HALDOL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for HALDOL (HALDOL).
Haloperidol is a typical antipsychotic that blocks dopamine D2 receptors in the central nervous system, particularly in the mesolimbic and mesocortical pathways, reducing positive symptoms of schizophrenia. It also has moderate affinity for sigma receptors and weak affinity for serotonin 5-HT2, alpha-adrenergic, and histamine H1 receptors.
| Metabolism | Extensively metabolized in the liver primarily via CYP3A4 and CYP2D6, with minor contributions from other CYP enzymes. Major metabolites include reduced haloperidol (via ketoreduction) and other inactive or minimally active compounds. |
| Excretion | Renal (approximately 40%, with 1% unchanged; remainder as metabolites) and fecal (approximately 60%, primarily via bile). |
| Half-life | Terminal elimination half-life is approximately 21 hours (range 12–37 hours). Extended half-life in chronic administration supports once-daily dosing; dose adjustments required in hepatic impairment. |
| Protein binding | 92% bound primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Vd approximately 17 L/kg (range 10–22 L/kg). Large Vd indicates extensive tissue distribution, particularly to brain and adipose tissue. |
| Bioavailability | Oral: approximately 60–65% (first-pass metabolism); IM: 100%. |
| Onset of Action | Oral: 30–60 minutes (IM: 15–30 minutes; IV: 2–5 minutes). |
| Duration of Action | Oral: 12–24 hours (IM: 12–24 hours; IV: 4–8 hours). Clinical effects persist beyond plasma half-life due to redistribution and sustained receptor binding. |
| Molecular Weight | 375.9 |
| Action Class | Typical Antipsychotics |
| Brand Substitutes | Larenase 5mg Tablet, Hapdol 5mg Tablet, Zeedol 5mg Tablet, Helinase 5mg Tablet, Halodyl 5mg Tablet, Helinase 10mg Tablet, Zeedol 10mg Tablet, Halodyl 10mg Tablet, Halopace 10mg Tablet, Hpl 10mg Tablet |
Initial: 1-5 mg PO/IM twice daily; titrate up to 5-10 mg/day. Acute agitation: 5-10 mg IM every 1-8 hours. Maintenance: 5-10 mg/day PO/IM. Maximum: 100 mg/day.
| Dosage form | CONCENTRATE |
| Renal impairment | No dose adjustment required for mild-to-moderate renal impairment. For severe impairment (GFR <10 mL/min), use with caution and consider 50% dose reduction. |
| Liver impairment | Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 30-50%. Child-Pugh Class C: avoid use or reduce to 25% of usual dose. |
| Pediatric use | 3-6 years: 0.01-0.03 mg/kg/day PO divided twice daily; 6-12 years: 0.02-0.05 mg/kg/day PO divided twice daily; >12 years: 0.5-5 mg/day PO divided twice daily. IM: 1-5 mg IM every 4-8 hours as needed. |
| Geriatric use | Initial dose: 0.5-2 mg PO/IM daily; maximum 5 mg/day. Increase slowly by 0.5-1 mg every 5-7 days. Monitor for extrapyramidal symptoms and QT prolongation. |
| 1st trimester | Avoid unless essential; risk of fetal malformations (e.g., limb defects) based on some studies; known risk of extrapyramidal symptoms in neonates. |
| 2nd trimester | Use only if benefit outweighs risk; potential for fetal neurobehavioral effects. |
| 3rd trimester | Avoid near term; risk of neonatal extrapyramidal symptoms, withdrawal, and sedation; use only if clearly needed. |
Clinical note
Comprehensive clinical and safety monograph for HALDOL (HALDOL).
| Placental transfer | Haloperidol crosses the placenta readily, with cord blood concentrations approximately 40-80% of maternal serum levels. |
| Breastfeeding | Haloperidol is excreted into breast milk in low concentrations (estimated infant dose 0.5-2% of maternal weight-adjusted dose). Cases of infant drowsiness, developmental delay, and extrapyramidal symptoms have been reported. Monitor infant for sedation, poor feeding, and abnormal movements. Generally considered compatible with breastfeeding if benefit outweighs risk, but caution advised, especially with high maternal doses. |
■ FDA Black Box Warning
WARNING: Increased mortality in elderly patients with dementia-related psychosis. Haloperidol is not approved for the treatment of dementia-related psychosis. Also, QT interval prolongation and risk of sudden death, especially with high doses or intravenous administration.
| Serious Effects |
ComaSevere CNS depressionParkinson's diseaseKnown hypersensitivity to haloperidol or any componentConcurrent treatment with QT-prolonging drugs (if known risk of torsades)Clinically significant cardiac disorders (e.g., recent MI, uncompensated heart failure)
| Precautions | Increased mortality in elderly patients with dementia-related psychosis, QT prolongation and risk of torsade de pointes, Neuroleptic malignant syndrome (NMS), Tardive dyskinesia, Extrapyramidal symptoms (EPS), Seizures, Hyperprolactinemia, Leukopenia/neutropenia/agranulocytosis, Cognitive and motor impairment, Dysphagia and aspiration |
| Food/Dietary | Avoid alcohol and grapefruit juice. Haloperidol may interfere with electrolyte balance; avoid excessive caffeine intake. Maintain adequate hydration and a diet rich in potassium and magnesium to reduce QT prolongation risk. No specific food restrictions otherwise, but caution with tyramine-containing foods if used with MAOIs. |
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| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | First trimester: Increased risk of congenital malformations, particularly limb defects, with first-trimester exposure. Second and third trimesters: Risk of extrapyramidal symptoms and withdrawal in neonates (e.g., agitation, hypertonia, tremors). Overall, benefits may outweigh risks in severe psychiatric conditions. |
| Fetal Monitoring | Maternal: Monitor for extrapyramidal symptoms, blood pressure, ECG (QTc prolongation), and metabolic parameters (glucose, lipids). Fetal/neonatal: Monitor for extrapyramidal symptoms, sedation, and withdrawal post-delivery. Consider fetal ultrasound for anomaly detection if first-trimester exposure. |
| Fertility Effects | Haloperidol may elevate prolactin levels, leading to menstrual irregularities, galactorrhea, and potential reversible infertility. No known direct effect on gametogenesis. |
| Clinical Pearls | Haldol (haloperidol) is a high-potency typical antipsychotic. Monitor for extrapyramidal symptoms (EPS), especially acute dystonia, akathisia, and parkinsonism. Avoid use in patients with Parkinson's disease or Lewy body dementia due to increased sensitivity. QT interval prolongation risk: obtain baseline ECG and monitor electrolytes; avoid concomitant use with other QT-prolonging drugs. IM formulation can be used for acute agitation but may cause significant hypotension. Tardive dyskinesia risk is higher with long-term use; consider periodic dyskinesia screening. Neuroleptic malignant syndrome (NMS) is rare but life-threatening; discontinue immediately if fever, rigidity, or elevated CK occur. |
| Patient Advice | Do not stop taking this medication abruptly without consulting your doctor. · Avoid alcohol and grapefruit juice while taking haloperidol. · Report any involuntary muscle movements, stiffness, or restlessness to your doctor immediately. · Haloperidol may cause drowsiness; do not drive or operate heavy machinery until you know how it affects you. · Drink plenty of fluids and avoid overheating to reduce the risk of heat stroke. · Contact your doctor if you experience palpitations, fainting, or prolonged QT symptoms (chest pain, dizziness). · Avoid sudden position changes to prevent orthostatic hypotension. · Store medication at room temperature away from light and moisture. |