Published: December 2012
Prescriber Update 33(4): 36
Healthcare professionals are advised that, due to the risk of life-threatening arrhythmia, the dosing recommendations for immediate release haloperidol have changed. The initial starting dose for oral and intravenous (IV) administration is now 0.5mg and the maximum recommended daily dose is now 30mg. This maximum dose should only be used in exceptional circumstances.
Medsafe and the Medicines Adverse Reactions Committee (MARC) have reviewed the available evidence regarding effective and safe dosing levels. The evidence suggests that doses greater than 10mg per day are unlikely to provide further efficacy, yet may lead to increased adverse events. It is possible that some individuals may benefit from higher doses of haloperidol (greater than 10mg per day). However, the research review was unable to characterise patients who may benefit from higher doses.
Information on adverse events associated with the route of administration was also considered. The evidence reviewed suggests that IV administration of haloperidol is associated with an increased risk of QT prolongation and Torsades de Pointes (TdP).
Prescribers should carefully consider the risk of QT prolongation and TdP when deciding on administration route for patients. Patients with multiple risk factors for QT prolongation should be monitored carefully (including ECGs and potassium levels), particularly during the initial phase of treatment. Further information on risk factors can be found in Table 1 of the article 'Do all antidepressants cause QT prolongation?' in this edition of Prescriber Update1.
When prescribing haloperidol, prescribers should consider that: