Causality assessment · Causality: well established

Haloperidol and QT prolongation / torsades: is the FAERS signal real?

n=653 co-reports · PRR 16.0 · ROR 16.4

Haloperidol side-effect profile All assessments See in the full list

A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.

Causality: well established

Haloperidol ↔ QT prolongation / torsades

n=653 co-reports · PRR 16.0 · ROR 16.4

Haloperidol, a first-generation antipsychotic widely used for agitation and delirium, prolongs the QT interval and carries a labelled warning for torsades de pointes, particularly with intravenous use or high doses. The risk is amplified by other QT-prolonging drugs and electrolyte disturbance, and it is why ECG monitoring is advised in at-risk patients. The 653 co-reports (PRR 16.0) reflect both the real effect and the drug's frequent use in acutely unwell patients.

Regulatory basis: haloperidol prescribing information (QT prolongation and torsades warning; ECG caution).

Bradford Hill viewpoint	Status	Note
Temporality (necessary)	met	QT prolongation is measured during therapy and resolves after withdrawal
Strength	met	PRR 16 on a moderate co-report count
Consistency	met	Reproduced across ECG studies and trials
Specificity	partial	A recognised antipsychotic effect, strongest for some agents such as haloperidol
Biological gradient	partial	Worse with dose, IV use, and electrolyte disturbance
Plausibility	met	hERG-channel blockade delays cardiac repolarisation
Coherence	met	Coheres with the labelled ECG-monitoring advice
Experiment	met	A randomized ICU trial recorded torsades by arm (rarely, but on haloperidol)
Analogy	met	Analogous to QT risk with other antipsychotics (thioridazine, ziprasidone)

This page's own qualitative read, not an automated/citation-gated assessment.

✓ Trial evidence found — The Modifying the Impact of ICU-Associated Neurological Dysfunction-USA (MIND-USA) Study (NCT01211522), N=566

Term (as recorded)	Haloperidol (n=192)	Ziprasidone (n=190)	Placebo (n=184)
Torsades de pointes — Cardiac disorders	2	1	1

In this randomized ICU trial, torsades de pointes occurred in 2 of 192 patients on haloperidol (about 1%), versus 1 on ziprasidone and 1 on placebo — a low absolute rate that nonetheless shows the event is recorded on haloperidol, which itself carries a QT/torsades warning. View on ClinicalTrials.gov →