fluphenazine

General information

• Class: Antipsychotic
• Common US brands: Prolixin
• Typical dose range: Oral: typical start is 2.5–5 mg/day divided; titrate to 5–20 mg/day; rarely exceed 40 mg/day.
• Long-acting injectable formulation available.
• Therapeutic drug monitoring not routinely recommended.
• Last reviewed: 2025-12-29

Dosing & forms

• Forms/strengths: Oral tablets 1–10 mg, oral elixir 2.5 mg/5 mL, lactate injection 2.5 mg/mL, decanoate depot 25 mg/mL (IM every 2–4 weeks).
• Typical range: Oral: typical start is 2.5–5 mg/day divided; titrate to 5–20 mg/day; rarely exceed 40 mg/day.

Mechanism (brief)

High-potency phenothiazine antipsychotic with strong dopamine D2 antagonism; long-acting decanoate available for depot dosing.

Metabolism & Half‑life

• Metabolism: CYP2D6
• Half‑life: Single-dose mean 15 h

Therapeutic Drug Monitoring (TDM)

Recommended: No

Long‑acting injectable (LAI)

Monitoring highlights

• Baseline and ongoing EPS monitoring (SAS/Barnes scales when available) and AIMS screening (often every 3–6 months) for tardive dyskinesia.
• Weight/BMI and metabolic labs periodically even with lower metabolic liability, because overall cardiometabolic risk remains important in schizophrenia care.
• Orthostatic vitals and falls risk during titration and after depot dose or interval changes; adjunctive medications are reviewed accordingly.
• Prolactin-related symptoms (sexual dysfunction, amenorrhea, galactorrhea) and overall functioning—consider switching if persistent.
• ECG monitoring in cardiac disease, electrolyte abnormalities, high-dose therapy, or when combining with QT-active medications.
• Depot adherence and injection-site assessments at each visit; review missed-dose plans and clinic access reliability.

Sources

• Fluphenazine decanoate prescribing information — DailyMed (2024)
• Triple advantages of injectable long acting second generation antipsychotics: relapse prevention, neuroprotection, and lower mortality — Schizophrenia Research (2018)
• The American Psychiatric Association Practice Guideline for the Treatment of Patients With Schizophrenia — American Psychiatric Association (2020)
• Comparative efficacy and tolerability of 15 antipsychotic drugs in schizophrenia: a multiple-treatments meta-analysis — The Lancet (2013)
• CANMAT and ISBD Guidelines for the Management of Patients With Bipolar Disorder: 2021 Update — Bipolar Disorders (2021)