Drug information of Fluphenazine


Drug group:

A phenothiazine used in the treatment of psychoses. Its properties and uses are generally similar to those of chlorpromazine.

Mechanism of effect

Phenothiazine; antagonizes dopaminergic D1 and D2 receptors; depresses release of hypothalamic and hypophyseal hormones


Fluphenazine is a trifluoro-methyl phenothiazine derivative intended for the management of schizophrenia and other psychotic disorders. Fluphenazine has not been shown effective in the management of behaviorial complications in patients with mental retardation.



Bioavailability: Rapidly absorbed

Onset: Hydrochloride salt, 1 hr; decanoate, 24-72 hr

Duration: Hydrochloride salt, 6-8 hr; decanoate, 4 weeks

Peak plasma time: Hydrochloride salt, 2 hr; decanoate, 8-10 hr

Peak effect: Decanoate, 48-96 hr


Half-life: Hydrochloride salt, 14-16 hr; decanoate, 14 days

Excretion: Urine, feces


Psychotic Disorders

Fluphenazine hydrochloride

2.5-10 mg/day PO divided q6-8hr initially; maintenance: 1-5 mg PO/IM divided q6-8hr; not to exceed 40 mg/day

Fluphenazine decanoate

12.5-25 mg (25 mg/mL) IM/SC every 2-4 weeks

Dosing considerations

Conversion from hydrochloride salt to decanoate: 10 mg/day PO HCl salt = ~12.5 mg IM/SC every 3 weeks of decanoate salt

Drug contraindications

Breast feeding , Active liver disease


  • Patients with dementia-related psychosis who are treated with antipsychotic drugs are at increased risk for death, as shown in short-term controlled trials; deaths in these trials appeared to be either cardiovascular (eg, heart failure, sudden death) or infectious (eg, pneumonia) in nature
  • This drug is not approved for treatment of patients with dementia-related psychosis
  • Dermatologic reactions are common
  • Watch for urinary retention, blurred vision, dry mouth, and constipation as result of anticholinergic effects
  • Risk of extrapyramidal symptoms (EPS), NMS, hypotension; hypotension may be particularly severe in patients with pheochromocytoma or mitral insufficiency 
  • May need anticholinergic antiparkinsonian agent to counter EPS; in case of severe hypotension, use norepinephrine or phenylepinephrine, and do not use epinephrine or dopamine
  • Depresses hypothalamic thermoregulatory mechanism; exposure to extreme temperatures may cause hypo- or hyperthermia
  • US Food and Drug Administration (FDA) warning regarding off-label use for dementia in elderly

Points of recommendation

  • Avoid driving and doing other tasks or actions that call for you to be alert until you see how this medicine affects you.
  • Talk with your doctor before you drink alcohol or use other drugs and natural products that slow your actions.
  • You may get sunburned more easily. Avoid sun, sunlamps, and tanning beds. Use sunscreen and wear clothing and eyewear that protects you from the sun.
  • Be careful in hot weather or while being active. Drink lots of fluids to stop fluid loss.
  • If you will be near phosphorus insecticides, talk with your doctor.
  • Low white blood cell counts have happened with drugs like this one. This may lead to a higher chance of getting an infection. Deadly infections have rarely happened. Tell your doctor if you have ever had a low white blood cell count. Call your doctor right away if you have signs of infection like fever, chills, or sore throat.
  • Do not stop taking fluphenazine injection all of a sudden without calling your doctor.
  • Have blood work checked as you have been told by the doctor.
  • This medicine may cause the results of some pregnancy tests to be wrong.
  • If you are 65 or older, use fluphenazine injection with care.

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