List of products in the National Drug Code with proprietary name . This medication is a long-acting form of fluphenazine that is used to treat certain mental/mood problems (chronic schizophrenia). Fluphenazine decanoate is usually used in patients who have benefited from regular doses of short-acting forms of fluphenazine and who may benefit from long-term (maintenance) treatment with less frequent dosing. Fluphenazine belongs to a class of medications called phenothiazines and is also referred to as a neuroleptic. It works by affecting the balance of natural chemicals (neurotransmitters) in the brain. Some of the benefits of continued use of this medication include reduced episodes of hallucinations, delusions, or bizarre behaviors that occur in patients with schizophrenia. This product does not work right away. It may take 1-3 days to notice an effect from this drug, and up to 4 days to experience the full effect. For severe agitation or other symptoms, use a short-acting medication as directed by your doctor. This medication is not recommended for use in children under 12 years of age. Also, it should not be used to manage behavioral problems in patients with mental retardation.