This page shows what was measured, who it was measured in, and what that does not settle.
What Droperidol does in the body
Droperidol blocks dopamine receptors, which stops nausea at the brain's vomiting trigger zone and calms agitation.
Like many drugs, it also has some effect on a potassium channel the heart uses to reset after each beat, which can lengthen the QT interval on an electrocardiogram. The question that has never been settled is whether the amount it does this at the doses actually used is enough to matter, and the evidence gathered since the warning suggests it mostly is not.
Why people take it. Used by injection for severe nausea, agitation or migraine.
What happened in people
One dangerous rhythm occurred among more than 16,000 emergency-department doses, in a person with several other risks.
✓ Reviewed first-read answer
Where this came from
A person wrote this and a reviewer approved it against this exact record. It carries no effect size.
A reviewer approved this against this record. The reviewed-claim record carrying the exact population and effect size does not exist yet.
No source is stored against this line.
The limit that matters most
Evidence from one small emergency dose cannot settle the risk of larger psychiatric doses.
Where it acts
Chemoreceptor trigger zone and mesolimbic dopamine pathways; the alleged toxicity site is ventricular repolarisation
Kind of result
The kind of result is not recorded
Supervision
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · O9U0F09D5X · read 2026-08-29
Where each sentence above came from
A person wrote this explanation into the record, with the studies named in the path below.
A reviewer approved this sentence against this exact record and its sources.
The limit a reviewer approved as the one that matters most here.
The four opening statements run to 107 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.
Absolute difference
An absolute difference is how many more people in a hundred were affected.
A picture of it, and where the picture fails
It is like counting heads in two rooms of a hundred.
Where that stops being true. Heads are easy to count. Study results carry a margin of error too.
What people get wrong. It is confused with a percentage change, which can look far larger.
The arithmetic difference in event rates between arms.
Confidence interval
A confidence interval is the range the true answer is likely to sit in.
A picture of it, and where the picture fails
It is like a weather forecast giving a range rather than one number.
Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.
What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.
An interval estimate that would contain the true parameter in a stated proportion of repeated studies.
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.
Strength of evidence for a causal association between therapeutic droperidol administration and life-threatening cardiac events
✗ The study did not show it
Who was studied
Evidence-based review of droperidol, QT prolongation and sudden death (Kao et al.)
How many people
11
Study design
Systematic evidence review applying evidence-based medicine and Hill's criteria
Compared against
Not recorded for this study
Kind of result
Measured performance
What was found
Three clinical studies, one abstract, seven case reports and MedWatch surveillance data reviewed; evidence judged not convincing for causation at therapeutic doses
Repeated elsewhere
Partially Replicated
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. A review cannot generate evidence that does not exist. The authors explicitly call for ongoing safety monitoring and more definitive study rather than treating the question as closed.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Intravenous or intramuscular injection
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Incidence of QT prolongation and torsades de pointes in emergency department patients receiving droperidol
✓ The study showed what it set out to show
Who was studied
Emergency department droperidol QT and torsades incidence study
How many people
16546
Study design
Retrospective cohort with electronic health record dose denominator, 1997-2001
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Torsades de pointes 1 in 16,546 doses (0.006 per cent, 95% CI 0.00015 to 0.03367); mean QTc 424.3 to 427.6 ms in non-critical and 435.7 to 435.8 ms in critically ill paired recordings; 13 of 337 nomogram plots above the at-risk line
Repeated elsewhere
Partially Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Retrospective, single-centre, and electrocardiograms were available for only a minority of dosed patients, so paired comparisons rest on 170 and 114 patients respectively rather than on the full cohort.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Intravenous or intramuscular injection
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Predictors of QTc above 456 ms among psychiatric inpatients and community patients
✓ The study showed what it set out to show
Who was studied
QTc prevalence study in psychiatric patients (Reilly et al.)
How many people
596
Study design
Cross-sectional prevalence study with healthy reference group
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
Droperidol odds ratio 6.7 (95% CI 1.8 to 24.8), the highest individual drug estimate; thioridazine 5.4 (2.0 to 13.7); very high antipsychotic dose 8.2 (1.5 to 43.6)
Repeated elsewhere
Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. The population is psychiatric patients on antipsychotic regimens, not emergency patients receiving a single low intravenous dose, and the confidence interval spans an order of magnitude.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Intravenous or intramuscular injection
Interval reported. 95% CI 1
Written into the record, not signed off as a reviewed claim.
