Flupenthixol is a thioxanthene antipsychotic indicated for the treatment of schizophrenia and other psychotic disorders. Important Note: This medication is not available in the United States but is used in many other countries including the UK, Canada, and Australia. It is available in both oral and long-acting injectable formulations.
Clinical Overview
Primary Clinical Applications
Flupenthixol is indicated for schizophrenia, acute and chronic psychoses, and maintenance treatment of psychotic disorders. It is also sometimes used for severe anxiety and agitation. The long-acting injection (flupenthixol decanoate) provides 2-4 week dosing intervals for maintenance therapy.
Mechanism and Clinical Characteristics
As a dopamine D1 and D2 receptor antagonist, flupenthixol provides antipsychotic efficacy similar to other typical antipsychotics. It has moderate sedating properties and carries the typical side effect profile of first-generation antipsychotics, including extrapyramidal symptoms and tardive dyskinesia risk.
Formulation Advantages
Available as oral tablets and long-acting injection. The depot formulation improves medication adherence in patients with chronic psychotic disorders and provides consistent therapeutic levels over extended periods.
Key Clinical Points
Not available in the United States
Used in the UK, Canada, Australia, and elsewhere but not FDA-approved. Relevant when reviewing medication histories for patients who have transferred care internationally.
Depot formulation for adherence
Flupenthixol decanoate gives two to four week dosing intervals at 50 to 300 mg maintenance, which is the principal reason it remains in use for chronic psychotic illness.
Contraindicated in Parkinson's disease
D1 and D2 antagonism will worsen parkinsonian symptoms. Also contraindicated in comatose states, severe CNS depression, and phaeochromocytoma.
QT prolongation requires dose restraint
Avoid in known QT prolongation, congenital long QT syndrome, significant bradycardia, recent myocardial infarction, uncompensated heart failure, electrolyte disturbance, or alongside other QT-prolonging drugs. Use the lowest effective dose.
First-generation side-effect profile
Extrapyramidal symptoms are common and dose-related, with tardive dyskinesia risk accumulating over time and hyperprolactinaemia expected. Increased mortality applies in elderly patients with dementia-related psychosis.
Prescribing Information
Dosing & Administration
Schizophrenia – Oral:
- Initial: 3-9 mg daily in divided doses
- Maintenance: 3-18 mg daily
- Maximum: 18 mg daily
Elderly – Oral:
- Initial: 1.5-3 mg daily
- Maintenance: 3-6 mg daily
Long-Acting Injection (Decanoate):
- Initial: 20-40 mg every 2-4 weeks
- Maintenance: 50-300 mg every 2-4 weeks
- Maximum: 400 mg weekly in severe cases
Indications
- Schizophrenia
- Acute and chronic psychoses
- Maintenance treatment of psychotic disorders
- Severe anxiety and agitation (short-term)
Contraindications
- Comatose states
- Severe CNS depression
- Parkinson’s disease
- Known hypersensitivity to flupenthixol
- Pheochromocytoma
Warnings & Precautions
- Tardive dyskinesia: Risk increases with duration of treatment
- Neuroleptic malignant syndrome: Rare but potentially fatal
- Extrapyramidal symptoms: Common, dose-related
- QT prolongation/TdP risk: Avoid in patients with known QT prolongation, congenital long QT syndrome, significant bradycardia, recent MI, uncompensated heart failure, electrolyte abnormalities, or when used with other QT-prolonging drugs; use the lowest effective dose
- Elderly patients: Increased mortality risk in dementia-related psychosis
- Seizure threshold: May be lowered
Drug Interactions
- CNS depressants: Enhanced sedation
- Anticholinergic drugs: Additive anticholinergic effects
- QT-prolonging drugs: Increased arrhythmia risk
- Lithium: Increased risk of extrapyramidal symptoms
- Dopamine agonists: Antagonistic effects
Adverse Reactions
Common:
- Extrapyramidal symptoms, sedation, weight gain
Serious:
- Tardive dyskinesia, neuroleptic malignant syndrome
Metabolic:
- Hyperprolactinemia, glucose abnormalities
Special Populations
- Availability: Not available in United States
- Pregnancy: Use only if benefits outweigh risks
- Elderly: Lower doses, increased sensitivity to adverse effects
- Hepatic impairment: Use with caution, monitor closely
Medical Disclaimer: This information is for educational purposes only and is not intended as medical advice. Always consult with qualified healthcare professionals before making any treatment decisions. Individual patient circumstances may vary significantly.
