Haloperidol Dosage for Adults
For adults with acute psychosis or agitation, the recommended initial haloperidol dosage is 2.5-5 mg intramuscularly, which can be repeated every 4-6 hours as needed. 1 For oral administration, the FDA recommends 0.5-2 mg two or three times daily for moderate symptomatology and 3-5 mg two or three times daily for severe symptomatology. 2
Dosing Guidelines by Clinical Scenario
Acute Agitation/Psychosis
- Initial IM dose: 2.5-5 mg 1
- Frequency: Can be repeated every 4-6 hours as needed 1
- Combination therapy: Consider combining with lorazepam 2 mg for more rapid sedation 1
- Maximum daily dose: Up to 100 mg may be necessary in severely resistant cases, though this is uncommon 2
Oral Administration for Ongoing Management
- Moderate symptoms: 0.5-2 mg 2-3 times daily (1-6 mg/day) 2
- Severe symptoms: 3-5 mg 2-3 times daily (6-15 mg/day) 2
- First-episode psychosis: Lower doses are often effective, with a maximum daily dose of 4-6 mg recommended 1
- Research shows many first-episode patients respond to just 2 mg daily 3
Special Populations
- Geriatric or debilitated patients: 0.5-2 mg 2-3 times daily 2
- Lower doses (≤0.5 mg) for injectable haloperidol have shown similar efficacy to higher doses in older patients 4
- Children (3-12 years): Not the focus of this response, but dosing starts at 0.5 mg/day 2
Important Clinical Considerations
Dose Titration
- Allow 14-21 days before increasing doses to evaluate efficacy 1
- Optimal plasma levels are 5.5-14.4 ng/ml; levels above 14.4 ng/ml may worsen negative symptoms 1
- Research indicates that doses higher than 10 mg/day provide no additional benefit for most patients with schizophrenia 5
Side Effect Monitoring
- Extrapyramidal symptoms (EPS): Dose-dependent and more common at doses above 7.5 mg/day 1
- QTc prolongation: Monitor ECG in high-risk patients, especially when combining with other QTc-prolonging medications 1
- Sedation: Higher risk with doses exceeding 1 mg in 24 hours, particularly in elderly patients 6
Common Pitfalls to Avoid
- Overdosing: Higher than recommended doses do not improve outcomes but increase side effects, especially in older adults 6
- Inadequate trial period: Allow sufficient time (2-4 weeks) at the lower effective dose before concluding lack of efficacy 1
- Ignoring first-episode sensitivity: First-episode patients often respond to much lower doses (2 mg daily) 3
- Overlooking combination therapy: The combination of haloperidol with lorazepam is more effective than either medication alone for acute agitation 1
While some case reports document the use of very high doses (>100 mg/day IV) in specific cardiac patients with severe agitation 7, these are exceptional cases and not standard practice. For most patients, moderate doses as outlined above are effective while minimizing side effects.