This page shows what was measured, who it was measured in, and what that does not settle.
What Primaquine does in the body
The radical cure (prevention of relapse) of vivax malaria
From the FDA-approved label: Primaquine phosphate is an 8-aminoquinoline antimalarial drug. The mechanism of action has not been fully established. The major assumptions are an inhibition of the mitochondrial system of dormant parasites, and an oxidative stress generated through reactive metabolites in infected cells. In humans, primaquine phosphate activity is probably related to hydroxylated metabolites generated intrahepatically by CYP2D6.
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.
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 81 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.
Stand-in result
A stand-in result is a number measured because the real result takes too long.
A picture of it, and where the picture fails
It is like judging a journey by the speedometer rather than by arriving.
Where that stops being true. Speed does predict arrival. Many stand-in results do not predict the real one.
What people get wrong. A stand-in result is often reported as the result itself.
A surrogate endpoint substituted for a clinical endpoint, valid only where the substitution has been shown to hold.
Enzyme
An enzyme is a protein that speeds up one chemical change.
A picture of it, and where the picture fails
An enzyme is like a machine on a production line doing one cut.
Where that stops being true. A machine is switched on and off by a person. Enzymes are controlled by the cell.
What people get wrong. Enzymes are thought to be used up. They are not; they work again and again.
A catalytic protein that lowers the activation energy of a specific reaction.
Receptor
A receptor is a part of a cell that a signal fits into.
A picture of it, and where the picture fails
A receptor is like a lock waiting for one key.
Where that stops being true. A lock either opens or does not. A receptor can be half-triggered, or worn out.
What people get wrong. Fitting a receptor is read as causing a benefit. It causes a step, and nothing more.
A protein that binds a specific ligand and converts that binding into a cellular response.
Pathway
A pathway is a chain of steps inside a cell, each one setting off the next.
A picture of it, and where the picture fails
A pathway is like a row of dominoes.
Where that stops being true. Dominoes fall one way. Pathways loop back and can switch themselves off.
What people get wrong. Changing one step is read as changing the outcome. Other steps often absorb it.
An ordered series of molecular interactions producing a defined cellular change.
What happened in people◇Read 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.
Change in malaria annual parasite incidence (API)
✗ The study did not show it
Who was studied
NCT04241705
How many people
48960
Study design
Not applicable
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
Community-level PCR-based P. falciparum prevalence in sampled villages
✗ The study did not show it
Who was studied
NCT03783299
How many people
39968
Study design
Phase 4
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
Cumulative notified malaria incidence in the MDA and control Shehias
✗ The study did not show it
Who was studied
NCT02721186
How many people
22500
Study design
Not applicable
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
Proportion of individuals with PCR detectable P. vivax blood-stage infections 6 months after the second round of PvSeroTAT or 6 months after the second round of blood sampling in the control clusters.
✗ The study did not show it
Who was studied
NCT06923592
How many people
19200
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
Plasmodium falciparum carriage reservoir at the end of the high transmission season (step 0)
✗ The study did not show it
Who was studied
NCT07281443
How many people
18000
Study design
Not applicable
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
Confirmed P. falciparum and P. vivax malaria parasite incidence
✗ The study did not show it
Who was studied
NCT05052502
How many people
14977
Study design
Not applicable
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 happened in people◇Read from sources, not yet reviewed
How close this is to real life
The top step is something a person would feel or care about. The bottom is a guess from software. Filled steps are where evidence exists for this substance.
□Living longer, or avoiding a major eventNo evidence recorded. Death, a heart attack, a stroke, a hospital stay.No registered study measures this.
□What a body can do day to dayNo evidence recorded. Walking, dressing, breathing, recovering.No registered study measures this.
□Measured performanceNo evidence recorded. How much was lifted, how far was run, how fast.No registered study measures this.
□Symptoms and quality of lifeNo evidence recorded. Pain, tiredness, mood, sleep, as the person rated it.No registered study measures this.
■A number that stands in for healthEvidence recorded. Cholesterol, blood sugar, bone density. A stand-in, not the thing itself.3 registered measures of this kind.
