Skip to content

Istradefylline

  • Prescription medicine
  • Prescription only
  • Identity checked
  • Sources last checked 2026-09-04

This page shows what was measured, who it was measured in, and what that does not settle.

What Istradefylline does in the body

NOURIANZ is indicated as adjunctive treatment to levodopa/carbidopa in adult patients with Parkinson's disease (PD) experiencing "off" episodes.

From the FDA-approved label: The precise mechanism by which istradefylline exerts its therapeutic effect in Parkinson’s disease is unknown. In in vitro studies and in in vivo animal studies, istradefylline was demonstrated to be an adenosine A 2A receptor antagonist.

Why people take it. NOURIANZ is indicated as adjunctive treatment to levodopa/carbidopa in adult patients with Parkinson's disease (PD) experiencing "off" episodes.

What happened in people

RNAWiki has not yet published a reviewed conclusion for this use.

A fixed RNAWiki sentence

Where this came from

Wording RNAWiki always uses, not a finding about this substance.

No reviewed claim names a result for any goal on this record.

No source is stored against this line.

The limit that matters most

Not recorded.

Where it acts
Not recorded.
Kind of result
No result is published, so no kind of result applies yet
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.

What the registries record it as

  • The substance registry classes this as chemical.

    FDA substance registry · 2GZ0LIK7T4 · read 2026-08-29

  • Its recorded molecular formula is C20H24N4O4, weighing 384.43.

    US prescribing information · a7d008cb-b273-4049-a5d2-9c6902910d58 · read 2026-08-30

Where each sentence above came from

The use the label states, quoted from it. No plain-language version of this sentence has been written.

The use the label states, quoted from it. It is written for a clinician, not for a reader without medical training.

No statement of the main limit is recorded.

The four opening statements run to 89 words.

Words this page uses

Four words worth knowing first

Chosen from what this page shows, with each one explained before the word it depends on.

Biomarker

A biomarker is a number from a test that stands in for something about health.

A picture of it, and where the picture fails

A biomarker is like a fuel gauge.

Where that stops being true. A gauge is wired to the tank. Many biomarkers are only loosely tied to health.

What people get wrong. A better number is read as a better life. Several medicines improved a number and helped nobody.

A measurable indicator used as a substitute for a clinical outcome of interest.

Placebo

A placebo is a dummy treatment given so the real one can be compared with it.

A picture of it, and where the picture fails

A placebo is like a blank control in an experiment.

Where that stops being true. A blank does nothing. People given a placebo often do get better.

What people get wrong. A placebo effect is read as imaginary. The improvement is measured and real.

An inactive intervention matched in appearance to the test intervention, used to control for non-specific effects.

Comparator

A comparator is whatever the treatment was measured against.

A picture of it, and where the picture fails

It is like the other runner in a race.

Where that stops being true. A race has one winner. A study can show both arms improved.

What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.

The control condition against which the experimental intervention is assessed.

What happened in peopleRead from sources, not yet reviewed

What happened in people

Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.

Safety

The study did not show it

Who was studied
NCT00199368
How many people
1100
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot

Change From Baseline in the Total Hours of Awake Time/Day Spent in the OFF State at Week 12

The study did not show it

Who was studied
NCT01968031
How many people
613
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot

To establish the efficacy of 10, 20 and 40 mg/d istradefylline for reducing the percentage of OFF time in patients with advanced Parkinson's disease (PD) treated with levodopa/carbidopa.

The study did not show it

Who was studied
NCT00199420
How many people
580
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot

Safety as Measured by Adverse Events

The study did not show it

Who was studied
NCT00199381
How many people
504
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot

OFF time assessed by patient diaries at endpoint.

The study did not show it

Who was studied
NCT00199394
How many people
405
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot

Reducing the mean total hours of awake time per day spent in the OFF state

The study did not show it

Who was studied
NCT00955526
How many people
373
Study design
Phase 3
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Result not recorded on this page
Repeated elsewhere
Unreplicated

What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.

The limits of this study, and where it came from

Main limit. No limitation is recorded for this study.

How far it carries. This study is recorded from the curated record, not from the registry match.

Form and route. Oral

Interval reported. Not recorded in this summary

Written into the record, not signed off as a reviewed claim.

  • openFDA Drugs@FDA · a recorded source, not a stored snapshot
  • openFDA NDC Directory · a recorded source, not a stored snapshot
  • openFDA SPL label · a recorded source, not a stored snapshot
  • PubChem PUG-REST · a recorded source, not a stored snapshot
What we know
RNAWiki holds 6 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.

What is missing or unclearRead from sources, not yet reviewed

Were people like you studied?

RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.

Who was studied

People similar to this profile were included.

  • NOURIANZ is indicated as adjunctive treatment to levodopa/carbidopa in adult patients with Parkinson's disease (PD) experiencing "off" episodes. NOURIANZ is an adenosine receptor antagonist indicated as adjunctive treatment to levodopa/carbidopa in adult patients with Parkinson's disease (PD) experiencing "off" episodes ( 1 ).

Who is missing from the studies

  • Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.

What the label states about particular groups

  • On pediatric, the label states: “Safety and effectiveness in pediatric patients have not been established.”

    US prescribing information · a7d008cb-b273-4049-a5d2-9c6902910d58 · read 2026-08-30

  • On older people, the label states: “No adjustment of NOURIANZ dosage is recommended on the basis of age.”

    US prescribing information · a7d008cb-b273-4049-a5d2-9c6902910d58 · read 2026-08-30

  • On people who are pregnant, the label states: “Risk Summary There are no adequate data on the developmental risk associated with the use of NOURIANZ in pregnant women.”

    US prescribing information · a7d008cb-b273-4049-a5d2-9c6902910d58 · read 2026-08-30

  • On people who are breastfeeding, the label states: “Risk Summary There are no data on the presence of istradefylline in human milk, the effects of istradefylline on the breastfed infant, or the effects of istradefylline on milk production.”

    US prescribing information · a7d008cb-b273-4049-a5d2-9c6902910d58 · read 2026-08-30

  • On people with reduced liver function, the label states: “No adjustment of NOURIANZ dosage is needed in patients with mild hepatic impairment (Child-Pugh Class A).”

    US prescribing information · a7d008cb-b273-4049-a5d2-9c6902910d58 · read 2026-08-30

  • On people with reduced kidney function, the label states: “No adjustment of NOURIANZ dosage is needed in patients with mild renal impairment (estimated creatinine clearance (CrCL) by Cockcroft-Gault equation: 60-89 mL/min), moderate renal impairment (CrCL 30-59 mL/min), or severe renal impairment (CrCL 15-29 mL/min).”

    US prescribing information · a7d008cb-b273-4049-a5d2-9c6902910d58 · read 2026-08-30

Where the result stopped carrying

  • This is a scope explorer, not a diagnosis engine.
  • It shows who was studied so you can see whether people similar to you were included.

RNAWiki cannot tell whether a study fits you. It can show who was in it.

What it would be like to takeRead from sources, not yet reviewed

Why it might seem to do nothing

A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.

It was studied in different people

The people in the studies were not much like the reader.

On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.

The evidence may simply be wrong

Small early studies often do not hold up.

On this record: RNAWiki has not yet published a reviewed conclusion for this use.

Other reasons RNAWiki checked and found nothing for (11)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.

None of these is a reason to take more. Taking more is not a step this page ever suggests.

What it would be like to takeRead from sources, not yet reviewed

What taking it involves

The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.

How it is supplied

Prescription only

Quoted from a source

Where this came from

Copied from a source RNAWiki stored, with the source named.

Read from the recorded approval status.

No source is stored against this line.

Form and route

Oral

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

The form and route recorded on this substance.

No source is stored against this line.

Who oversees it

RNAWiki has not recorded a supervision or regulatory status for this substance.

Quoted from a source

Where this came from

Copied from a source RNAWiki stored, with the source named.

No register row and no identity class settled the question.

No source is stored against this line.

What is in the pack

Sold as tablet, tablet, film coated, given by the oral route.

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

Recorded notes on how this is sold and what that means for what is in the pack.

No source is stored against this line.

Where it is registered

Regulatory records are listed in the technical disclosure at the foot of this page.

Counted from records

Where this came from

A count of rows RNAWiki holds. It describes our records, not your body.

Register entries are stored per jurisdiction and shown with their dates.

