Neuroleptic drugs elevate prolactin levels; the elevation persists during chronic administration. Tissue culture experiments indicate that approximately one-third of human breast cancers are prolactin dependent in vitro , a factor of potential importance if the prescription of these drugs is contemplated in a patient with a previously detected breast cancer . Although disturbances such as galactorrhea , amenorrhea , gynecomastia , and impotence have been reported, the clinical significance of elevated serum prolactin levels is unknown for most patients. An increase in mammary neoplasms has been found in rodents after chronic administration of neuroleptic drugs. Neither clinical studies nor epidemiologic studies conducted to date, however, have shown an association between chronic administration of these drugs and mammary tumorigenesis; the available evidence is considered too limited to be conclusive at this time.
Appropriate dosage of Prolixin Decanoate (Fluphenazine Decanoate Injection) should be individualized for each patient and responses carefully monitored. No precise formula can be given to convert to use of Prolixin Decanoate; however, a controlled multicentered study,* in patients receiving oral doses from 5 to 60 mg fluphenazine hydrochloride daily, showed that 20 mg fluphenazine hydrochloride daily was equivalent to 25 mg (1 mL) Prolixin Decanoate every three weeks. This represents an approximate conversion ratio of mL ( mg) of decanoate every three weeks for every 10 mg of fluphenazine hydrochloride daily.