■A step measured inside a personEvidence recorded. Something measured in human tissue or human cells.A human record sits on the stored organism ladder.
■AnimalsEvidence recorded. Mice, rats, dogs. Useful for ideas, not proof about people.Stored records in Mouse. A result in animals says what to test next. It does not say what happens in people.
■Cells in a dishEvidence recorded. Cells or chemistry on a bench, far from a whole body.Stored mechanism abstracts describe steps measured in cells or tissue.
□A guess from softwareNo evidence recorded. Nobody measured it. RNAWiki never publishes one as a finding.RNAWiki stores no prediction for this record. Software can suggest a link. RNAWiki does not publish one as a finding.
Higher on these steps means closer to something a person would feel. It does not mean better done.
What it would be like to take◇Read from sources, not yet reviewed
Felt, measured, or meaningful
Three different things that get called the same word. Registered studies measured all three, and mixing them is how a blood test becomes a health claim.
Felt
Things a person could notice without a test.
No registered study measured anything of this kind.
Measured
Things only a test, a scale or a device shows.
area under the concentration time curve
haemoglobin compared to the baseline
haemoglobin
Meaningful
Things that change how a life goes, not only a number.
No registered study measured anything of this kind.
A registered study says what someone planned to measure. It does not say what they found. A number moving is not the same as a life going better. The two are shown apart here.
Felt, but not shown to help. A person notices a change. No study showed it leads anywhere good.
Measured, but not felt. A number moves. The person notices nothing. Both can be true.
Measured, but not shown to matter. A number moves in the good direction. Nobody showed that lives went better.
Matters, but takes years. The result that counts may take longer than anyone would keep watching.
Names that fit none of the three (9)
incidence
qrt pcr
adverse events
early treatment failure
late clinical failure
late parasitological failure
adequate clinical and parasitological response
relative infant dose
pharmacokinetics volume of distribution
These are harms, study-process measures, or names the rules did not recognise. They are shown rather than dropped.
What it would be like to take◇Read from sources, not yet reviewed
How long anything takes
Nine different lengths of time that get confused with each other. None of them is worked out from another.
Before anything is noticed.RNAWiki does not store this separately, and never works it out from another figure on this page.
Before a test result moves.RNAWiki does not store this separately, and never works it out from another figure on this page.
Before performance moves.RNAWiki does not store this separately, and never works it out from another figure on this page.
How long the result was watched.No finished study window is recorded for a study that tested this substance.
How long people took it.How long people actually took it is not stored. The study window is not the same thing.
How long people were followed.Follow-up length is not stored separately. It is never read off the study window, which would be a different thing.
How fast the body clears it. 22 hours hours
Read from the label, which states: “CYP2D6 -Direct conjugations Elimination Major route of elimination Metabolism Apparent Clearance (CL/F) 37.6 ± 14.7 L/hr Mean terminal half-life (t 1/2 ) The mean terminal half-life of carboxyprimaquine is approximately 22 hours 5.6 ± 1.0 hours % of dose excreted in urine Oral administration of [ 14 C]-primaquine in healthy participants; no data in feces , The main circulating metabolite, carboxyp”
How long effects linger.RNAWiki does not store this separately, and never works it out from another figure on this page.
Beyond the studies. Nothing is recorded about the long term.
The longest finished study sets the edge of what anyone measured.
A study window is not how long people took it, and neither is how long they were followed. Where RNAWiki holds only one of the three, it shows one.
What is missing or unclear◇Read 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.
Primaquine phosphate Tablets are indicated for the radical cure (prevention of relapse) of vivax malaria.
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 · 1bfbf4ae-81b8-4160-a00d-6322aadd4b59 · read 2026-08-30
On older people, the label states: “Clinical studies of Primaquine phosphate Tablets did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects.”
US prescribing information · 1bfbf4ae-81b8-4160-a00d-6322aadd4b59 · read 2026-08-30
On people who are pregnant, the label states: “Safe usage of Primaquine phosphate Tablets in pregnancy has not been established.”
