Should haloperidol be administered intravenously (IV) or intramuscularly (IM)?

Haloperidol Administration: IM vs IV Route

Intramuscular (IM) administration is the preferred parenteral route for haloperidol, as intravenous (IV) administration is not FDA-approved and carries significant cardiac risks. 1, 2, 3

Safety Considerations for Route Selection

• The FDA explicitly warns that "HALOPERIDOL INJECTION IS NOT APPROVED FOR INTRAVENOUS ADMINISTRATION" due to increased risk of QTc interval prolongation and Torsades de Pointes 2, 3
• The American Academy of Pediatrics recommends IM administration as the preferred parenteral route for antipsychotics in emergency department settings 1
• Cases of sudden death, QTc interval prolongation, and Torsades de Pointes have been reported with IV haloperidol administration 2, 3

Cardiac Risk Profile

• IV administration of haloperidol appears to be associated with a higher risk of QTc prolongation and Torsades de Pointes compared to other routes 2
• If haloperidol is administered intravenously (despite warnings), ECG monitoring is strongly recommended, especially for high-risk patients 1, 4
• Multiple studies have identified that patients receiving IV haloperidol frequently have baseline risk factors for QTc prolongation, with 85.7% of patients having at least one risk factor 5

Efficacy Considerations

• IM haloperidol (5 mg) has been shown to be effective in reducing agitation in approximately 30 minutes 6
• For rapid sedation in emergency settings, the American College of Emergency Physicians recommends using either a benzodiazepine or a conventional antipsychotic like haloperidol as effective monotherapy 7
• The combination of haloperidol (5 mg) with lorazepam (2 mg) administered intramuscularly may produce faster sedation than haloperidol monotherapy alone 6

Practical Administration Guidelines

• For adult patients with psychomotor agitation, the standard IM dose is 5 mg, which can be repeated based on clinical response 6
• When administering IM haloperidol, evaluate the response at 15-30 minutes; if there is inadequate response, an additional 5 mg dose may be considered 6
• For patients with severe agitation who don't cooperate, IM administration is preferred over oral routes 6

Special Considerations

• In patients at high risk for Torsades de Pointes, avoid using antipsychotics altogether if possible 7
• For patients with delirium not related to alcohol or benzodiazepine withdrawal, consider alternative agents such as dexmedetomidine 7
• If IV haloperidol is absolutely necessary (though not recommended), doses <2 mg may be safer without continuous ECG monitoring in patients without other risk factors 8
• For higher IV doses (>5 mg), ECG monitoring is strongly recommended, with telemetry for high-risk patients or those receiving cumulative doses of at least 100 mg 4

Management of Adverse Effects

• For acute dystonic reactions caused by haloperidol (regardless of route), administer anticholinergic medications such as benztropine 1-2 mg IM or diphenhydramine 25-50 mg 7
• Monitor for extrapyramidal symptoms, which occur in approximately 20% of patients receiving haloperidol 6