RNAWiki holds 3 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 it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Start
Droperidol
What a person takes: Intravenous or intramuscular injection.
The measurement behind this step
Parenteral droperidol, typically 0.625 to 1.25 mg intravenously for postoperative nausea and vomiting and 2.5 to 5 mg for acute agitation, with onset within minutes and duration of several hours. Hepatically metabolised with a terminal half-life of around two hours.
Getting in
A small intravenous or intramuscular dose
Injected, usually into a vein, at doses well under a milligram for nausea and a few milligrams for agitation.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Parenteral droperidol, typically 0.625 to 1.25 mg intravenously for postoperative nausea and 2.5 to 5 mg for acute agitation. Onset within minutes and duration of several hours, which is why it displaced slower alternatives in emergency use.
Reaches the chemoreceptor trigger zone and limbic pathways
It reaches the brain region that triggers vomiting and the circuits involved in agitation.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Distributes rapidly to the chemoreceptor trigger zone in the area postrema, which lies outside the blood-brain barrier, and to mesolimbic dopamine pathways. Hepatic metabolism with a terminal half-life of around two hours.
Blocks dopamine D2 receptors, and inhibits hERG in vitro
It blocks dopamine receptors, which is how it works. In laboratory tests it also blocks a heart potassium channel, and how much that matters at real doses is the disputed question.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Potent D2 antagonism at the chemoreceptor trigger zone and in limbic pathways, with moderate alpha-1 adrenergic blockade producing hypotension. In vitro hERG inhibition is documented; the contested issue is the margin between the blocking concentration and the free plasma concentration at clinical doses.
Nausea and agitation resolve; the QT interval moves slightly
Vomiting stops and agitation settles within minutes. On average the QT interval lengthens by a few milliseconds.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
D2 blockade at the area postrema suppresses emesis and limbic blockade produces sedation. Measured mean QTc change was 424.3 to 427.6 ms in non-critical patients and 435.7 to 435.8 ms in critically ill patients — 3.3 ms and essentially zero respectively.
Effective in minutes; one torsades case in 16,546 doses
It works quickly and reliably. Across more than sixteen thousand doses, one patient developed the arrhythmia the warning is about, and that patient had several other risk factors.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Measured: torsades de pointes in 1 of 16,546 doses, 0.006 per cent (95% CI 0.00015 to 0.03367 per cent), in a patient with multiple risk factors who tolerated re-challenge. Measured: odds ratio 6.7 (95% CI 1.8 to 24.8) for QTc above 456 ms in a psychiatric population on antipsychotic doses.
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 5 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
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.
Patients in emergency departments and operating theatres. Droperidol returned to wide United States availability in early 2019 after a six-year hiatus and is recorded in Drugs@FDA as Prescription under generic applications.
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: “The safety of droperidol in children younger than two years of age has not been established.”
US prescribing information · 147e033d-d997-4ef6-8bb5-a9ba372590b2 · read 2026-08-30
On people who are pregnant, the label states: “Droperidol administered intravenously has been shown to cause a slight increase in mortality of the newborn rat at 4.4 times the upper human dose.”
US prescribing information · 147e033d-d997-4ef6-8bb5-a9ba372590b2 · read 2026-08-30
On people who are breastfeeding, the label states: “It is not known whether droperidol is excreted in human milk.”
US prescribing information · 147e033d-d997-4ef6-8bb5-a9ba372590b2 · read 2026-08-30
Where the result stopped carrying
A boxed warning was added in December 2001 on evidence a subsequent review traced to post-marketing surveillance rather than the peer-reviewed literature
Use collapsed and United States supply lapsed for six years, functioning as a de facto withdrawal
The original application, NDA 016796 for INAPSINE, is recorded in Drugs@FDA as Discontinued
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 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 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
Withdrawn
❝ 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
Intravenous or intramuscular injection
✎ 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
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Suppression classes recorded: S6, S8.
No source is stored against this line.
What is in the pack
5 to 5 mg for acute agitation, with onset within minutes and duration of several hours. Hepatically metabolised with a terminal half-life of around two hours.
✎ 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◇Read from sources, not yet reviewed
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.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
The boxed warning added in December 2001 concerns QT prolongation and torsades de pointes. The measured effect at emergency-department doses is small — mean QTc rising from 424.3 to 427.6 ms in non-critical patients and unchanged in the critically ill — and the measured event rate is one case of torsades de pointes in 16,546 doses, in a patient with multiple risk factors who tolerated re-challenge. Independent electrocardiographic surveys in psychiatric populations on antipsychotic doses give droperidol an odds ratio of 6.7 for abnormal QTc, the highest of the drugs examined. Other effects are dose-related sedation, hypotension from alpha-1 blockade, akathisia and dystonic reactions. Caution is warranted in known long QT syndrome, electrolyte disturbance and concurrent QT-prolonging drugs.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
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
Intravenous or intramuscular injection
✎ 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
5 to 5 mg for acute agitation, with onset within minutes and duration of several hours. Hepatically metabolised with a terminal half-life of around two hours.
✎ 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 which forms are sold and how they compare.
No source is stored against this line.
What is recorded as being sold
4 products list this as an active ingredient in the United States drug directory. 4 of them contain it and nothing else.
FDA National Drug Code directory · 0143-9514 · read 2026-08-29
They are sold as injection, solution and powder, taken intramuscular and intravenous.
FDA National Drug Code directory · 0143-9514 · read 2026-08-29
The regulator's established pharmacologic class for it is dopamine d2 antagonists [moa] and dopamine-2 receptor antagonist [epc].
FDA National Drug Code directory · 0143-9514 · read 2026-08-29
2 published labels name it as an active ingredient. 2 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 147e033d-d997-4ef6-8bb5-a9ba372590b2 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 147e033d-d997-4ef6-8bb5-a9ba372590b2 · read 2026-08-29
Droperidol is intramuscular at HOW SUPPLIED Droperidol Injection USP, (2.5 mg/mL) is available as: Product No. Strength Size How Packaged NDC 0517-9702-25 5 mg/2 mL 2 mL Single Dose Vial Boxes of 25 Store at 20° to 25°C (68° to 77°F); excursions perm…, recorded as fda label in effect 2023-03-20 in the United States.
US prescribing information · 147e033d-d997-4ef6-8bb5-a9ba372590b2 · 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.
Self-experiment planning is not offered for a prescription or clinician-supervised medicine, withdrawn medicine. The questions below are for a clinician or pharmacist.
Questions worth asking
Which of the trials of Droperidol 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
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That QTc findings in psychiatric patients on antipsychotic doses predict risk from single low-dose intravenous antiemetic use
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the boxed warning reflects a demonstrated causal relationship at therapeutic doses; a formal review found the evidence unconvincing for causation
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the risk is unique to droperidol among its substitutes; ondansetron and haloperidol both prolong QT without a boxed warning
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
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.
How much did people take in the studies?
The sources RNAWiki checked hold nothing for this field.
Why it matters. A result belongs to an amount. Without the amount the result floats free.
What would answer it
A stored source that records 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 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 Droperidol 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.
Every line above can be traced to the study named beside it. Follow the link and read it.
The boxed warning came from surveillance reports, not the published literature
In plain words
A formal review found that the evidence behind the 2001 warning came from spontaneous adverse-event reports rather than from studies, and did not establish that therapeutic doses cause fatal arrhythmias.
What was measured
Not recorded
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
An evidence-based review examined the association between droperidol and QT prolongation or torsades de pointes, covering three clinical studies, one published abstract, seven case reports and available MedWatch post-marketing surveillance data. Applying evidence-based medicine criteria and Hill's criteria for causation, the authors concluded that the evidence is not convincing for a causal relationship between therapeutic droperidol administration and life-threatening cardiac events, and that the boxed warning appears to have originated from post-marketing surveillance data rather than from data reported in the peer-reviewed literature. They call for ongoing safety monitoring and more definitive study rather than dismissing the question.
Written into the record, not signed off as a reviewed claim
One torsades case in 16,546 doses, and a 3.3 millisecond mean QTc change
In plain words
Reviewing more than sixteen thousand doses given in an emergency department, one patient had the arrhythmia — and that patient had multiple other risk factors and tolerated a later re-challenge.