No source is stored against this line.

Why people stop

Not recorded.

Nothing recorded

Where this came from

RNAWiki holds nothing here and says so rather than guessing.

No record of why people stopped taking it is stored for this substance.

No source is stored against this line.

What it would be like to takeNothing found in the sources checked

What can go wrong

Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.

Nothing found in the sources checked

No harm is recorded against this substance in the sources RNAWiki checked. Finding nothing is not the same as showing there is nothing.

The sources listed were searched and held nothing. That is not the same as nothing existing.

Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.

Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.

What is missing or unclearRead from sources, not yet reviewed

Does the exact form matter?

Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.

The form that was studied

Oral

Source-linked record

Where this came from

A person wrote this into the record with the study named beside it. No reviewer has signed it off.

The form used in the studies cited on this page.

No source is stored against this line.

What is sold

Not recorded.

Nothing recorded

Where this came from

RNAWiki holds nothing here and says so rather than guessing.

Nothing further is recorded about which forms are sold.

No source is stored against this line.

What is recorded as being sold

  • 9 products list this as an active ingredient in the United States drug directory. 9 of them contain it and nothing else.

    FDA National Drug Code directory · 72640-026 · read 2026-08-29

  • They are sold as powder and tablet, film coated, taken oral.

    FDA National Drug Code directory · 72640-026 · read 2026-08-29

  • 1 published label names it as an active ingredient. 1 of them describe this substance alone, which is where its own label text on this page comes from.

    US prescribing information · a7d008cb-b273-4049-a5d2-9c6902910d58 · read 2026-08-29

  • Those labels are classed as human prescription drug.

    US prescribing information · a7d008cb-b273-4049-a5d2-9c6902910d58 · read 2026-08-29

  • NOURIANZ is oral at 3 DOSAGE FORMS AND STRENGTHS 20 mg tablets: Peach-colored, pillow-shaped, film-coated tablets with "20" debossed on one side. 40 mg tablets: Peach-colored, almond-shaped, film-coated tablets with "40" debossed on one si…, recorded as fda label in effect 2025-05-20 in the United States.

    US prescribing information · a7d008cb-b273-4049-a5d2-9c6902910d58 · read 2026-08-30

Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.

What it would be like to takeRead from sources, not yet reviewed

What you could measure

This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.

RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.

Questions worth asking

  • Which of the trials of Istradefylline studied people like me?
  • What was measured, and for how long?
  • Was the result a laboratory value or a health outcome?
  • What would we watch for, and when would we stop?

Tracking can show whether something changed for you. It cannot show what caused it.

RNAWiki records evidence. It does not say whether this substance is right for you.

What is missing or unclearRead from sources, not yet reviewed

What nobody knows yet

Open questions, each with why it is open and what would close it.

Missing populations

Which groups were under-represented in the studies has not been recorded.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Missing long-term data

No completed tested study window is recorded.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

No reviewed conclusion

RNAWiki has not yet published a reviewed conclusion for this use.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Missing interaction studies

No interaction was found in the registers checked. Not finding one is not the same as showing there is none.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Formulation uncertainty

Several salts, forms or products of Istradefylline are recorded. Results from one form may not transfer to another.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

Mechanism not reviewed

No reviewed mechanism story exists for this substance.

Why it matters. Recorded by the evidence model as a gap on this record.

What would answer it

A study that measures it, and a reviewer to sign it off.

Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.

What happened in peopleRead from sources, not yet reviewed

Check any of this yourself

Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.

Where else this substance is registered

FDA substance identifier (UNII)
2GZ0LIK7T4
RxNorm concept
2199020

Checks this page had to pass

  • Passed

    Identity resolved

    no open identity hold

  • Passed

    No unresolved merge across substance families

    no quarantine open

  • Passed

    Every public sentence names a source

    The opening statement carries the origin: Quoted from a stored source.

  • Not passed

    Trial roles classified for highlighted evidence

    No registered study is classified as testing this substance.

  • Passed

    No internal keys in reader text

    enforced by the copy-contract test over the rendered page

  • Not passed

    Safety mode resolved

    No register row and no identity class settled the question.

  • Passed

    Canonical metadata present

    slug and display name present

What is missing or unclearRead from sources, not yet reviewed

How this medicine reached us

Kept near the foot of the page. A historical event moves up only when it changes something about this substance today.

What the approval register records

  • 1 approved application covers products containing this substance. The earliest was NDA022075, approved 20190827 to KYOWA KIRIN.

    Drugs@FDA application register · NDA022075 · read 2026-08-29

  • Marketing status on the register: prescription.

    Drugs@FDA application register · NDA022075 · read 2026-08-29

  • The earliest marketing start date recorded for a listed product is 20160121.

    FDA National Drug Code directory · 72640-026 · read 2026-08-29

What is missing or unclearRead from sources, not yet reviewed

What to learn next

Ordered by what would most change how you read this page, starting with what is easiest to misunderstand.

This order is fixed in code and does not count clicks or time on the page.

What is not here

9 questions this page could not answer

These sections were prepared and left out because there was nothing to put in them. They are listed rather than hidden, so the gaps in this record are visible.

  • What was measured, goal by goal — found nothing in the sources checked.
  • How close this is to real life — found nothing in the sources checked.
  • The path through the body — found nothing in the sources checked.
  • Felt, measured, or meaningful — found nothing in the sources checked.
  • How long anything takes — found nothing in the sources checked.
  • What it may clash with — found nothing in the sources checked.
  • Other ways to the same goal — found nothing in the sources checked.
  • Claims that go past the evidence — found nothing in the sources checked.
  • What changed on this page — found nothing in the sources checked.

The record as stored

The full record, for auditing

Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.

Recorded evidence blocks (11)

On the Istradefylline label: indicated for what?


"NOURIANZ is indicated as adjunctive treatment to levodopa/carbidopa in adult patients with Parkinson's disease (PD) experiencing "off" episodes. NOURIANZ is an adenosine receptor antagonist indicated as adjunctive treatment to levodopa/carbidopa in adult patients with Parkinson's disease (PD) experiencing "off"…": indications and usage on Istradefylline's label. DailyMed label · a7d008cb-b273-4049-a5d2-9c6902910d58 · 2025-05-20

27 registered trials of Istradefylline — at which phases?


Registered studies posting no result
24 of 27

27 registered studies of Istradefylline: 12 phase2, 11 phase3, 6 phase1, 1 na or unstated, 1 phase4. CLINICALTRIALS_SNAPSHOT · 2026-09-01

18 with a PubMed record

Show the evidence
  • phase2
    12
  • phase3
    11
  • phase1
    6
  • na or unstated
    1
  • phase4
    1
  • completed
    22
3 more recorded rows
  • not yet recruiting
    2
  • terminated
    2
  • active not recruiting
    1

recorded 2026-09-01 · last checked 2026-09-04

2 of Istradefylline's trials stopped: safety, accrual/recruitment?


safety (1) and accrual/recruitment (1): Istradefylline's stop wording, clustered. CLINICALTRIALS_SNAPSHOT · 2026-09-01

"Additional long-term safety data no longer needed"; 2 of 27 registered studies

Show the evidence

Trial

  • NCT00199381
    terminated; "Additional long-term safety data no longer needed"
  • NCT05182151
    terminated; "recruitment issues"

recorded 2026-09-01 · last checked 2026-09-04

Human studies of Istradefylline used Istradefylline 40 mg — over how long?


Human studies of Istradefylline used "Istradefylline 40 mg". ClinicalTrials.gov · 2026-09-01

5 recorded entries; human; also "Istradefylline 20 mg", "Rifampin 300mg BID + istradefylline 40mg Day 8 only", "Istradefylline 20 mg or 40 mg"

Show the evidence

human

  • NCT01968031
    Istradefylline 40 mg
  • NCT01968031
    Istradefylline 20 mg
  • NCT02174250
    Rifampin 300mg BID + istradefylline 40mg Day 8 only
  • NCT02610231
    Istradefylline 20 mg or 40 mg
  • NCT05377424
    Consume 20mg of istradefylline

recorded 2026-09-01 · last checked 2026-09-04

Istradefylline's half-life is 83 hours — which schedules were studied?


83 hours, the half-life Istradefylline's label states: "The mean terminal half-life (t 1/2 ) for istradefylline at steady-state is approximately 83 hours." DailyMed label · a7d008cb-b273-4049-a5d2-9c6902910d58 · 2025-05-20

tmax 4 hours.

Show the evidence
  • half life pharmacokinetics
    83 hours; The mean terminal half-life (t 1/2 ) for istradefylline at steady-state is approximately 83 hours.
  • tmax pharmacokinetics
    4 hours; Absorption The median time to reach the maximum concentration (T max ) for istradefylline was about 4 hours under fasted dosing conditions.
  • metabolism pharmacokinetics
    Metabolism In humans, istradefylline is exclusively eliminated via metabolism.

recorded 2025-05-20 · last checked 2026-09-04

Which running trial of Istradefylline could settle function?


NCT05217498 measures Pre-Treatment Walking Speed, reading out 2028-06-30.

1 open trial; n 40; "Combining Low Oxygen Therapy and an Adenosine A2a Receptor Antagonist to Improve Functional Mobility After Spinal Cord Injury"

Show the evidence
  • Trial NCT05217498
    "Combining Low Oxygen Therapy and an Adenosine A2a Receptor Antagonist to Improve Functional Mobility After Spinal Cord Injury"; n 40; "Pre-Treatment Walking Speed"; 2028-06-30

Which 19 trials of Istradefylline posted no result?


Posted no result
19 of 19 completed trials
Registrations
NCT00006337, NCT00456586, NCT00456794, NCT00955045, NCT00199394 and NCT00199420, and 13 more
Completion dates
oldest 2002-01; newest 2016-07
Show the evidence

Trial

  • NCT00006337
    2002-01
  • NCT00456586
    2003-06
  • NCT00456794
    2003-10
  • NCT00955045
    2003-10
  • NCT00199394
    2005-11
  • NCT00199420
    2005-12
13 further recorded trials
  • NCT00199407
    2006-01
  • NCT00199355
    2006-03
  • NCT00199433
    2006-08
  • NCT00199446
    2006-10
  • NCT00250393
    2006-10
  • NCT00203957
    2007-02
  • NCT00199368
    2007-05
  • NCT00455507
    2008-08
  • NCT00955526
    2011-02
  • NCT00957203
    2012-03
  • NCT02174250
    2014-12
  • NCT02256033
    2014-12
  • NCT02609477
    2016-07

At the median, Istradefylline's trials enrolled 160 people — anything larger?


Median enrolment
160
Largest enrolment
1100
Registered trials counted
26

What do 1351 spontaneous reports say about Istradefylline — and not say?


These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.

Istradefylline appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 1351 reaction mentions were counted: dyskinesia 204; therapy non-responder 202; hallucination 172; dizziness 165. FAERS via Open Targets · CHEMBL431770 · 2026-06-24

Show the evidence
  • dyskinesia
    204
  • therapy non-responder
    202
  • hallucination
    172
  • dizziness
    165
  • constipation
    124
  • condition aggravated
    123
4 more recorded rows
  • insomnia
    108
  • tremor
    104
  • fall
    76
  • product dose omission issue
    73

recorded 2026-06-24 · last checked 2026-09-04

Which 10 reactions does Istradefylline's label not list?


condition aggravated, constipation and dizziness and 7 more reported for Istradefylline, absent from its label. FAERS via Open Targets · CHEMBL431770 · 2026-06-24

2 label terms; 10 reported and unlisted; a7d008cb-b273-4049-a5d2-9c6902910d58

Show the evidence
  • condition aggravated
    count not stated
  • constipation
    count not stated
  • dizziness
    count not stated
  • dyskinesia
    count not stated
  • fall
    count not stated
  • hallucination
    count not stated
4 more recorded rows
  • insomnia
    count not stated
  • product dose omission issue
    count not stated
  • therapy non-responder
    count not stated
  • tremor
    count not stated

recorded 2026-06-24 · last checked 2026-09-04

Istradefylline and CYP3A4: shared by which compounds?


CYP3A4 appear in Istradefylline's recorded interaction sentences, 8 in all. DailyMed label · a7d008cb-b273-4049-a5d2-9c6902910d58 · 2025-05-20

CYP3A4, CYP3A4, CYP3A4; 3 shared nodes; drug_interactions

Show the evidence

Interaction statement

  • drug_interactions
    Strong CYP3A4 inhibitors: Recommended maximum dosage with concomitant use is 20 mg once daily ( 2.2 , 7.1 ).
  • drug_interactions
    Strong CYP3A4 inducers: Avoid use ( 2.3 , 7.1 ).
  • drug_interactions
    7.1 Effect of Other Drugs on NOURIANZ Strong CYP3A4 Inhibitors Coadministration of NOURIANZ with a strong CYP3A4 inhibitor (ketoconazole) increased istradefylline AUC inf by 2.5-fold [see Clinical Pharmacology (12.3) ] .
  • drug_interactions
    Therefore, the recommended maximum dosage of NOURIANZ in patients concomitantly using strong CYP3A4 inhibitors (e.g., itraconazole, ketoconazole, clarithromycin) is 20 mg once daily [see Dosage and Administration (2.2) ].
  • drug_interactions
    Strong CYP3A4 Inducers Coadministration of NOURIANZ with a strong CYP3A4 inducer (rifampin) decreased istradefylline C max and AUC inf by 45% and 81%, respectively [see Clinical Pharmacology (12.3) ] .
  • drug_interactions
    Therefore, it is recommended to avoid use of NOURIANZ with strong CYP3A4 inducers (e.g., carbamazepine, rifampin, phenytoin, St.
2 more recorded rows
  • Interaction statement drug_interactions
    7.2 Effect of NOURIANZ on Other Drugs CYP3A4 Substrates Coadministration of NOURIANZ 20 mg with a CYP3A4 substrate (midazolam) did not affect the CYP3A4 substrate exposure, while concomitant administration of NOURIANZ 40 mg increased the CYP3A4 substrate (atorvastatin) C max and AUC inf by 1.5-fold [see Clinical Pharmacology (12.3) ] .
  • Interaction statement drug_interactions
    Monitor for an increase in adverse reactions of concomitant drugs that are CYP3A4 substrates when coadministering with NOURIANZ 40 mg.

CYP3A4

  • FINGOLIMOD LAURYL SULFATE, ERYTHROMYCIN LACTOBIONATE, FOSAPREPITANT DIMEGLUMINE, TAFAMIDIS MEGLUMINE, Arimoclomol, Beclometasone, Rasagiline, Sofpironium
  • FINGOLIMOD LAURYL SULFATE, ERYTHROMYCIN LACTOBIONATE, FOSAPREPITANT DIMEGLUMINE, TAFAMIDIS MEGLUMINE, Arimoclomol, Beclometasone, Rasagiline, Sofpironium
  • FINGOLIMOD LAURYL SULFATE, ERYTHROMYCIN LACTOBIONATE, FOSAPREPITANT DIMEGLUMINE, TAFAMIDIS MEGLUMINE, Arimoclomol, Beclometasone, Rasagiline, Sofpironium

recorded 2025-05-20 · last checked 2026-09-04

Where it is registered
Identifiers, relations and other names

The exact record

ChEMBL id
CHEMBL431770
PubChem CID
5311037
CAS number
155270-99-8
RxCUI
2199015
InChIKey
IQVRBWUUXZMOPW-PKNBQFBNSA-N
Also called
Istradefilina, Nouriast, ISTRADEFYLLINE [JAN], ISTRADEFYLLINE [MI], ISTRADEFYLLINE [ORANGE BOOK], ISTRADEFYLLINE [USAN], Istradefylline [WHO-DD], istradefylline [INN]
Development code
KW-6002
Trade name
Nourianz, Nouryant
Sources (6)

Sources

ChEMBL ATC CC BY-SA · ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work

How these records are assembled · Which registers were checked

Index-quality checks
  • identity passed: no open identity hold
  • required summary fields resolved: 4 required field(s) not terminal: Why people use it, Best-supported result, Biggest unanswered question, Human evidence
  • public claims reviewed: 0 reviewed claim(s); drafts are never rendered
  • source coverage passed: 6 source rows
  • no critical contamination: no quarantine open
  • canonical metadata passed: slug and display name present
  • no raw internal fields: enforced by the copy-contract test over the rendered page

This is a record of evidence. It is not medical advice, and it does not say this substance suits you. Nothing here says any substance on RNAWiki is appropriate for a child.