HALOPERIDOL LACTATE
Clinical safety rating: safe
CNS depressants may enhance sedative effects Can cause extrapyramidal symptoms and QT prolongation.
Haloperidol lactate is a typical antipsychotic that exerts its effects primarily by blocking dopamine D2 receptors in the brain, particularly in the mesolimbic and mesocortical pathways. It also has antagonistic activity at alpha-1 adrenergic receptors and limited affinity for serotonin receptors.
| Metabolism | Haloperidol is extensively metabolized in the liver via multiple pathways, including glucuronidation, carbonyl reduction, and CYP3A4-mediated N-dealkylation. The major active metabolite is reduced haloperidol, which can be reoxidized to haloperidol. |
| Excretion | Renal (approximately 40% as metabolites, <1% as unchanged drug); fecal (approximately 15%); remainder metabolized with unknown fate. |
| Half-life | 14–26 hours (terminal elimination half-life); may be prolonged in hepatic impairment or with repeated dosing due to accumulation. |
| Protein binding | Approximately 92%; primarily bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 10–20 L/kg (large volume indicating extensive tissue distribution, high lipophilicity, with preferential uptake in brain and adipose). |
| Bioavailability | Intramuscular: 100% (immediate-release); Oral: 60–70% (due to first-pass metabolism); Intravenous: 100%. |
| Onset of Action | Intramuscular: 30–45 minutes; Intravenous: 5–10 minutes; Oral: 1–2 hours. |
| Duration of Action | Intramuscular: 4–8 hours (acute effects); Intravenous: 3–6 hours; Oral: 12–24 hours (dose-dependent), with prolonged effects after chronic use due to depot formulations. |
| Molecular Weight | 375.86 |
2-5 mg intramuscularly or intravenously every 4-8 hours for acute agitation. Maximum 20 mg/day.
| Dosage form | SOLUTION |
| Renal impairment | No dosage adjustment required for renal impairment; monitor for adverse effects. |
| Liver impairment | Child-Pugh Class A: no adjustment; Class B: reduce dose by 50%; Class C: avoid or reduce dose by 75%. |
| Pediatric use | Children 3-12 years: 0.05-0.15 mg/kg/day intramuscularly in divided doses every 4-8 hours, not to exceed 0.5 mg/kg/day. |
| Geriatric use | Initiate at 0.5-2 mg/day intramuscularly; increase gradually. Reduce dose by 50-75% compared to younger adults; monitor for QT prolongation and EPS. |
| 1st trimester | Limited human data; butyrophenones are not major teratogens. Use only if clearly needed and potential benefit outweighs risk. |
| 2nd trimester | Monitor for maternal extrapyramidal symptoms and gestational diabetes. Use only if clearly needed. |
| 3rd trimester | Risk of neonatal extrapyramidal symptoms and withdrawal after delivery if used near term, and may cause prolonged QT interval in neonate. Use with caution. |
Clinical note
CNS depressants may enhance sedative effects Can cause extrapyramidal symptoms and QT prolongation.
| FDA category | Animal |
| Placental transfer | Haloperidol crosses the placenta; fetal plasma concentrations are approximately 50-80% of maternal levels. |
| Breastfeeding |
■ FDA Black Box Warning
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Haloperidol lactate is not approved for the treatment of dementia-related psychosis.
| Common Effects | Tourette's syndrome |
| Serious Effects |
Coma or severe CNS depressionParkinson's diseaseHypersensitivity to haloperidol or any componentSevere toxic CNS depressionPre-existing QT prolongation or risk factor (e.g., hypokalemia, hypomagnesemia, bradycardia, drugs that prolong QT interval)
| Precautions | Increased mortality in elderly patients with dementia-related psychosis, QT interval prolongation and risk of torsades de pointes, Tardive dyskinesia with prolonged use, Neuroleptic malignant syndrome (NMS), Hypotension and hypertension, Seizures, Leukopenia, neutropenia, and agranulocytosis, Drug interaction with alcohol and CNS depressants, Avoid use in patients with Parkinson's disease or Lewy body dementia |
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| Haloperidol is excreted into breast milk in low concentrations. Monitor the infant for sedation, extrapyramidal symptoms, and poor feeding. The American Academy of Pediatrics considers haloperidol to be compatible with breastfeeding. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | First trimester: Epidemiological data do not suggest a substantial increased risk of major malformations, but there is limited evidence of possible risk of limb defects (rare). Second and third trimesters: Risk of extrapyramidal symptoms and/or withdrawal symptoms in neonates after in utero exposure. Use only if benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal mental status, EPS, QT interval (ECG), blood pressure, and serum prolactin. Fetal monitoring: ultrasound for fetal growth and amniotic fluid index if used in pregnancy. Neonatal monitoring: evaluate for extrapyramidal symptoms, sedation, and withdrawal after delivery. |
| Fertility Effects | Haloperidol may increase serum prolactin levels, which can cause galactorrhea, amenorrhea, and gynecomastia, potentially impairing fertility in both sexes. The effect is reversible upon discontinuation. |
| Food/Dietary |
| Haloperidol lactate has no significant food interactions. Grapefruit and grapefruit juice do not affect its metabolism. However, patients should avoid excessive caffeine intake as it may exacerbate agitation or anxiety. Alcohol should be avoided due to additive CNS depression and potential for disulfiram-like reactions with some formulations. |
| Clinical Pearls | Haloperidol lactate is a first-generation antipsychotic with high potency and a strong D2 receptor antagonism. For acute agitation, IM administration provides onset within 30-45 minutes. ECG monitoring is essential due to dose-dependent QT prolongation, especially at cumulative doses >35 mg/day. Avoid IV use unless absolutely necessary due to risk of hypotension and cardiovascular collapse. Concomitant use with other QT-prolonging drugs requires extreme caution. Tardive dyskinesia risk increases with cumulative dose and treatment duration; regular AIMS assessments are recommended. In elderly patients with dementia-related psychosis, black box warning for increased mortality; use only when non-pharmacologic options fail. |
| Patient Advice | Take this medication exactly as prescribed; do not stop suddenly without consulting your doctor. · Avoid alcohol and recreational drugs while on this medication. · Report any involuntary muscle movements, especially of the face or tongue, to your doctor immediately. · Rise slowly from sitting or lying positions to reduce risk of dizziness and falls. · This medication may impair judgment, thinking, or motor skills; avoid driving or hazardous activities until you know how it affects you. · Stay hydrated in hot weather as this drug can impair body temperature regulation. |