US prescribing information · 1bfbf4ae-81b8-4160-a00d-6322aadd4b59 · read 2026-08-30
On people who are breastfeeding, the label states: “The presence of primaquine and its major metabolite in breast milk and infant plasma were evaluated in a published study of 21 G6PD-normal lactating women and their G6PD-normal infants aged 28 days or older.”
US prescribing information · 1bfbf4ae-81b8-4160-a00d-6322aadd4b59 · 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 take◇Read 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 for a different goal
The studies measured something else entirely.
On this record: Some registered studies measured things that match no goal on this page.
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 (10)
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 take◇Read 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 take∅Nothing 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 unclear◇Read 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 · 42973-177 · read 2026-08-29
They are sold as powder, tablet and tablet, film coated, taken oral.
FDA National Drug Code directory · 42973-177 · read 2026-08-29
The regulator's established pharmacologic class for it is antimalarial [epc].
FDA National Drug Code directory · 42973-177 · read 2026-08-29
5 published labels name it as an active ingredient. 5 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 0c8c2bc6-428b-40b6-8114-6df80290878d · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 0c8c2bc6-428b-40b6-8114-6df80290878d · read 2026-08-29
Primaquine Phosphate is oral at HOW SUPPLIED Primaquine phosphate Tablets are supplied as pink, convex, discoid, film-coated tablets of 26.3 mg (= 15 mg base), printed with a "W" and "P97" on one side., recorded as fda label in effect 2026-02-11 in the United States.
US prescribing information · 1bfbf4ae-81b8-4160-a00d-6322aadd4b59 · 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 take◇Read 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 Primaquine 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 unclear◇Read 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 Primaquine 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 people◇Read 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.
◇Read from sources, not yet reviewed
No traced study record is stored for this substance.
Built from stored sources by fixed rules. No reviewer has signed it off.
How many documents were read
5 documents were read for this substance.
RNAWiki source record
4 of them state the same bioavailability, and they agree.
RNAWiki source record
4 of them state the same proteinBinding, and they agree.
RNAWiki source record
2 of them state the same volumeOfDistribution, and they agree.
RNAWiki source record
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 unclear◇Read 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
5 approved applications cover products containing this substance. The earliest was NDA008316, approved 19520123 to SANOFI AVENTIS US.
This order is fixed in code and does not count clicks or time on the page.
What is not here
6 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.
The path through the body — 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 (13)
Q1
What did Primaquine's largest trial (39968 people) and its longest (6.5 years) measure?
39968 people in Primaquine's largest registered study, 6.5 years in its longest registered window, measuring Haemoglobin concentration. ClinicalTrials.gov · 2026-09-01
19 phase4, 18 phase2, 15 phase3, 13 phase1, 10 na, 9 na or unstated; NCT02364583; 2016-12; no ageing endpoint recorded. Last human test completed 2025, NCT05540470.
Interpretation These counts include studies where Primaquine was a comparison treatment, a background treatment or an exposure in an observational study, and the longest window may be a planned end date. Trial roles have not yet been classified for this record.
Show the evidence
phase4
19
phase2
18
phase3
15
phase1
13
na
10
na or unstated
9
1 more recorded row
Last recorded human testNCT05540470
2025-04-25
recorded 2026-09-01 · last checked 2026-09-04
Q2
From mouse to human: where has Primaquine shown lifespan?
"study met study halting rules"; 4 of 76 registered studies
Show the evidence
Trial
NCT03337152
terminated; "study met study halting rules"
NCT04280692
suspended; "Study halted prematurely due to US FDA clinical hold on PfSPZ Challenge"
NCT04984759
withdrawn; "Local EC requested that the arms of study be submitted as separate protocols so they could respond to the different risk of each arm. In response investigators have withdrawn this protocol and begun separate submissions, starting with…"
NCT05232227
withdrawn; "Trial terminated by funder"
recorded 2026-09-01 · last checked 2026-09-04
Q4
Human studies of Primaquine used primaquine 0.5 mg/kg/day — over how long?
