Haloperidol

What haloperidol is and how it works

Haloperidol is a prescription conventional antipsychotic. Product labels and approved uses differ by country and formulation. It is not suitable for self-treatment, and oral, short-acting injection, and long-acting decanoate products must be kept distinct. (1) (2) (3)

Take oral haloperidol exactly as prescribed and do not stop it suddenly. Injections are administered by healthcare professionals; long-acting decanoate treatment requires product-specific clinical planning and follow-up. Tell the prescriber about all medicines, heart problems, movement symptoms, and Parkinson disease before treatment.

Mechanism of action: how haloperidol works

Haloperidol is a conventional antipsychotic. Its clinical effects and adverse effects require formulation-specific prescribing and monitoring; the public page does not substitute for specialist assessment. (2) (3) (8)

What is Haloperidol used for?

Before taking haloperidol

Do not take / not appropriate for

• Do not use haloperidol if you have had a hypersensitivity reaction to it or its ingredients. (all countries) (2)
• Do not use it in coma or severe central-nervous-system depression unless a specialist using the applicable product information directs otherwise. (United States tablet label) (2)
• The US tablet label lists Parkinson disease as a contraindication. Ask the prescribing clinician before use if you have Parkinson disease or another movement disorder. (United States tablet label) (2) (1)

Tell your clinician about

• Any heart disease, fainting, slow heartbeat, known long-QT syndrome, or a history of abnormal heart rhythm.
• Low potassium or magnesium, vomiting/diarrhoea, or medicines that can affect heart rhythm.
• Parkinson disease, previous involuntary movements, stiffness, tremor, or a past reaction to an antipsychotic.
• All prescription medicines, over-the-counter products, alcohol use, and recreational drugs; interactions may be clinically important.
• Pregnancy, plans for pregnancy, breastfeeding, or a child or older adult receiving treatment; individual specialist advice is required.
• Any history of dementia-related psychosis in an older adult. Haloperidol is not approved for this use in the United States and carries an increased mortality warning.

Haloperidol dosage and how to take it

• Use haloperidol exactly as prescribed; do not change the dose or schedule yourself.
• For oral medicine, follow the label and use the measuring device supplied or recommended for liquid products.
• Do not stop oral haloperidol suddenly; the clinician should advise how to change or stop treatment.
• Short-acting injection and long-acting decanoate injection are given by trained healthcare professionals, not self-administered.
• Keep follow-up appointments, especially for injection or depot treatment.
• Avoid alcohol and ask about driving or machinery because haloperidol can impair alertness.

Before procedures or hospital care

Tell every clinician, dentist, pharmacist, and anaesthetist that you take haloperidol. The exact product and timing of the last oral or injection dose matter for interaction and heart-rhythm assessment. (1) (4)

Missed dose

Do not take an extra dose to make up for a missed oral dose. Ask the prescriber or pharmacist for instructions specific to your product and schedule. If an injection appointment is missed, contact the clinic promptly rather than trying to rearrange the dose yourself.

Overdose

If too much haloperidol has been taken or injected, or someone is very drowsy, fainting, has a seizure, severe stiffness, breathing difficulty, or an irregular heartbeat, seek emergency medical help or contact a poison service immediately. Take the medicine package or injection details with you. (1) (2) (5)

Haloperidol side effects

Haloperidol can cause effects on alertness and movement. New or worsening movement symptoms, fever with rigidity, fainting, or palpitations need prompt clinical assessment.

Serious warnings

Interactions

Pregnancy, breastfeeding, kidney/liver function, age

Monitoring

Before starting

• Confirm the exact formulation: oral, short-acting injection, or long-acting decanoate injection.
• Review heart history, fainting, rhythm risk, electrolytes, and all current medicines.
• Record baseline movement symptoms and any history of tardive dyskinesia or other antipsychotic reactions.
• Confirm the plan for follow-up and, for injections, where and when treatment will be administered.

During treatment

• Keep scheduled clinical and injection appointments.
• Report new involuntary movements, stiffness, tremor, restlessness, sedation, dizziness, palpitations, or fainting.
• Seek urgent care for fever with severe stiffness or confusion, or for collapse, seizure, or severe breathing difficulty.
• Do not stop or alter the dose without the prescribing clinician's plan.

Storage

Store oral products in their original container and follow the exact product label. Keep all medicines out of reach of children. Injection products are generally handled and stored by healthcare services.

United States: Follow the storage instructions on the exact tablet or liquid label. (2) (1)

New Zealand: Follow the data sheet and instructions for the exact oral or injection product. (7) (8)

Frequently asked questions

References

1. Haloperidol: MedlinePlus Drug InformationMedlinePlus, U.S. National Library of Medicine · United States · dated 2026-03-15 · accessed 2026-07-21 · source 1
2. HALOPERIDOL (haloperidol) tablet — professional labelDailyMed, U.S. National Library of Medicine · United States · dated current label accessed 2026-07-21 · accessed 2026-07-21 · source 2
3. Haloperidol Injection: MedlinePlus Drug InformationMedlinePlus, U.S. National Library of Medicine · United States · dated 2026-03-15 · accessed 2026-07-21 · source 3
4. HALDOL 2 mg/ml oral solution — Summary of Product Characteristicselectronic Medicines Compendium (UK licensed medicine information) · United Kingdom · dated 2023-11-06 · accessed 2026-07-21 · source 4
5. Haloperidol 1 mg/ml Oral Solution — Patient Information Leafletelectronic Medicines Compendium (UK licensed medicine information) · United Kingdom · dated 2022-07 · accessed 2026-07-21 · source 5
6. HALOPERIDOL MEDICIANZ haloperidol 5 mg/1 mL solution for injection ampoule (ARTG 449665)Therapeutic Goods Administration · Australia · dated 2025-07-28 · accessed 2026-07-21 · source 6
7. SERENACE haloperidol tablets, liquid and injection — New Zealand Data SheetMedsafe New Zealand · New Zealand · dated current data sheet accessed 2026-07-21 · accessed 2026-07-21 · source 7
8. HALDOL haloperidol decanoate injection — New Zealand Data SheetMedsafe New Zealand · New Zealand · dated current data sheet accessed 2026-07-21 · accessed 2026-07-21 · source 8

Brand names by country

Single-ingredient haloperidol names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries