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Haloperidol is a classic first-generation (typical) antipsychotic used for schizophrenia, acute agitation and psychosis. It works primarily by blocking dopamine D2 receptors, which dampens the excess dopamine signaling linked to psychotic symptoms. It is effective but carries a high burden of movement side effects, and it is not a recreational drug; taken by someone who is not psychotic it tends to feel unpleasant and flattening.
- Reduces hallucinations and delusions
- Calms acute agitation
- Long track record and injectable forms
- Stiffness, tremor and restlessness
- Tardive dyskinesia with long-term use
- QT prolongation and arrhythmia risk
- Rare neuroleptic malignant syndrome
Mechanism
Haloperidol is a potent at receptors. Blocking D2 signaling in the mesolimbic pathway reduces the hallucinations and delusions of psychosis, but the same blockade in the nigrostriatal pathway disrupts motor control, producing the extrapyramidal (movement) side effects the drug is known for. It has relatively little antihistamine or anticholinergic activity compared with some antipsychotics, so its side-effect profile is dominated by dopamine blockade.
receptor fingerprint
receptorAntagonist
Safetyrisks and cautions, not medical advice
Because it strongly blocks dopamine, haloperidol commonly causes extrapyramidal effects: stiffness, tremor, restlessness (akathisia) and, with long-term use, potentially irreversible tardive dyskinesia. It can prolong the heart's QT interval, raising arrhythmia risk, and rarely triggers neuroleptic malignant syndrome, a life-threatening reaction with high fever and rigidity. It adds to sedation and QT risk when combined with other depressants or QT-prolonging drugs. Not medical advice.
Interactionsdocumented pairs only, not exhaustive
The interaction that matters most with haloperidol is cardiac. It blocks the hERG potassium channel and prolongs the QT interval, and that risk compounds with other QT prolonging drugs: class IA and class III antiarrhythmics, methadone, ondansetron, macrolides, fluoroquinolones and most other antipsychotics. Diuretic induced hypokalaemia or hypomagnesaemia raises the risk further, and the intravenous route carries the highest torsades risk.
Haloperidol is metabolised by CYP3A4 and CYP2D6. Strong CYP3A4 inducers such as carbamazepine, rifampin and phenytoin can halve plasma concentrations and precipitate relapse, while CYP2D6 inhibitors including paroxetine, fluoxetine and quinidine push concentrations up along with extrapyramidal symptoms.
Lithium combined with haloperidol has produced an encephalopathic syndrome of confusion, rigidity and fever resembling neuroleptic malignant syndrome. Haloperidol also antagonises levodopa and dopamine agonists, worsening parkinsonism, and adds to the sedation of alcohol and other depressants.
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Subjective profileweighing the evidence above
Effective and still worth having for acute psychosis and agitation, but the burden is heavy: stiffness, restlessness, potentially permanent tardive dyskinesia, QT prolongation, and rare neuroleptic malignant syndrome. A supervised prescription for a specific problem, and flattening and unpleasant for anyone else.
Resources
This entry is here for reference.
Research
- 1.Antipsychotics, dopamine D₂ receptor occupancy and clinical improvement in schizophrenia: a meta-analysis.
- 2.Antipsychotic dose, dopamine D2 receptor occupancy and extrapyramidal side-effects: a systematic review and dose-response meta-analysis
2 listed here; entry last updated August 2026
Reviews
My notesprivate to this device
FAQ
What is haloperidol used for?
Mainly schizophrenia, other psychotic disorders and acute agitation; it is one of the oldest and most established antipsychotics.
Why does it cause movement problems?
Its strong dopamine D2 blockade also affects the brain's motor circuits, which can cause stiffness, tremor, restlessness and, over time, tardive dyskinesia.
Is it something people take recreationally?
No. It is not euphoric; in someone who is not psychotic it tends to feel flat, restless and unpleasant, and it carries real movement and heart risks.
Adverse effects
- Stiffness, tremor and restlessness
- Tardive dyskinesia with long-term use
- QT prolongation and arrhythmia risk
- Rare neuroleptic malignant syndrome