5 recorded entries; human; also "Primaquine 15mg", "Primaquine 15mg (Part2 )", "Daily primaquine (0.5 mg/kg per day) for 14 days given with food food and water"
Show the evidence
human
NCT01076868
primaquine 0.5 mg/kg/day
NCT01376167
Primaquine 15mg
NCT01376167
Primaquine 15mg (Part2 )
NCT07060404
Daily primaquine (0.5 mg/kg per day) for 14 days given with food food and water
NCT07060404
Daily primaquine 1 mg/kg per day for 7 days given with food and water
recorded 2026-09-01 · last checked 2026-09-04
Q5
Primaquine's half-life is 22 hours — which schedules were studied?
22 hours, the half-life Primaquine's label states. openfda-label · 3f16166d-678e-51aa-e054-00144ff88e88 · 2026-08-30
bioavailability 70 % %.
Show the evidence
half life
22 hours hours; CYP2D6 -Direct conjugations Elimination Major route of elimination Metabolism Apparent Clearance (CL/F) 37.6 ± 14.7 L/hr Mean terminal half-life (t 1/2 ) The mean terminal half-life of carboxyprimaquine is approximately 22 hours 5.6 ± 1.0 hours % of dose excreted in urine Oral administration of [ 14 C]-primaquine in healthy participants; no data in feces , The main circulating metabolite, carboxyp
tmax
PK Parameter a Day Primaquine Carboxyprimaquine C max (ng/mL) 1 50.7 ± 21.2 291 ± 52 C max (ng/mL) 14 49.7 ± 14.4 432 ±112 AUC or AUC 0-24 (μg/mL*h) b 1 0.48 ± 0.26 5.15 ± 1.01 AUC or AUC 0-24 (μg/mL*h) b 14 0.49 ± 0.19 7.24 ± 1.82 Primaquine Absorption Bioavailability c >70 % T max 2.3 ± 1.1 hours Effect of food on Primaquine Phosphate Tablet (relative to fasting) d Geometric mean [95%…
bioavailability
70 % %; AUC or AUC 0–24 (µg/mL*h) AUC for primaquine, AUC 0–24 for carboxyprimaquine 1 0.48 ± 0.26 5.15 ± 1.01 AUC or AUC 0–24 (µg/mL*h) 14 0.49 ± 0.19 7.24 ± 1.82 Primaquine Absorption Bioavailability Healthy participants >70 % T max 2.3 ± 1.1 hours Effect of food on Primaquine Phosphate Tablet (relative to fasting) Values refer to increase in mean systemic exposure with bread and butter: 82% fat, ~28g
metabolism
PK Parameter a Day Primaquine Carboxyprimaquine C max (ng/mL) 1 50.7 ± 21.2 291 ± 52 C max (ng/mL) 14 49.7 ± 14.4 432 ±112 AUC or AUC 0-24 (μg/mL*h) b 1 0.48 ± 0.26 5.15 ± 1.01 AUC or AUC 0-24 (μg/mL*h) b 14 0.49 ± 0.19 7.24 ± 1.82 Primaquine Absorption Bioavailability c >70 % T max 2.3 ± 1.1 hours Effect of food on Primaquine Phosphate Tablet (relative to fasting) d Geometric mean [95%…
recorded 2026-08-30 · last checked 2026-09-04
Q6
Could one person measure Primaquine's effect on incidence?
Incidence: measured in Primaquine's trials.
Interpretation incidence is the recorded endpoint.
Show the evidence
biomarkers
incidence; 2026-09-01
qrt pcr; 2026-09-01
adverse events; 2026-09-01
early treatment failure; 2026-09-01
area under the concentration time curve; 2026-09-01
haemoglobin compared to the baseline; 2026-09-01
6 more recorded rows
biomarkers
haemoglobin; 2026-09-01
biomarkers
late clinical failure; 2026-09-01
biomarkers
late parasitological failure; 2026-09-01
biomarkers
adequate clinical and parasitological response; 2026-09-01
biomarkers
relative infant dose; 2026-09-01
biomarkers
pharmacokinetics volume of distribution; 2026-09-01
half life
2026-09-04; halfLife; hours; 22 hours; 2026-08-30
human trials at or under30
13
smallest human trial
0; NCT04984759; PHASE4; the smallest recorded human enrolment at or below 30; the registry states no direction of its result; WITHDRAWN
Q7
Which of adequate clinical and parasitological response, adverse events and area under the concentration time curve did Primaquine's trials measure?
