science

Quinupristin/dalfopristin

Quinupristin/dalfopristin is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Quinupristin/dalfopristin rather than just read about it. In short: 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. Quinupristin and dalfopristin are both streptogramin antibiotics, derived from pristinamycin.

Key takeaways

Quinupristin/dalfopristin belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Quinupristin/dalfopristin to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Quinupristin/dalfopristin from memory before moving on to harder problems.

Reference excerpt

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. 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 by a factor of about 100. In addition, it inhibits peptidyl transfer. Quinupristin binds to a nearby site on the 50S ribosomal subunit and prevents elongation of the polypeptide, as well as causing incomplete chains to be released.

Pharmacokinetics Clearance by the liver CYP450:3A4 inhibitor, half-life quinupristin 0.8 hours, dalfopristin 0.7 hours (with persistence of effects for 9–10 hours).

Side effects

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.

References

Illustrations

Worked examples

Example 1 — a first encounter with Quinupristin/dalfopristin

Start with the simplest possible case. Write down what Quinupristin/dalfopristin claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Quinupristin/dalfopristin before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Quinupristin/dalfopristin ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Quinupristin/dalfopristin

In research: Quinupristin/dalfopristin appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Quinupristin/dalfopristin in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Quinupristin/dalfopristin is common in secondary-school and first-year university syllabi. It links to neighbouring topics Combination antibiotics, so understanding it makes those chapters shorter.
In everyday life: Look for Quinupristin/dalfopristin outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Quinupristin/dalfopristin” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Quinupristin/dalfopristin in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Quinupristin/dalfopristin means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Quinupristin/dalfopristin out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Quinupristin/dalfopristin in simple terms?

Why does Quinupristin/dalfopristin matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Quinupristin/dalfopristin?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Quinupristin/dalfopristin.