Publications

Published: June 2005
MARC prescriber advice

Thioridazine Prescribing Reminder

Prescriber Update 26(1): 9
June 2005

Medsafe Pharmacovigilance Team

Prescribers are reminded that thioridazine is a third-line antipsychotic agent and should only be prescribed in patients for whom the therapeutic benefits clearly outweigh the risk of arrhythmia from QT-prolongation.

Thioridazine (Aldazine®, Melleril®*) increases the risk of arrhythmia from QT-prolongation.  Consequently, the Medicines Adverse Reactions Committee (MARC) recommended changes to how thioridazine is prescribed in New Zealand.  The following advice was issued in June 2001 (see www.medsafe.govt.nz/profs/PUarticles/thioridazine.htm), which the MARC would like to reiterate.

Thioridazine is contraindicated in the following circumstances, all of which are risk factors for arrhythmia:

Thioridazine should be initiated only by a specialist and only as third-line therapy.  In addition, the following precautions should be observed for new patients:

For all patients currently taking thioridazine:

Any children taking thioridazine should also have their therapy reviewed by a specialist.  If thioridazine discontinuation is necessary, gradually reduce the dose over a period of one month and concurrently introduce alternative medication.  Specialist supervision may be advisable for the withdrawal process.

* Novartis has advised that from 1 July 2005 supplies of Melleril will no longer be available.

Competing interests (authors): none declared.