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Methylnaltrexone

  • 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 Methylnaltrexone does in the body

Opioid-induced constipation

From the FDA-approved label: Methylnaltrexone is a selective antagonist of opioid binding at the mu-opioid receptor. As a quaternary amine, the ability of methylnaltrexone to cross the blood-brain barrier is restricted. This allows methylnaltrexone to function as a peripherally-acting mu-opioid receptor antagonist in tissues such as the gastrointestinal tract, thereby decreasing the constipating effects of opioids without impacting opioid-mediated analgesic effects on the central nervous system (CNS).

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

  • Its recorded molecular formula is C21H26NO4Br, weighing 436.36.

    US prescribing information · c488fb7c-0a5b-487c-b452-996809d1cb99 · read 2026-08-30

Where each sentence above came from

No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.

Shown as the opening line on this page.

No statement of the main limit is recorded.

The four opening statements run to 82 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.

Number of Participants With Treatment-Emergent Adverse Events (TEAEs)

The study did not show it

Who was studied
NCT00804141
How many people
1040
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

Average Percentage of Dosing Days That Resulted in Rescue-Free Bowel Movements (RFBMs) Within 4 Hours of Dosing During Weeks 1 to 4

The study did not show it

Who was studied
NCT01186770
How many people
804
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

Effects of MNTX on QTcI duration

The study did not show it

Who was studied
NCT01363323
How many people
546
Study design
Phase 1
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

Time to First Bowel Movement

The study did not show it

Who was studied
NCT00401375
How many people
524
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

Primary Objective: In subjects who have undergone segmental colectomy, the time between the end of surgery and first bowel movement is significantly shorter with the MOA-728 regimen than with a placebo regimen.

The study did not show it

Who was studied
NCT00387309
How many people
495
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

Percentage of Patients Having a Rescue-free Bowel Movement (RFBM) Within 4 Hours of the First Dose

The study did not show it

Who was studied
NCT00529087
How many people
460
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.

  • • RELISTOR is an opioid antagonist. RELISTOR tablets and RELISTOR injection are indicated for the treatment of opioid-induced constipation (OIC) in adults with chronic non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage escalation.

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 of RELISTOR tablets and injection have not been established in pediatric patients.”

    US prescribing information · c488fb7c-0a5b-487c-b452-996809d1cb99 · read 2026-08-30

  • On older people, the label states: “Of the total number of patients in clinical studies of RELISTOR tablets, a total of 136 patients (10%) were aged 65 years and older, while 23 (2%) were aged 75 and older.”

    US prescribing information · c488fb7c-0a5b-487c-b452-996809d1cb99 · read 2026-08-30

  • On people who are pregnant, the label states: “Risk Summary The limited available data with RELISTOR in pregnant women are not sufficient to inform a drug-associated risk for major birth defects and miscarriages.”

    US prescribing information · c488fb7c-0a5b-487c-b452-996809d1cb99 · read 2026-08-30

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

    US prescribing information · c488fb7c-0a5b-487c-b452-996809d1cb99 · read 2026-08-30

  • On people with reduced liver function, the label states: “Tablets In a study of subjects with varying degrees of hepatic impairment receiving a 450 mg dose of RELISTOR tablets, there was a significant increase in systemic exposure of methylnaltrexone for subjects with moderate (Child-Pugh Class B) and severe (Child-Pugh Class C) hepatic impairment compared to healthy subjects with normal hepatic function [see Clinical Pharmacology ( 12.3 )] .”

    US prescribing information · c488fb7c-0a5b-487c-b452-996809d1cb99 · read 2026-08-30

  • On people with reduced kidney function, the label states: “In a study of subjects with varying degrees of renal impairment receiving RELISTOR injection subcutaneously, there was a significant increase in the exposure to methylnaltrexone in subjects with moderate and severe renal impairment (creatinine clearance less than 60 mL/minute as estimated by Cockcroft-Gault) compared to healthy subjects [see Clinical Pharmacology ( 12.3 )] .”

    US prescribing information · c488fb7c-0a5b-487c-b452-996809d1cb99 · 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, solution, injection, solution, given by the oral, subcutaneous 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

  • Relistor is oral at 3 DOSAGE FORMS AND STRENGTHS • Tablets : • 150 mg methylnaltrexone bromide supplied as film-coated, white, round, biconvex, debossed with “REL” on one side and plain on the other side., recorded as fda label in effect 2024-05-01 in the United States.

    US prescribing information · c488fb7c-0a5b-487c-b452-996809d1cb99 · 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 Methylnaltrexone 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 Methylnaltrexone 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 peopleNothing found in the sources checked

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.