What was measured
Incidence of torsades de pointes per dose, and mean QTc change before and after droperidol
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Patients receiving droperidol at an urban Level I trauma centre from 1997 to 2001 were identified by electronic health record query and reviewed for cardiac arrest, with electrocardiographic data recorded for both critically ill and non-critical patients. Among non-critical patients, 15,374 received 18,020 doses and 2,431 had an electrocardiogram; in the 170 with recordings before and after droperidol, mean QTc was 424.3 ms (95% CI 419.7 to 428.9) before and 427.6 ms (424.3 to 430.9) after. Among 1,172 critically ill patients, 396 had an electrocardiogram, and in the 114 with paired recordings mean QTc was 435.7 ms before and 435.8 ms after. Of 337 electrocardiograms suitable for the QT nomogram, 13 (3.8 per cent) were above the at-risk line: 3 of 136 (2.2 per cent) before and 10 of 202 (4.9 per cent) after. A single case of torsades de pointes occurred, in a patient with multiple risk factors, and did not recur on droperidol re-challenge — an incidence of 1 in 16,546, or 0.006 per cent (95% CI 0.00015 to 0.03367 per cent).
Written into the record, not signed off as a reviewed claim
The independent prevalence study found droperidol the strongest QTc predictor
In plain words
The same electrocardiographic survey that condemned thioridazine gave droperidol an even higher odds ratio for a prolonged QT interval.
What was measured
Odds ratio 6.7 (95% CI 1.8 to 24.8) for QTc above 456 ms with droperidol
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
In a cross-sectional study of 495 psychiatric patients and 101 healthy reference individuals, with QTc measured by validated digitiser technique and predictors identified by logistic regression, droperidol carried an odds ratio of 6.7 (95% CI 1.8 to 24.8) for QTc above 456 ms — the highest of the individual drugs examined, above thioridazine at 5.4 (2.0 to 13.7) and tricyclic antidepressants at 4.4 (1.6 to 12.1). This is independent evidence that droperidol does prolong QTc, and it is the strongest measurement supporting the warning. Its limitations are equally clear: the confidence interval runs from 1.8 to 24.8, QTc is a predictive marker rather than an event, and the population is psychiatric inpatients on chronic antipsychotic regimens rather than emergency patients receiving a single low intravenous dose.
Written into the record, not signed off as a reviewed claim
The dose used matters, and the two evidence bases are about different doses
In plain words
The psychiatric evidence concerns patients on antipsychotic regimens; the emergency evidence concerns single small intravenous doses. Reading either as settling the other is the central error here.
What was measured
That QTc prolongation observed in psychiatric patients on antipsychotic doses predicts risk from single low-dose intravenous antiemetic administration
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Droperidol is used at antiemetic doses well under a milligram to a few milligrams intravenously in the emergency and perioperative settings, and was historically used at far higher doses as a neuroleptic. The prevalence study that produced the 6.7 odds ratio examined psychiatric patients in inpatient and community settings, where antipsychotic dose was itself a strong independent predictor — high dose 5.3 and very high dose 8.2. The emergency department series measured 18,020 doses in ordinary clinical use and found a mean QTc change of 3.3 ms and one arrhythmia in 16,546. Both are correct about their own population. A boxed warning that does not distinguish them treats a dose-dependent effect as though dose were irrelevant, which is what the emergency medicine literature has objected to for two decades.
Written into the record, not signed off as a reviewed claim
Use collapsed, supply lapsed for six years, and the drug came back anyway
In plain words
After the warning, prescribing fell away and the drug became unavailable in the United States for six years. It returned in 2019, with the warning still on the label.
What was measured
Not recorded
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
Following the December 2001 boxed warning, droperidol use declined sharply and United States supply lapsed. It became widely available again in early 2019 after a six-year hiatus, with the boxed warning unchanged. Drugs@FDA records the original NDA 016796 for INAPSINE as Discontinued, with generic droperidol applications from Hikma and American Regent in Prescription status. So a warning removed a drug from practice without removing it from the market, supply followed demand out and then back in, and the regulatory text that started the sequence was never revisited. That is a distinct failure mode from anything else in this file: not withdrawal, not restriction, but a label change that functioned as a de facto withdrawal for most of two decades.
