Flupenthixol is a high-potency, first-generation (typical) thioxanthene antipsychotic. It acts as a potent dopamine D1 and D2 receptor antagonist, with additional serotonin 5-HT2A antagonism. The 0.5mg strength is primarily indicated for the maintenance treatment of chronic schizophrenia and other psychoses, and for depressive symptoms associated with schizophrenia and depression with anxiety. It is known for its long-acting properties and activating profile, making it suitable for withdrawn, apathetic, or anergic patients.
Adult: Schizophrenia/Psychosis: Initial dose: 1-3 mg daily in divided doses. Maintenance: 3-6 mg daily in divided doses or as a single morning dose. The 0.5mg tablet allows for fine titration. Max daily dose rarely exceeds 12-18 mg. For depressive symptoms: 0.5-1 mg once daily in the morning.
Note: Administer orally with or without food. To minimize insomnia, take the total daily dose in the morning. The tablet can be broken for dose titration. Avoid abrupt discontinuation.
Flupenthixol exerts its antipsychotic effect primarily by blocking postsynaptic dopamine D1 and D2 receptors in the mesolimbic and mesocortical pathways of the brain. Its blockade of D2 receptors in the nigrostriatal pathway is responsible for extrapyramidal side effects. Additional blockade of serotonin 5-HT2A receptors may contribute to a lower incidence of EPS compared to pure D2 antagonists and provide some mood-elevating effects. Its alpha-1 adrenergic blockade is minimal, leading to less sedation and hypotension.
Pregnancy: Category C: Animal studies show adverse effects. Use only if potential benefit justifies potential fetal risk. Risk of EPS or withdrawal symptoms in the neonate if used in the third trimester. Consult a psychiatrist and obstetrician.
Driving: May impair alertness, reaction time, and motor coordination, especially during initial treatment or dose changes. Advise patients not to drive or operate machinery until their individual response is known.
| Levodopa, Dopamine Agonists (e.g., Pramipexole) | Mutual antagonism of effects; flupenthixol reduces efficacy of dopaminergic drugs. | Major |
| Other CNS Depressants (Alcohol, Benzodiazepines, Opioids) | Additive CNS and respiratory depression, increased sedation. | Major |
| Anticholinergic drugs (e.g., Trihexyphenidyl, Benztropine) | May reduce EPS but can worsen constipation, blurred vision, and cognitive effects. | Moderate |
| Drugs prolonging QTc (e.g., Erythromycin, Amiodarone, TCAs, Citalopram) | Additive risk of QTc prolongation, torsades de pointes. | Major |
| Enzyme Inducers (e.g., Carbamazepine, Phenytoin, Rifampicin) | May decrease flupenthixol plasma levels, reducing efficacy. | Moderate |
| Enzyme Inhibitors (e.g., Fluoxetine, Paroxetine, Ketoconazole) | May increase flupenthixol plasma levels, increasing toxicity risk. | Moderate |
| Antihypertensives | Potentiation of hypotensive effects. | Moderate |
Same composition (Flupenthixol (0.5mg)), different brands: