Flupentixol is a typical antipsychotic belonging to the thioxanthene class, developed in the 1960s and introduced into clinical use in Europe in the late 1960s and 1970s. It is primarily used in the management of schizophrenia and other psychotic disorders, and at lower doses it has also been used in some countries as an adjunct in depressive and anxiety-related conditions. Its pharmacological action is mainly due to dopamine D2 receptor antagonism in the central nervous system, which helps reduce hallucinations, delusions, and disorganized thinking. Flupentixol is available in both oral and long-acting depot injectable formulations, such as flupentixol decanoate, which allows sustained symptom control and improved treatment adherence in chronic psychiatric illness. It is marketed under brand names such as Fluanxol in several regions. While effective, its clinical use is also associated with notable adverse effects, particularly extrapyramidal symptoms, which reflect its dopamine-blocking activity.
BRAND NAMES
Fluanxol (most widely known brand; tablets and depot injection)
Depixol (common brand for long-acting injectable flupentixol decanoate)
Flupentixol decanoate (often sold under various generic/depot injection brand names in different regions)
Fluanxol Depot (injectable long-acting formulation in some markets)
MECHANISM OF ACTION
Flupentixol is a typical antipsychotic belonging to the thioxanthene class that works primarily by blocking dopamine D2 receptors in the central nervous system. By reducing dopamine activity in the mesolimbic pathway, it helps control positive symptoms of psychosis such as hallucinations, delusions, and disorganized thinking. At lower doses, it may exert a mild antidepressant and anxiolytic effect, likely due to modulation of dopaminergic transmission in additional brain pathways
PHARMACOKINETICS
Absorption:
Flupentixol is well absorbed following oral administration, with peak plasma concentrations typically reached within a few hours. Long-acting depot formulations, such as flupentixol decanoate, are slowly released from intramuscular injection sites, providing sustained drug levels over weeks.
Distribution:
Flupentixol is widely distributed in body tissues and is highly protein bound in plasma. It crosses the blood–brain barrier to exert its antipsychotic effects in the central nervous system.
Metabolism:
It is extensively metabolized in the liver, mainly through oxidative pathways, producing inactive metabolites.
Elimination:
Flupentixol and its metabolites are excreted primarily via feces and to a lesser extent in urine. Depot formulations have a prolonged elimination phase due to slow release from muscle tissue.
PHARMACODYNAMICS
Flupentixol acts mainly as a dopamine D2 receptor antagonist, reducing dopaminergic neurotransmission in the mesolimbic system, which is responsible for psychotic symptoms. It also has moderate affinity for other receptors, including serotonin and adrenergic receptors, contributing to its overall clinical profile. At higher doses, dopamine blockade leads to antipsychotic effects, while at lower doses, partial modulation of neurotransmission may contribute to antidepressant activity.
ADMINISTRATION
Flupentixol is administered orally in tablet form or as a long-acting intramuscular depot injection (flupentixol decanoate). Oral dosing is typically given once or multiple times daily depending on severity, while depot injections are given every 2–4 weeks for maintenance therapy in chronic psychotic disorders.
DOSAGE AND STRENGTH
Oral flupentixol is available in low and moderate doses, commonly ranging from 0.5 mg to 10 mg tablets depending on clinical need. For depot injections (flupentixol decanoate), doses are typically expressed in milligrams and administered every 2–4 weeks, with usual maintenance doses varying widely.
DRUG INTERACTIONS
Flupentixol may interact with other central nervous system depressants such as alcohol, sedatives, and opioids, leading to enhanced sedation. It can also interact with antihypertensive drugs, increasing the risk of hypotension. Concomitant use with other dopamine antagonists or drugs that prolong the QT interval may increase the risk of cardiac and neurological adverse effects.
FOOD INTERACTIONS
There are no significant food interactions with flupentixol. However, alcohol consumption should be avoided as it can enhance sedation and impair central nervous system function.
CONTRAINDICATIONS
Flupentixol is contraindicated in patients with hypersensitivity to the drug, severe central nervous system depression, comatose states, and phaeochromocytoma. It should also be used with caution in patients with Parkinson’s disease due to its dopamine-blocking effects.
SIDE EFFECTS
Drowsiness or sedation
Dry mouth
Dizziness
Extrapyramidal symptoms (tremors, rigidity, akathisia)
Weight gain
Blurred vision
Orthostatic hypotension
Restlessness or agitation
Sexual dysfunction.
OVERDOSAGE
Overdosage with flupentixol is uncommon but can occur, especially with high oral intake or inappropriate dosing of depot formulations. Toxic effects are mainly due to excessive dopamine receptor blockade in the central nervous system and peripheral nervous system.
TOXICITY
Flupentixol toxicity is mainly related to excessive dopamine blockade and may present as severe extrapyramidal symptoms, rigidity, confusion, sedation, hypotension, or in rare cases neuroleptic malignant syndrome (a life-threatening condition characterized by fever, muscle rigidity, and autonomic instability). Management involves discontinuation of the drug, supportive care, and symptomatic treatment depending on severity.