adequate clinical and parasitological response, adverse events and area under the concentration time curve lead 12 outcome terms across Primaquine's trials. ClinicalTrials.gov · 2026-09-01
Interpretation early treatment failure, area under the concentration time curve, haemoglobin compared to the baseline, haemoglobin, late clinical failure and late parasitological failure follow.
Show the evidence
incidence
1
qrt pcr
1
adverse events
1
early treatment failure
1
area under the concentration time curve
1
haemoglobin compared to the baseline
1
6 more recorded rows
haemoglobin
1
late clinical failure
1
late parasitological failure
1
adequate clinical and parasitological response
1
relative infant dose
1
pharmacokinetics volume of distribution
1
recorded 2026-09-01 · last checked 2026-09-04
Q8
Which of Primaquine's 4 ongoing trials reports first?
Microscopy positive P. vivax recurrence after radical treatment up to month 4; The incidence risk of vivax parasitaemia; latest 2028-02-07
Show the evidence
Trial
NCT04704999
"Southeast Asia Dose Optimization of Tafenoquine"; n 820; "Microscopy positive P. vivax recurrence after radical treatment up to month 4"; 2028-02-07
NCT06148792
"A Revised Tafenoquine Dose to Improve Radical Cure for Vivax Malaria"; n 1090; "The incidence risk of vivax parasitaemia"; 2027-03-01
NCT06666491
"An Interventional Study to Compare the Efficacy and Safety of Tafenoquine (TQ) and Primaquine (PQ) When Either Are Taken Together With Chloroquine (CQ) for the Treatment of P. Vivax Malaria in Indian Participants Aged 2 Years and Older"; n 300; "Number of participants remaining recurrence-free during the 6 months post-treatment and have a negative blood smear at the Month 6 (end of study [EOS]) visit"; 2026-05-25
NCT07060404
"Postpartum 8-aminoquinoline Breast Milk Study"; n 60; "Pharmacokinetic: Distribution half -life"; 2027-05
recorded 2026-09-01 · last checked 2026-09-04
Q9
Which 42 trials of Primaquine posted no result?
Posted no result
42 of 42 completed trials
Registrations
NCT00000717, NCT00000640, NCT00959517, NCT00076323, NCT00158587 and NCT02394197, and 36 more
Completion dates
oldest 1991-11; newest 2024-03-31
Show the evidence
Trial
NCT00000717
1991-11
NCT00000640
1994-09
NCT00959517
2006-08
NCT00076323
2006-11
NCT00158587
2007-03
NCT02394197
2010-09
14 further recorded trials
NCT01500980
2012-11
NCT02789566
2012-12
NCT01205178
2013-04-01
NCT01365598
2013-05
NCT01878357
2013-11
NCT02143934
2014-05
NCT01076868
2014-09-02
NCT02090036
2014-11
NCT01680406
2014-12
NCT01708876
2014-12
NCT01780753
2014-12
NCT02691910
2015-09
NCT01716260
2015-10
NCT01838902
2015-10
Q10
At the median, Primaquine's trials enrolled 135 people — anything larger?
Median enrolment
135
Largest enrolment
39968
Registered trials counted
76
Q11
Primaquine and CYP2D6, P-GP and BCRP: shared by which compounds?
CYP2D6, P-GP and BCRP appear in Primaquine's recorded interaction sentences, 9 in all. openfda-label+europepmc · 2026-08-30
Effect of primaquine on the Pharmacokinetics of other drugs In vitro data suggest primaquine has the potential to inhibit CYP1A2 enzyme activity, but no or low potential to inhibit MAO-A, MAO-B, or CYP450 isoforms 2A6, 2C8, 2C9, 2C19, 2D6, 3A4 enzymes involved in drug biotransformation.
