Haloperidol and QTc prolongation

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The use of haloperidol is contra-indicated in combination with other drugs known to prolong the QTc interval.

Details of drugs that are known to be associated with QT prolongation can be found via crediblemeds or Stockley’s Drug Interactions.

Clinicians are advised to take the following actions

1. Review the medication of all patients prescribed haloperidol on a regular basis. If treatment with haloperidol is essential, where possible discontinue any other medicines known to prolong QTc.

2. Review the medication of all patients prescribed haloperidol on an ‘as required’ basis for the management of disturbed behaviour. If intermittent use of an antipsychotic for this purpose is still required discontinue haloperidol and prescribe an alternative antipsychotic.

3. If on review, the use of haloperidol in combination with other drugs is clinically appropriate and therefore unavoidable ensure that the rationale for treatment and relevant patient consents are obtained and documented.

4. Do not prescribe haloperidol to patients whose cardiac status is unknown or unstable.



Pre-treatment Ongoing treatment


Correct any electrolyte disturbances* (e.g. hypokalaemia, hypocalcaemia and hypomagnesaemia)

Annual ECG (increased frequency maybe required on a case by case basis)

If cardiovascular symptoms suggestive of arrhythmias develop, such as palpitations, dizziness, syncope or seizures during treatment, cardiac evaluation including an ECG should be undertaken to exclude a possible malignant cardiac arrhythmia.


If the QTc interval is >500 milliseconds treatment should be stopped.

*If circumstances make this impractical either do not use haloperidol or if use is unavoidable a clear justification must be recorded in the chronological account of care.

Haloperidol for regular use

If a patient is on regular haloperidol and a contraindicated medication known to prolong QTc interval:

• Review ongoing need for haloperidol or concurrent contraindicated medication and consider changing if appropriate

• If combination cannot be avoided:

  • Assess risk factors for QTc prolongation
  • Consider increased monitoring and do an ECG and biochemical monitoring if not recently performed
  • Obtain and Document consent. If informed consent is not possible, a local second opinion should be sought initially and after two months a DMP second opinion obtained if necessary.
  • Ensure the rationale for continuing the combination is clearly documented within the individual’s chronological account of care.
  • Ensure ongoing review of combination, including review of physical risk factors and close monitoring of ECG and biochemical parameters.
Haloperdol for when required use

A patient who requires ‘as required’ psychotropic medication and is already on a medication that would be contraindicated with haloperidol e.g. a regular antipsychotic:

• Consider all options available for managing for acute psychiatric disturbance including non- medication options.

• Avoid the use of ‘as required’ haloperidol in individuals who are already receiving medications known to prolong QTc interval.

• Where ‘as required’ medication is deemed to be appropriate, develop a clear individualised treatment plan which incorporates the use of oral and if appropriate, IM ‘as required’ medication. For alternative options see full guideline

• If the use of haloperidol is clinically appropriate e.g. due to previous good response, or because alternatives are not appropriate, the following advice should be adhered to:

  • Assess risk factors for QTc prolongation
  • Consider increased monitoring and do an ECG and biochemical monitoring if not recently performed
Editorial Information

Last reviewed: 07 April 2020

Next review: 01 April 2023

Author(s): PMG-MH

Version: 1

Approved By: PMG-MH

Reviewer Name(s): Andrew Walker, Suzanne Burke