Written into the record, not signed off as a reviewed claim
The substitutes prolong QT too, and carry no boxed warning
In plain words
Ondansetron and haloperidol, the drugs that replaced droperidol, both lengthen the QT interval themselves. Neither has a boxed warning for it.
What was measured
That the boxed warning reflects a QT risk unique to droperidol among the drugs used for the same indications
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Ondansetron has a documented dose-related QT effect substantial enough that single intravenous doses were subsequently restricted, and haloperidol — droperidol's closest structural relative — prolongs QT particularly by the intravenous route. Neither carries a boxed warning for it. If the harm attributed to droperidol were a class or mechanism property at the doses used, the same action would be expected for its replacements. That it was not is not proof the warning was wrong: regulatory actions depend on the evidence presented at a particular time, and consistency across drugs is not itself an evidentiary standard. It is, however, why the emergency medicine literature reads the warning as disproportionate rather than as simply incorrect.
Written into the record, not signed off as a reviewed claim
The measurement method changes the answer, and the nomogram was used
In plain words
The standard formula for correcting QT for heart rate exaggerates the interval in patients with fast heart rates — exactly the patients who get this drug. The emergency study plotted the raw values instead.
What was measured
Proportion of electrocardiograms above the QT nomogram at-risk line, before and after droperidol
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Bazett's correction, which the study reports alongside its nomogram analysis, systematically overestimates the corrected interval at high heart rates. Agitated, febrile, intoxicated or hypovolaemic emergency patients are tachycardic before any drug is given, so a Bazett-corrected QTc in that population is biased upward by the patient's state rather than by the drug. The study addressed this by plotting QT against RR interval on the QT nomogram for the 337 electrocardiograms suitable for it, finding 13 (3.8 per cent) above the at-risk line — 3 of 136 before dosing and 10 of 202 after. Reporting the underlying measurement rather than only the corrected one is what makes a QT study interpretable in a tachycardic population, and it is a methodological point that applies to every QT claim on this page.
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What is not here
7 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.
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.
What changed on this page — found nothing in the sources checked.
The record as stored
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The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
A butyrophenone given a boxed warning in December 2001 for QT prolongation and torsades de pointes, which an evidence-based review found unconvincing for a causal relationship at therapeutic doses and which a later study of 16,546 emergency department doses put at one case of torsades de pointes — 0.006 per cent — with mean QTc rising from 424.3 to 427.6 milliseconds.
"lack of enrollment/drug shortages"; 3 of 17 registered studies
Show the evidence
Trial
NCT01406860
terminated; "lack of enrollment/drug shortages"
NCT05065567
terminated; "Lost too many patients to follow up, unable to enroll enough patients"
NCT05401058
terminated; "The trial was terminated on the independent DSMB's recommendation after an interim analysis showed no evidence of benefit and a numerically higher incidence of postoperative delirium in the droperidol group, raising a potential safety…"
recorded 2026-09-01 · last checked 2026-09-04
Q6
Which 6 trials of Droperidol posted no result?
Posted no result
6 of 6 completed trials
Registrations
NCT01679093, NCT00702442, NCT02744495, NCT02600741, NCT03677323 and NCT04411069
Completion dates
oldest 2011-06; newest 2021-03-20
Show the evidence
Trial
NCT01679093
2011-06
NCT00702442
2011-07
NCT02744495
2016-12
NCT02600741
2018-07-05
NCT03677323
2019-02-21
NCT04411069
2021-03-20
Q7
At the median, Droperidol's trials enrolled 104 people — anything larger?
Median enrolment
104
Largest enrolment
27034
Registered trials counted
17
Q8
What do 297 spontaneous reports say about Droperidol — 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.
Droperidol appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 297 reaction mentions were counted: drug hypersensitivity 53; anaphylactic shock 39; hypotension 36; tachycardia 32. FAERS via Open Targets · CHEMBL1108 · 2026-06-24
Show the evidence
drug hypersensitivity
53
anaphylactic shock
39
hypotension
36
tachycardia
32
renal failure acute
28
anaphylactic reaction
26
4 more recorded rows
acute kidney injury
25
oliguria
22
dystonia
19
electrocardiogram qt prolonged
17
recorded 2026-06-24 · last checked 2026-09-04
Q9
Which 10 reactions does Droperidol's label not list?
ChEMBL 37 — CC BY-SA 3.0 Unported · 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
✗ 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
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