin, offers a bactericidal option against difficult‑to‑treat Gram‑positive infections, including MRSA and VRE, where many other antibiotics fail. Its ability to act synergistically enhances potency, and reviews note its capacity to penetrate intracellular compartments and biofilms, potentially addressing persistent infections such as those in adenotonsillar disease. These properties make it a valuable therapeutic alternative in settings of limited antimicrobial options.
Limitations of the Evidence
Evidence indicates a growing prevalence of resistance to quinupristin‑dalfopristin in Enterococcus faecalis and Staphylococcus aureus, undermining its reliability. The literature consists mainly of systematic reviews and mechanistic studies rather than large‑scale clinical trials, limiting definitive efficacy data for newer indications. Resistance mechanisms such as ribosomal target alteration and efflux further restrict its spectrum. Consequently, its clinical utility may diminish without vigilant susceptibility monitoring.
Safety Considerations
The cited abstracts do not provide specific adverse‑event data for quinupristin. Consequently, safety information is limited to the acknowledgement that resistance development is a concern, which may necessitate careful microbiological monitoring. Clinicians should remain alert for potential drug‑related toxicities known from other sources and consider patient‑specific factors before use.
How It Is Administered
Quinupristin is supplied for intravenous infusion, typically as part of the fixed‑dose combination with dalfopristin (Synercid). The formulation is intended for hospital administration under professional supervision; dosing regimens are not detailed in the available literature.
Routes of Administration
Goals & Uses
- S. aureus bacteremia (including MRSA)Infectious DiseaseHigh
- Complicated skin and skin structure infections (cSSSI)AntibacterialHigh
- Nosocomial pneumonia due to Gram-positive organismsAntimicrobial / Infectious DiseaseLow
- Treatment of vancomycin-resistant Enterococcus faecium (VREF) infectionsAntimicrobial / Infectious DiseaseHigh
- Complicated skin and skin‑structure infectionsAntibacterialHigh
- MRSA infections (off-label)Antimicrobial / Infectious DiseaseModerate
Contraindications
- Concurrent use of drugs metabolized by CYP3A4 with narrow therapeutic indexDrug InteractionHigh
- Hypersensitivity to quinupristin, dalfopristin, or other streptograminsAllergyHigh
- Severe hepatic impairmentOrganModerateLiver function concerns
- Hypersensitivity to streptograminsAllergyHigh
Adverse Effects
- Elevated liver enzymes (AST/ALT)HepatotoxicityUncommon
- Infusion site reactions (pain, inflammation, thrombophlebitis)LocalCommon
- Nausea/vomitingGastrointestinalCommon
- Nausea and vomitingGastrointestinalCommon
- Rash/pruritusDermatologicCommon
- Arthralgia and myalgiaMusculoskeletalCommon
- Elevated hepatic transaminases (AST/ALT)HepaticUncommon
- QT prolongationCardiovascularRareExtended QT interval on ECG
- DiarrheaGastrointestinalCommonLoose or frequent stools
- HyperbilirubinemiaHepaticCommon
Drug Interactions
- CyclosporineHigh
- QT-prolonging agents (e.g., cisapride, terfenadine)High
- HMG-CoA reductase inhibitors (statins metabolized by CYP3A4)Moderate
- TacrolimusHigh
- DalfopristinLow
- Cytochrome P450 inhibitors (e.g., azole antifungals)Moderate
Population Constraints
- PregnancyReproductive SafetyRelative
- Hepatic impairmentOrgan FunctionRelative
- Pediatric patientsAgeRelative
- Patients on multiple CYP3A4-metabolized drugsPolypharmacyRelative
- Pregnancy (Category B)PregnancyRelative
- Pediatric patients <12 yearsAgeAbsolute
Regulatory Status
- European UnionApprovedApproved: Complicated skin and skin‑structure infections, S. aureus bacteremiaApproved under same combination product
- United StatesApprovedApproved: Complicated skin and skin‑structure infections, S. aureus bacteremiaApproved as dalfopristin/quinupristin (Synercid) IV infusion
- United KingdomApprovedApproved: Vancomycin-resistant Enterococcus faecium infections, Complicated skin and skin structure infectionsPreviously approved under EMA authorization; post-Brexit status follows UK licensing. Niche use in resistant Gram-positive infections.
Approved in the US (1999) and EU for skin/soft‑tissue infections and S. aureus bacteremia; not indicated for pediatric use <12 y; caution in hepatic or renal impairment.
Evidence & Sources
- Journal ArticleHighGuan L, et al.2024-01-01T00:00:00.000000Z
- Journal ArticleModerateZautner AE2012-01-01T00:00:00.000000Z
- Journal ArticleModerateMlynarczyk-Bonikowska B, et al.2022-01-01T00:00:00.000000Z
Frequently Asked Questions
What types of infections is quinupristin used to treat?
Quinupristin, in combination with dalfopristin, is employed for serious Gram‑positive infections, especially those caused by resistant organisms such as MRSA and VRE, when other antibiotics are ineffective.
Why is resistance to quinupristin a growing problem?
Recent meta‑analyses show increasing resistance rates in Enterococcus faecalis, and molecular studies describe mechanisms like ribosomal modification and efflux that allow Staphylococcus aureus to evade the drug’s action.
Can quinupristin reach bacteria inside biofilms or cells?
A 2012 review reports that quinupristin‑dalfopristin penetrates intracellular compartments and biofilm matrices, suggesting it may help eradicate persistent bacterial reservoirs in conditions such as chronic adenotonsillar disease.
How is quinupristin administered?
The drug is delivered intravenously, usually as the fixed‑dose combination Synercid, and is administered in a clinical setting under medical supervision.
What safety monitoring is recommended?
While specific adverse‑event data are lacking in the cited literature, clinicians should monitor for emerging resistance and follow standard safety protocols for intravenous antibiotics, adjusting therapy based on susceptibility testing.
What is Quinupristin?
Quinupristin is a streptogramin B cyclic depsipeptide antibiotic that is administered intravenously, usually in combination with dalfopristin (Synercid). It is prescribed for serious infections caused by susceptible Gram‑positive bacteria, including strains resistant to other agents such as methicillin‑resistant Staphylococcus aureus (MRSA) and vancomycin‑resistant Enterococcus (VRE). The drug targets bacterial protein synthesis and is used when other options are limited.
What is Quinupristin used for?
Quinupristin is educationally associated with: S. aureus bacteremia (including MRSA), Complicated skin and skin structure infections (cSSSI), Nosocomial pneumonia due to Gram-positive organisms, Treatment of vancomycin-resistant Enterococcus faecium (VREF) infections, Complicated skin and skin‑structure infections, MRSA infections (off-label). Educational only — not medical advice.
How is Quinupristin administered?
Recorded routes of administration: Intravenous.
What are the potential side effects of Quinupristin?
Reported adverse effects include: Elevated liver enzymes (AST/ALT), Infusion site reactions (pain, inflammation, thrombophlebitis), Nausea/vomiting, Nausea and vomiting, Rash/pruritus, Arthralgia and myalgia, Elevated hepatic transaminases (AST/ALT), QT prolongation, Diarrhea, Hyperbilirubinemia. This list is not exhaustive — consult a qualified clinician.
Who should avoid Quinupristin?
Recorded contraindications: Concurrent use of drugs metabolized by CYP3A4 with narrow therapeutic index, Hypersensitivity to quinupristin, dalfopristin, or other streptogramins, Severe hepatic impairment, Hypersensitivity to streptogramins. Consult a qualified clinician before use.