Typical depot antipsychotic Pregnancy: Safety in pregnancy has not been established - avoid during pregnancy, especially the first and last trimesters, unless the expected benefit outweighs the potential risk to the foetus. Neonates exposed to antipsychotics during the third trimester are at risk of extrapyramidal and/or withdrawal symptoms (agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, feeding disorder) and should be monitored carefully. Flupentixol is excreted into breast milk - if treatment is considered essential, nursing mothers should stop breast-feeding. Hyperprolactinaemia, galactorrhoea, amenorrhoea and sexual dysfunction may affect fertility; consider dose reduction or discontinuation (SPC 4.6).

Flupentixol decanoate

Brand names: Depixol, Modecate

Flupentixol decanoate is a long-acting depot formulation of the thioxanthene antipsychotic flupentixol, given by deep intramuscular injection for maintenance treatment of schizophrenia and related psychoses.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Usual dosage lies between 50 mg every 4 weeks and 300 mg every 2 weeks; in patients not previously given a depot antipsychotic, start with a small test dose (e.g. 20 mg) to assess tolerability

Route: Deep intramuscular injection into the upper outer buttock or lateral thigh

Frequency: Every 2 to 4 weeks, adjusted to symptoms and response; allow an interval of at least one week after the initial test dose before the second injection

Max: Maximum single dose 400 mg at any one time (e.g. 800 mg every 2 weeks should not be given); some patients may require up to 400 mg weekly

Source product is Depixol 20 mg/ml solution for injection. Other patients may be adequately maintained on 20-40 mg flupentixol decanoate every 2-4 weeks. The 20 mg/ml strength is not intended for patients requiring doses greater than 60 mg (3 ml); injection volumes of 2-3 ml should be distributed between two injection sites, and more concentrated solutions (Depixol Conc Injection or Depixol Low Volume Injection) should be used if doses greater than 3 ml (60 mg) are required, with volumes for those preparations not exceeding 2 ml. Adequate control of severe psychotic symptoms may take up to 4 to 6 months at high enough dosage; once stabilised, lower maintenance doses may be considered but must be sufficient to prevent relapse. Older or frail patients: initial dosage may need to be reduced to a quarter or half the normal starting dose. Hepatic impairment: flupentixol has not been studied; it is extensively metabolised by the liver, so particular caution is needed and serum level monitoring is advised. Depixol should be initiated at low doses orally to check tolerability before switching to the depot formulation. As with all oil-based injections, aspirate before injection to ensure inadvertent intravascular entry does not occur. When transferring from oral to depot treatment, do not stop the oral medication immediately - withdraw it gradually over several days after the first injection. Plasma concentrations decrease gradually over several weeks, making gradual dose tapering unnecessary on discontinuation. Paediatric: Depixol is not recommended for use in children due to lack of clinical experience. eMC section 4.5 was not captured in this bundle (section 4.4 truncated at the source-fetch limit), so no interaction list is given.

Dose adjustments

Renal

Flupentixol has not been studied in renal impairment; increased cerebral sensitivity to antipsychotics has been noted in severe renal impairment. No numeric dose adjustment is stated (SPC 4.2, 4.4).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
Circulatory collapse
Depressed level of consciousness due to any cause (e.g. intoxication with alcohol, barbiturates or opiates)
Coma
Not recommended for excitable or agitated patients

Side effects

Somnolence, akathisia, hyperkinesia, hypokinesia (very common); tremor, dystonia, dizziness, headache (common); tardive dyskinesia, parkinsonism and convulsion (uncommon to rare)
Dry mouth (very common); salivary hypersecretion, constipation, vomiting, dyspepsia, diarrhoea (common)
Insomnia, depression, nervousness, agitation, decreased libido (common); suicidal ideation and suicidal behaviour (not known)
Increased appetite and weight increase (common); hyperglycaemia and abnormal glucose tolerance (rare)
Tachycardia and palpitations (common); QT prolongation on ECG (rare); hypotension (uncommon); venous thromboembolism (not known)
Accommodation disorder and abnormal vision (common); micturition disorder and urinary retention (common)
Neuroleptic malignant syndrome (very rare); blood dyscrasias including agranulocytosis (rare)

Clinical monograph

How it works

After injection the decanoate ester is slowly hydrolysed to release flupentixol, which antagonises dopamine D2 receptors to provide sustained antipsychotic effect.

Prescribing in practice

A test dose is required before establishing maintenance therapy because the long action means adverse effects, including extrapyramidal reactions, are not readily reversible.
As with oral flupentixol, avoid in overactive or excited patients owing to a potential alerting effect.
Antipsychotics carry risks of QT prolongation and increased stroke and mortality in elderly patients with dementia.

Monitoring

Monitor for extrapyramidal symptoms, injection-site reactions and metabolic and cardiac effects throughout depot treatment.

Counselling the patient

This is a long-acting injection given at regular intervals by a health professional.
Report muscle stiffness, restlessness, tremor or high fever.
Keep follow-up appointments so treatment can be monitored and adjusted.

Evidence & guidelines

Long-acting antipsychotic injections are an established maintenance strategy for improving adherence in schizophrenia.

Reference: Maudsley Prescribing Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Haloperidol decanoate · Typical depot antipsychotic

Pathways