CYP2D6
pharmacokinetics
Experiments in mice indicate primaquine activity likely depends on the formation of CYP2D6 metabolite(s).
pharmacokinetics
CYP2D6 has variants that affect CYP2D6 metabolic function.
pharmacokinetics
CYP2D6 poor metabolizers are individuals with two nonfunctional alleles (e.g., CYP2D6*5/*5 ), and as a result have no CYP2D6 activity.
pharmacokinetics
CYP2D6 intermediate metabolizers are individuals with a combination of nonfunctional, reduced, or normal function alleles, and as a result have reduced CYP2D6 activity (e.g., CYP2D6*1/*5 , CYP2D6*4/*10 ).
pharmacokinetics
Individuals who are CYP2D6 intermediate or poor metabolizers exhibit a prolonged primaquine half-life and increased primaquine plasma concentrations when compared to individuals who are CYP2D6 normal metabolizers.
pharmacokinetics
CYP2D6 metabolizer status may be associated with variability in clinical response to Primaquine phosphate Tablets (see PRECAUTIONS ).
2 more recorded rows
CYP2D6clinical_pharmacology
In humans, primaquine phosphate activity is probably related to hydroxylated metabolites generated intrahepatically by CYP2D6.
CYP2D6pharmacokinetics
Pharmacogenomics Published clinical reports indicate that primaquine is a CYP2D6 substrate.
recorded 2026-08-30 · last checked 2026-09-04
Q12
Was Primaquine studied with fasting?
fasting is named in Primaquine's label sentences: "Three trials were designed as a single centre, randomized, single dose, open label, fasting, crossover bioequivalence studies comparing a new coated chloroquine tablet to the uncoated tablet, and 5 and 15 mg primaquine formulations to either an international reference product or the currently…" openfda-label+europepmc · 2026-08-30
1 recorded statement; fasting
Show the evidence
fasting
Three trials were designed as a single centre, randomized, single dose, open label, fasting, crossover bioequivalence studies comparing a new coated chloroquine tablet to the uncoated tablet, and 5 and 15 mg primaquine formulations to either an international reference product or the currently distributed tablets.
recorded 2026-08-30 · last checked 2026-09-04
Q13
What is recorded about Primaquine and autophagy?
"In this study, CP@ZIF-PQ/Ce6 NPs, a ZIF-90-based multimodal nanosystem loaded with copper peroxide (CP) nanoparticles, the autophagy inhibitor primaquine phosphate (PQ) and the photosensitizer Ce6, were developed." — where Primaquine and autophagy appear together. Europe PMC · pathway abstract search · 2026-07-30
autophagy, NAD+; PMID 42532321, 29582583, 3008737
Show the evidence
autophagy
PMID 42532321
"In this study, CP@ZIF-PQ/Ce6 NPs, a ZIF-90-based multimodal nanosystem loaded with copper peroxide (CP) nanoparticles, the autophagy inhibitor primaquine phosphate (PQ) and the photosensitizer Ce6, were developed."
PMID 29582583
"In this study, it is found that primaquine (PQ) suppresses autophagy flux at a late stage through the impeding fusion of the autophagosome with the lysosome to form an autophagolysosome, leading to cell apoptosis or necrosis."
NAD+
PMID 3008737
"Primaquine increases the NAD(P)H dependent oxygen consumption and hydroxyl radical generation by extracts of Trypanosoma cruzi, the causative agent of Chagas' disease."
PMID 3008737
"Spin-trapping studies show that hydroxyl radical yield is completely inhibited by catalase and slightly increased by SOD, indicating that radical generation is dependent on the pair primaquine-NAD(P)H and their interaction product, H2O2."
recorded 2026-07-30 · last checked 2026-09-04
Where it is registeredIdentifiers, relations and other names
ClinicalTrials.gov — US Government work · Europe PMC — metadata only, under the recorded legal gate · derived from this page's own recorded fields; no external licence · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
✗ 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: 9 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.