chemistry

Istradefylline

Istradefylline is a chemistry 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 Istradefylline rather than just read about it. In short: Istradefylline, sold under the brand name Nourianz, is a medication used as an add-on treatment to levodopa/carbidopa in adults with Parkinson's disease (PD) experiencing "off" episodes. Istradefylline reduces "off" periods resulting from long-term treatment with the antiparkinson drug levodopa.

Key takeaways

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

Reference excerpt

Istradefylline, sold under the brand name Nourianz, is a medication used as an add-on treatment to levodopa/carbidopa in adults with Parkinson's disease (PD) experiencing "off" episodes. Istradefylline reduces "off" periods resulting from long-term treatment with the antiparkinson drug levodopa. An "off" episode is a time when a patient's medications are not working well, causing an increase in PD symptoms, such as tremor and difficulty walking. Relatively common side effects include involuntary muscle movements (dyskinesia), constipation, hallucinations, dizziness, and, much like its parent molecule caffeine, nausea and sleeplessness. The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication.

Adverse effects The adverse effects of istradefylline have only been studied in the context of treating "off" episodes in Parkinson's disease. The most common adverse effects of istradefylline in clinical trials are dyskinesia exacerbation (roughly 9% increase relative to placebo), malaise, and nasopharyngitis (common cold).

Mechanism of action Istradefylline is a selective antagonist at the adenosine A2A receptor (A2AR), but the precise mechanism by which it exerts its therapeutic effect in Parkinson's disease is unknown. However, it is known that dimers of these receptors form heterotetramers with the dimers of dopamine D2 receptors (D2R) within striatum. Adenosine acts as an endogenous A2AR agonist, but also as a negative allosteric modulator (NAM) within these tetramers towards D2Rs, thus inhibiting the D2R mediated effects of dopamine, an endogenous D2R agonist. Istradefylline is believed to bind an A2AR within an A2AR-D2R-tetramer and function as a NAM towards the other A2AR (instead of D2R), thus inhibiting the effects of adenosine and enhancing the movement (locomotion) promoting effects exerted by dopamine via D2R. However, at high istradefylline concentration, it causes locomotion depression akin to caffeine (which is a broad-spectrum adenosine receptor antagonist), and might do so by displacing adenosine, and working as a NAM towards D2R (instead of A2AR).

History It was first approved in Japan in 2013. The effectiveness of Nourianz in treating "off" episodes in patients with Parkinson's disease who are already being treated with levodopa/carbidopa was shown in four 12-week placebo-controlled clinical studies that included a total of 1,143 participants. In all four studies, people treated with Nourianz experienced a statistically significant decrease from baseline in daily "off" time compared to patients receiving a placebo. It was approved for medical use in the United States in 2019. and approval was granted to Kyowa Kirin, Inc.

Research

Wakefulness effects The wakefulness-promoting effects of non-selective adenosine receptor antagonists like caffeine appear to be mediated specifically and exclusively by antagonism of the adenosine A2A receptor. There is preliminary clinical evidence that istradefylline has wakefulness-promoting effects similarly to caffeine.

Motivational disorders Istradefylline shows pro-motivational effects in animals and has been found to reduce apathy, fatigue, and anhedonia in people with Parkinson's disease. Selective adenosine A2A receptor antagonists like istradefylline and preladenant may be useful in the treatment of motivational disorders in humans.

Other conditions In addition to Parkinson's disease, istradefylline was under development for the treatment of major depressive disorder (MDD), restless legs syndrome, and substance-related disorders. However, development for these indications was discontinued.

See also KW-6356, an adenosine A2A receptor inverse agonist intended to supersede Istradefylline.

References

External links "Istradefylline". Drug Information Portal. U.S. National Library of Medicine. Archived from the original on 27 April 2021.

Illustrations

Worked examples

Example 1 — a first encounter with Istradefylline

Start with the simplest possible case. Write down what Istradefylline claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, 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 Istradefylline 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 Istradefylline 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 Istradefylline

In research: Istradefylline appears in chemistry 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 Istradefylline 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: Istradefylline is common in secondary-school and first-year university syllabi. It links to neighbouring topics Adenosine receptor antagonists, Alkene derivatives, CYP3A4 inhibitors, so understanding it makes those chapters shorter.
In everyday life: Look for Istradefylline 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.

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How to study Istradefylline in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Istradefylline 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 Istradefylline out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Istradefylline in simple terms?

Why does Istradefylline matter?

Because it connects several chemistry 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 Istradefylline?

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 Istradefylline.