What is the maximum dose of haloperidol (Haldol) given intramuscularly (IM) within 24 hours?

Maximum Dose of Haloperidol 5mg IM Within 24 Hours

The maximum dose of haloperidol IM is 20 mg per day according to FDA labeling, which means you can administer up to four doses of 5 mg IM within 24 hours. 1

FDA-Approved Maximum Dosing

• The FDA label explicitly states: "The maximum dose is 20 mg/day" for intramuscular haloperidol administration 1
• Initial IM doses of 2-5 mg are recommended for prompt control of acute agitation in schizophrenia 1
• Subsequent doses may be administered as often as every hour, though 4-8 hour intervals are typically satisfactory 1

Guideline-Based Dosing Recommendations

For adults with acute agitation:

• Standard initial dose: 5-10 mg IM 2, 3
• May repeat every 20-30 minutes until tranquilization is achieved 2, 3
• Maximum daily limit: 40 mg for adolescents and adults according to American Academy of Pediatrics guidelines 3

Important discrepancy to note: The American Academy of Pediatrics recommends a maximum of 40 mg daily 3, which exceeds the FDA-approved maximum of 20 mg/day 1. In clinical practice, you should prioritize the FDA labeling limit of 20 mg/day for standard use.

Practical Dosing Algorithm for 5mg IM Doses

If using 5 mg IM doses specifically:

1. First dose: 5 mg IM initially 1
2. Subsequent doses: May repeat 5 mg every 4-8 hours as needed 1
3. Maximum frequency: Can be given as often as every hour if clinically necessary 1
4. Daily maximum: Do not exceed 20 mg total (4 doses of 5 mg) in 24 hours per FDA guidelines 1

Special Population Considerations

Elderly or debilitated patients:

• Require lower doses than the standard maximum 1
• Initial doses of 0.5-1 mg are recommended 4
• Low-dose haloperidol (≤0.5 mg) showed similar efficacy to higher doses with better safety profile 4

Pediatric patients:

• Dose: 0.05-0.15 mg/kg IM (maximum 5 mg per dose) 3
• May repeat hourly as needed 3
• Maximum daily dose for children: 30 mg 3

Critical Safety Monitoring

With repeated dosing, monitor for:

• Extrapyramidal symptoms (dystonia, akathisia) - more common at higher cumulative doses 2, 3
• QTc prolongation - risk increases above 7.5 mg/day 3
• Hypotension, particularly in unstable patients 2
• Respiratory depression when combined with benzodiazepines 2

Common Clinical Pitfall

The 40 mg maximum cited in pediatric emergency guidelines 3 should NOT be applied routinely - this represents an upper limit for severe refractory agitation in controlled settings and exceeds FDA-approved dosing. For standard practice with 5 mg IM doses, adhere to the FDA maximum of 20 mg/24 hours (4 doses) 1.