Antipsychotics · Psychiatry
Haloperidol
Haldol®(brand names vary by market)
Pure, potent D2 blockade: metabolically clean and neurologically expensive.
Also: oral liquid, injection
Mechanism
High-potency typical antipsychotic with strong D2 antagonism and little affinity for histamine or muscarinic receptors.
Indications
- Acute psychosis and severe agitation
- Schizophrenia
- Delirium with severe distress or risk
- Nausea in palliative care
- Tourette syndrome
Formulations
Dosing concepts
Delirium
Used at low doses and only when distress or danger cannot be managed non-pharmacologically. It treats the behaviour, never the delirium, and the cause still has to be found.
Palliative nausea
Low doses are an effective antiemetic for chemical causes such as opioids, hypercalcemia and uraemia.
Concepts, not prescribing instructions. Practice numbers live in current references and local protocols.
Pharmacokinetics
- Bioavailability
- ~60% oral
- Half-life
- 14 to 26 h
- Elimination
- hepatic: CYP3A4 and CYP2D6
- Protein binding
- ~90%
Adverse effects
- Extrapyramidal symptomscommon & seriousThe highest of the commonly used agents: acute dystonia, parkinsonism, akathisia, and tardive dyskinesia with time.
- QT prolongation and torsadesseriousParticularly with intravenous administration and with electrolyte disturbance.
- Neuroleptic malignant syndromeserious
- Hyperprolactinemiacommon
- Increased mortality in older adults with dementiaserious
Contraindications & precautions
Contraindications
- Parkinson disease and Lewy body dementia
- Known QT prolongation
- Severe CNS depression
Precautions
- Older adults
- Electrolyte disturbance
- Concurrent QT-prolonging drugs
- Alcohol withdrawal, where a benzodiazepine is the correct drug
Interactions
No curated interaction entries yet for this agent.
Monitoring
ECG, particularly with intravenous use or repeated dosing
QT prolongation and torsades
Potassium and magnesium
They set the torsades risk
Movement examination
Acute dystonia can appear within hours of a first dose
Counselling points
- Tell staff immediately about muscle stiffness, an involuntarily turned neck, or eyes rolling upward: this is treatable within minutes.
- Report restlessness or an inability to keep still.
- It may be given briefly and then stopped; it is not usually a long-term medicine in delirium.
Clinical pearls
- In Lewy body dementia and Parkinson disease, D2 blockade can cause a severe and sometimes irreversible deterioration. This is one of the sharpest contraindications in the whole formulary.
- Haloperidol in delirium is a rescue for distress, not a treatment; the delirium is caused by something else and that something is the actual job.
- Acute dystonia responds to an anticholinergic within minutes, and knowing that turns a frightening event into a manageable one.
References & review
- Haloperidol product monograph (consult the current version for your market) (monograph)
- Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed. (reference-work)
Last reviewed 2026-08-16 · jurisdiction: global · drug information changes; verify against current references before practice use.