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Typical depot antipsychotic Pregnancy: Moderate data (>400 outcomes) indicate no malformative or foeto/neonatal toxicity; as a precautionary measure, preferable to avoid use during pregnancy. Third-trimester exposure risks extrapyramidal/withdrawal symptoms in the newborn — monitor. Excreted in human milk.

Haloperidol decanoate

Brand names: Haldol decanoate

Used in: Delirium & Cognitive Impairment

Haloperidol decanoate is a long-acting depot formulation of the first-generation (typical) antipsychotic haloperidol, given by deep intramuscular injection to maintain treatment of schizophrenia and related psychotic disorders.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 10 to 15 times the previous daily dose of oral haloperidol on transition (25 to 150 mg for most patients)
Route: Deep intramuscular injection (gluteal region); must NOT be administered intravenously
Frequency: Usually 4 weeks between injections
Max: A maximum dose of 300 mg every 4 weeks must not be exceeded
Long-acting depot for maintenance antipsychotic therapy; initial dose is based on a multiple of the daily oral haloperidol dose. Continuation: adjust by up to 50 mg every 4 weeks based on response until optimal effect; most effective dose expected 50-200 mg every 4 weeks. Combined total haloperidol from both formulations must not exceed the maximum oral dose of 20 mg/day. Elderly: transition 12.5 to 25 mg; most effective range 25-75 mg every 4 weeks; combined total from both formulations must not exceed 5 mg/day oral (or the previously administered oral dose in long-term oral-treated patients). Renal impairment: no dose adjustment recommended but caution; severe impairment may need lower initial dose. Hepatic impairment: halve the initial dose. Volumes greater than 3 ml are not recommended. Paediatric: safety and efficacy in children/adolescents below 18 years have not been established; no data available.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients
  • Comatose state; central nervous system (CNS) depression
  • Parkinson's disease; Dementia with Lewy bodies; Progressive supranuclear palsy
  • Known QTc interval prolongation or congenital long QT syndrome
  • Recent acute myocardial infarction; uncompensated heart failure; history of ventricular arrhythmia or torsades de pointes
  • Uncorrected hypokalaemia; concomitant treatment with medicinal products that prolong the QT interval

Side effects

  • Extrapyramidal disorder (very common, 14%)
  • Tremor (8%); parkinsonism (7%); muscle rigidity (6%); somnolence (5%)
  • Insomnia, psychotic disorder, agitation, akathisia, dystonia (common)
  • QTc prolongation and/or ventricular arrhythmias, torsade de pointes, sudden death; tardive dyskinesia; neuroleptic malignant syndrome
  • Acute hepatic failure, hepatitis, cholestasis, jaundice (hepatobiliary)

Interactions

  • Medicinal products that prolong the QT interval (contraindicated — see 4.3)
  • Poor metabolisers of CYP2D6 may have high plasma concentrations (caution)

Clinical monograph

How it works

It is an esterified prodrug that is slowly hydrolysed to release haloperidol, a potent antagonist at central dopamine D2 receptors in mesolimbic and other pathways.

Prescribing in practice

  • Carries a high risk of extrapyramidal side effects and QT-interval prolongation, and may cause neuroleptic malignant syndrome; tardive dyskinesia can occur with long-term use.
  • Patients should be stabilised and tolerate oral haloperidol before conversion to the depot, which is given at regular intervals by deep intramuscular injection only.
  • Use with caution in the elderly, particularly those with dementia, owing to increased risk of stroke and death, and in cardiac disease.

Monitoring

Monitor for extrapyramidal symptoms, signs of tardive dyskinesia and neuroleptic malignant syndrome, and obtain ECG and serum potassium given the risk of QT prolongation.

Counselling the patient

  • Explain that the injection is long-acting and effects persist for weeks after each dose.
  • Report any abnormal movements, muscle stiffness, high fever or fainting promptly.
  • Avoid abrupt discontinuation and attend regular review appointments.

Evidence & guidelines

Haloperidol is a long-established antipsychotic whose efficacy and adverse-effect profile, including the MHRA warning on antipsychotics and stroke risk in dementia, are well documented.

Reference: Maudsley Prescribing Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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