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fluphenazine decanoate

Long-acting injectable antipsychoticLAI available

Brands: PROLIXIN DECANOATE

Last reviewed 2025-12-30

Reviewed by PsychMed Editorial Team.

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Quick answers

  • What is fluphenazine decanoate?

    Fluphenazine decanoate (often known by the Prolixin Decanoate brand) is a long-acting injectable formulation used for schizophrenia maintenance. It can reduce relapse risk driven by missed daily doses by making treatment a scheduled injection visit.

  • What is PROLIXIN DECANOATE?

    PROLIXIN DECANOATE is a brand name for fluphenazine decanoate.

  • What is PROLIXIN DECANOATE (fluphenazine decanoate) used for?

    Label indications include: Schizophrenia (maintenance treatment).

  • What drug class is PROLIXIN DECANOATE (fluphenazine decanoate)?

    Long-acting injectable antipsychotic.

  • What is the mechanism of action of PROLIXIN DECANOATE (fluphenazine decanoate)?

    Long-acting injectable formulation of fluphenazine (high-potency phenothiazine D2 antagonist) used for schizophrenia maintenance when depot dosing supports adherence.

  • What strengths does PROLIXIN DECANOATE (fluphenazine decanoate) come in?

    Long-acting depot injection: deep intramuscular injection, typically administered every 2–4 weeks (interval depends on dose and response).

  • Is PROLIXIN DECANOATE (fluphenazine decanoate) a controlled substance?

    No — it is not scheduled as a controlled substance under U.S. federal law.

Snapshot

  • Class: Long-acting injectable antipsychotic
  • Common US brands: PROLIXIN DECANOATE
  • Long-acting injectable formulation available.
  • Therapeutic drug monitoring not routinely recommended.
  • Last reviewed: 2025-12-30

Label indications

Schizophrenia (maintenance treatment).

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Clinical Highlights

Fluphenazine decanoate (often known by the Prolixin Decanoate brand) is a long-acting injectable formulation used for schizophrenia maintenance. It can reduce relapse risk driven by missed daily doses by making treatment a scheduled injection visit. This page focuses on the depot product. For oral fluphenazine and general FGA risks, see the fluphenazine overview. For depot interval comparisons across antipsychotics, see the LAI Navigator.

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  • Fluphenazine is a high-potency first-generation antipsychotic (FGA). It tends to have relatively low metabolic burden, but higher risk of EPS and tardive dyskinesia compared with many SGAs. Prolactin elevation and QTc considerations are also practical monitoring topics.
  • Depot dosing is typically every 2–4 weeks. Because drug release is prolonged, clinical changes after dose adjustments can lag behind the clinic encounter, which influences how quickly teams can respond to underdosing or adverse effects.
  • The compare view can help compare depot options; the evidence feed tracks curated reading for this formulation.
  • Schizophrenia (adults): long-acting maintenance formulation.

Dosing & Formulations

Deep intramuscular depot injection, typically administered every 2–4 weeks depending on dose and response. Confirm injection technique and interval in product labeling and local protocols. Conversion from oral therapy is individualized. Many clinicians establish oral tolerability first, then transition to depot dosing with clear documentation of target interval, dose, and missed-dose plan.

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  • Dose adjustments can be slower than with oral antipsychotics because depot release persists between visits; teams often assess across multiple injection cycles before declaring a regimen ineffective.

Monitoring & Risks

Boxed warning: increased mortality in elderly patients with dementia-related psychosis (antipsychotic class warning). EPS and tardive dyskinesia are key risks; routine movement-disorder monitoring (e.g., AIMS) is commonly used, particularly in high-risk patients and after dose increases.

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  • Prolactin-related adverse effects can occur (sexual dysfunction, menstrual changes, galactorrhea); monitoring is usually symptom-driven.
  • QTc: consider ECG monitoring when clinically indicated (baseline cardiac disease, electrolyte disturbances, or QT-prolonging co-medications).
  • Sedation and orthostasis can occur, especially with polypharmacy, but are often less prominent than with some sedating SGAs.

Drug Interactions

Fluphenazine is metabolized in part via CYP2D6; strong inhibitors can increase exposure and adverse effects. Additive QTc prolongation risk occurs with other QT-prolonging medications; risk is individualized to baseline QTc and clinical factors.

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  • Additive CNS depression can occur with alcohol, benzodiazepines, or sedative hypnotics; monitor falls risk and daytime functioning.
  • Combining dopamine-blocking agents increases EPS burden; consider movement-disorder monitoring when combinations are unavoidable.

Practice Notes

Depot success is often about workflow: reminders, reliable scheduling, and clear documentation of last injection date and site. Because washout is slow, adverse effects can persist for weeks after dose changes. Early recognition of akathisia/parkinsonism and prompt management are often more effective than waiting for rapid washout.

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  • Given higher risk of acute dystonia/akathisia with high-potency FGAs, some clinics document a simple “what to do if severe EPS shows up” plan at initiation (including who to call and when to seek urgent evaluation).
  • Use the print handout for clinic workflows and the schizophrenia hub for relapse-prevention pathways.

Long-acting injectable (LAI) options

  • Fluphenazine decanoate
    Interval
    q2–4wk
    Oral overlap
    Consider during conversion
    Injection site
    Gluteal
    Notes
    • Approximate conversion often cited ~1.2× daily oral dose every 2–3 weeks; verify in label

References

  1. Fluphenazine decanoate prescribing information (DailyMed). — DailyMed (2024)
  2. The American Psychiatric Association Practice Guideline for the Treatment of Patients With Schizophrenia — American Psychiatric Association (2020)
  3. Comparative Efficacy AND Tolerability OF 15 Antipsychotic Drugs IN Schizophrenia: A Multiple Treatments Meta Analysis — The Lancet (2013)Meta-analysisschizophreniaefficacy
  4. AGNP Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology — Pharmacopsychiatry (2018)
  5. Triple advantages of injectable long acting second generation antipsychotics: relapse prevention, neuroprotection, and lower mortality — Schizophrenia Research (2018)
Fluphenazine decanoate (PROLIXIN DECANOATE) — Summary — PsychMed