Nothing found in the sources checked

No traced study record is stored for this substance.

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

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: Written into the record, not signed off.

  • 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

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

10 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.
  • How this medicine reached us — 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 (8)

On the Methylnaltrexone label: indicated for what?


"• RELISTOR is an opioid antagonist. RELISTOR tablets and RELISTOR injection are indicated for the treatment of opioid-induced constipation (OIC) in adults with chronic non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage…": indications and usage on Methylnaltrexone's label. DailyMed label · c488fb7c-0a5b-487c-b452-996809d1cb99 · 2024-05-01

40 registered trials of Methylnaltrexone — at which phases?


Registered studies posting no result
25 of 40

40 registered studies of Methylnaltrexone: 13 phase4, 11 phase3, 8 phase1, 6 phase2, 3 na, 1 na or unstated. CLINICALTRIALS_SNAPSHOT · 2026-09-01

59 with a PubMed record

Show the evidence
  • phase4
    13
  • phase3
    11
  • phase1
    8
  • phase2
    6
  • na
    3
  • na or unstated
    1
5 more recorded rows
  • completed
    27
  • withdrawn
    5
  • terminated
    3
  • unknown
    3
  • recruiting
    2

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

7 of Methylnaltrexone's trials stopped: safety, accrual/recruitment, other?


safety (1), accrual/recruitment (2) and other (4): Methylnaltrexone's stop wording, clustered. CLINICALTRIALS_SNAPSHOT · 2026-09-01

"Withdrawn \[This study was terminated early by Wyeth, prior to dosing any subjects, for business reasons not related to safety."; 7 of 40 registered studies

Show the evidence

Trial

  • NCT00858754
    withdrawn; "Withdrawn \[This study was terminated early by Wyeth, prior to dosing any subjects, for business reasons not related to safety."
  • NCT00949377
    withdrawn; "Unable to recruit enough patients at a single center."
  • NCT01117376
    terminated; "The study was prematurely terminated because of unavailibility of Methylnaltrexone in the region"
  • NCT01360372
    withdrawn; "No eligible subjects identified"
  • NCT02977286
    terminated; "Poor enrollment"
  • NCT04083651
    withdrawn; "Due to pandemic challenges and consideration of a different study design in the future."
  • 1 further recorded trial NCT04151719
    withdrawn; "Due to pandemic challenges and consideration of a different study design in the future."

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

Human studies of Methylnaltrexone used Methylnaltrexone Bromide 150 mg Oral Tablet — over how long?


Human studies of Methylnaltrexone used "Methylnaltrexone Bromide 150 mg Oral Tablet". ClinicalTrials.gov · 2026-09-01

2 recorded entries; human; also "Methylnaltrexone Bromide 12 MG/0.6 ML Subcutaneous Solution [RELISTOR]_#1"

Show the evidence

human

  • NCT03523520
    Methylnaltrexone Bromide 150 mg Oral Tablet
  • NCT03523520
    Methylnaltrexone Bromide 12 MG/0.6 ML Subcutaneous Solution [RELISTOR]_#1

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

Methylnaltrexone's half-life is 15 hours — which schedules were studied?


15 hours, the half-life Methylnaltrexone's label states: "Elimination Following oral administration of a single 450 mg dose of RELISTOR tablets, concentrations of methylnaltrexone declined in multiphasic manner with a terminal half-life (t 1/2 ) of approximately 15 hours." DailyMed label · c488fb7c-0a5b-487c-b452-996809d1cb99 · 2024-05-01

tmax 1.5 hours.

Show the evidence
  • half life pharmacokinetics
    15 hours; Elimination Following oral administration of a single 450 mg dose of RELISTOR tablets, concentrations of methylnaltrexone declined in multiphasic manner with a terminal half-life (t 1/2 ) of approximately 15 hours.
  • tmax pharmacokinetics
    1.5 hours; Absorption Tablets Following administration of a single 450 mg dose of RELISTOR tablets in OIC patients or healthy subjects, peak concentrations (C max ) of methylnaltrexone were observed at approximately 1.5 hours.
  • metabolism pharmacokinetics
    Metabolism In an intravenous mass balance study, approximately 44% of the administered radioactivity was recovered in the urine over 24 hours with 5 distinct metabolites.

recorded 2024-05-01 · last checked 2026-09-04

Which 13 trials of Methylnaltrexone posted no result?


Posted no result
13 of 13 completed trials
Registrations
NCT01366339, NCT01363323, NCT01367509, NCT01366365, NCT01366378 and NCT00387309, and 7 more
Completion dates
oldest 2003-12; newest 2017-12
Show the evidence

Trial

  • NCT01366339
    2003-12
  • NCT01363323
    2005-02
  • NCT01367509
    2005-06
  • NCT01366365
    2006-11
  • NCT01366378
    2007-02
  • NCT00387309
    2007-11
7 further recorded trials
  • NCT01012960
    2010-01
  • NCT01366326
    2010-08
  • NCT01596764
    2012-01
  • NCT03014843
    2014-01
  • NCT01773096
    2015-05
  • NCT01889290
    2016-06
  • NCT02942550
    2017-12

At the median, Methylnaltrexone's trials enrolled 31 people — anything larger?


Median enrolment
31
Largest enrolment
1040
Registered trials counted
40

Methylnaltrexone and CYP1A2, CYP2B6 and CYP2D6: shared by which compounds?


CYP1A2, CYP2B6 and CYP2D6 appear in Methylnaltrexone's recorded interaction sentences, 8 in all. DailyMed label · c488fb7c-0a5b-487c-b452-996809d1cb99 · 2024-05-01

CYP1A2, CYP2A6, CYP2B6, CYP2C19, CYP2C8, CYP2C9; 27 shared nodes; drug_interactions, pharmacokinetics

Show the evidence

Interaction statement

  • drug_interactions
    7.2 Drugs Metabolized by Cytochrome P450 Isozymes In healthy subjects, a subcutaneous dose of 0.3 mg/kg of RELISTOR did not significantly affect the metabolism of dextromethorphan, a CYP2D6 substrate.
  • drug_interactions
    7.2 Drugs Metabolized by Cytochrome P450 Isozymes In healthy subjects, a subcutaneous dose of 0.3 mg/kg of RELISTOR did not significantly affect the metabolism of dextromethorphan, a CYP2D6 substrate.
  • pharmacokinetics
    Drug Interaction Studies Effect of Methylnaltrexone and its Metabolites on CYP Enzymes In vitro, methylnaltrexone did not significantly inhibit or induce the activity of cytochrome P450 (CYP) isozymes CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, or CYP3A4.
  • pharmacokinetics
    In addition, methylnaltrexone did not induce CYP2E1.
  • pharmacokinetics
    In vitro, the methylnaltrexone metabolites, methylnaltrexone sulfate, methyl-6α-naltrexol and methyl-6β-naltrexol did not inhibit CYP isozymes CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, or CYP3A4.
  • pharmacokinetics
    The metabolites of methylnaltrexone did not induce activity of CYP1A2, CYP2B6, or CYP3A4.
2 more recorded rows
  • Interaction statement pharmacokinetics
    Effect of Methylnaltrexone and its Metabolites on Transporters Based on the in vitro studies, methylnaltrexone and its three major metabolites, methylnaltrexone sulfate, methyl-6α-naltrexol and methyl-6β-naltrexol, are unlikely to have clinically meaningful in vivo drug-drug interactions via inhibition of P-glycoprotein (P-gp), Breast Cancer Resistance Protein (BCRP), Multidrug Resistance Protein…
  • Interaction statement pharmacokinetics
    Methylnaltrexone : Methylnaltrexone was a substrate of OCT1, OCT2, MATE1, and MATE2-K, but not a substrate for P-gp, BCRP, MRP2, OATP1B1, OATP1B3, OAT1 and OAT3.
  • CYP1A2
    FINGOLIMOD LAURYL SULFATE, FOSAPREPITANT DIMEGLUMINE, TAFAMIDIS MEGLUMINE, Arimoclomol, Rasagiline, Sofpironium, Golodirsen, Tinidazole
  • CYP2A6
    FINGOLIMOD LAURYL SULFATE, Rasagiline, Naldemedine, Tivozanib, Metaxalone, Selegiline, Trametinib, Fingolimod
  • CYP2B6
    FINGOLIMOD LAURYL SULFATE, TAFAMIDIS MEGLUMINE, Arimoclomol, Sofpironium, Bupropion, Golodirsen, Tinidazole, Naldemedine
  • CYP2C19
    FINGOLIMOD LAURYL SULFATE, FOSAPREPITANT DIMEGLUMINE, TAFAMIDIS MEGLUMINE, Arimoclomol, Rasagiline, Golodirsen, Naldemedine, Etravirine
  • CYP2C8
    FINGOLIMOD LAURYL SULFATE, TAFAMIDIS MEGLUMINE, Arimoclomol, Golodirsen, Naldemedine, Lapatinib, Tivozanib, Metaxalone
  • CYP2C9
    FINGOLIMOD LAURYL SULFATE, FOSAPREPITANT DIMEGLUMINE, TAFAMIDIS MEGLUMINE, Arimoclomol, Rasagiline, Golodirsen, Tinidazole, Naldemedine

CYP2D6

  • FINGOLIMOD LAURYL SULFATE, Darunavir Propylene Glycolate, FOSAPREPITANT DIMEGLUMINE, TAFAMIDIS MEGLUMINE, Arimoclomol, Rasagiline, Sofpironium, Fluoxetine
  • FINGOLIMOD LAURYL SULFATE, Darunavir Propylene Glycolate, FOSAPREPITANT DIMEGLUMINE, TAFAMIDIS MEGLUMINE, Arimoclomol, Rasagiline, Sofpironium, Fluoxetine
  • CYP2E1
    FINGOLIMOD LAURYL SULFATE, FOSAPREPITANT DIMEGLUMINE, Rasagiline, Tinidazole, Naldemedine, Alosetron, Metaxalone, Uridine triacetate
  • CYP3A4
    FINGOLIMOD LAURYL SULFATE, ERYTHROMYCIN LACTOBIONATE, FOSAPREPITANT DIMEGLUMINE, TAFAMIDIS MEGLUMINE, Arimoclomol, Beclometasone, Rasagiline, Sofpironium

BCRP

  • TAFAMIDIS MEGLUMINE, Arimoclomol, Ceftobiprole Medocaril, Deoxycholic acid, Golodirsen, Naldemedine, Eravacycline, Omadacycline
  • TAFAMIDIS MEGLUMINE, Arimoclomol, Ceftobiprole Medocaril, Deoxycholic acid, Golodirsen, Naldemedine, Eravacycline, Omadacycline
  • MATE1
    TAFAMIDIS MEGLUMINE, Arimoclomol, Ceftobiprole Medocaril, Sofpironium, Golodirsen, Eravacycline, Prucalopride, Chenodeoxycholic acid
  • MATE2-K
    TAFAMIDIS MEGLUMINE, Arimoclomol, Sofpironium, Golodirsen, Eravacycline, Prucalopride, Chenodeoxycholic acid, Pivmecillinam

MRP2

  • Ceftobiprole Medocaril, Deoxycholic acid, Golodirsen, Omadacycline, Prucalopride, Sonidegib, Trametinib, Gadobenate Dimeglumine
  • Ceftobiprole Medocaril, Deoxycholic acid, Golodirsen, Omadacycline, Prucalopride, Sonidegib, Trametinib, Gadobenate Dimeglumine
  • OAT1
    TAFAMIDIS MEGLUMINE, Arimoclomol, Ceftobiprole Medocaril, Deoxycholic acid, Golodirsen, Naldemedine, Eravacycline, Prucalopride

OAT3

  • TAFAMIDIS MEGLUMINE, Arimoclomol, Ceftobiprole Medocaril, Deoxycholic acid, Golodirsen, Naldemedine, Pemetrexed, Eravacycline
  • TAFAMIDIS MEGLUMINE, Arimoclomol, Ceftobiprole Medocaril, Deoxycholic acid, Golodirsen, Naldemedine, Pemetrexed, Eravacycline
  • OATP1B1
    FINGOLIMOD LAURYL SULFATE, TAFAMIDIS MEGLUMINE, Arimoclomol, Ceftobiprole Medocaril, Deoxycholic acid, Golodirsen, Naldemedine, Eravacycline

recorded 2024-05-01 · last checked 2026-09-04

Where it is registered
Identifiers, relations and other names

The exact record

PubChem CID
16089915
CAS number
916055-93-1
RxCUI
29899
InChIKey
JVLBPIPGETUEET-WIXLDOGYSA-O
Salt form
Methylnaltrexone Bromide
Trade name
Relistor
Also called
METHYLNALTREXONE CATION, METHYLNALTREXONE ION, METHYLNALTREXONE [MI], METHYLNALTREXONE [VANDF], MNTX, Methylnaltrexone [WHO-DD]
Development code
MRZ-2663
Sources (5)

Sources

  • CLINICALTRIALS_SNAPSHOT K1:0RK7M7IABE ·
  • ClinicalTrials.gov clinicaltrials.gov ·
  • drugsfda+ema drugsfda+ema ·
  • DailyMed label c488fb7c-0a5b-487c-b452-996809d1cb99 ·
  • Drugs@FDA K1:0RK7M7IABE ·

ClinicalTrials.gov — US Government work · 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: 5 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

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