Fluphenazine

Fluphenazine is a typical antipsychotic drug used for the treatment of psychoses such as schizophrenia and acute manic phases of bipolar disorder. It belongs to the piperazine class of phenothiazines.

Its main use is as a long acting injection given once every two or three weeks to people with schizophrenia who suffer frequent relapses of illness. Its side effect profile is similar to haloperidol, namely predominantly dopamine-blocking effects which give rise to akathisia, parkinsonism and tremor. Long term side effects include the potentially irreversible tardive dyskinesia and the potentially fatal neuroleptic malignant syndrome.

Pharmacokinetics
Fluphenazine has an incomplete oral bioavailability of 40% to 50% (due to extensive first pass metabolization in the liver). Its half life is 15 to 30 hours.

Dosing
12.5 mg of fluphenazine decanoate is roughly equivalent to 100 mg of zuclopenthixol decanoate or 20 mg of flupentixol decanoate.

Side effects
Notable side effects include akathisia, extrapyramidal side effects, including tardive dyskinesia and Rabbit syndrome. The frequency and severity of extrapyramidal side effects are direct proportional to the dose given and the duration of treatment. Mostly notably, although rare, it can cause hypothermia because it inhibits ability to shiver.

Sedative, allergic-toxic and anticholinergic/sympatholytic side effects are less likely to occur compared with chlorpromazine. The direct deposition of fluphenazine in the cornea and retina has so far not been reported.

Neuroleptic malignant syndrome, although rare, is a potentially lethal side effect of all antipsychotics.

Chemistry
Fluphenazine (4-[3-[2-(trifluoromethyl)phenothiazin-10-yl]propyl]-1-piperazineethanol), is synthesized by any of the methods described already for the preparation of trifluoperazine and related antipsychotics. Alkylation of 2-trifluoromethylphenothiazine using 4-formyl-1-piperazineylpropylchloride in the presence of sodamide synthesizes 2-trifluoromethyl-10-[3-(4-formyl-1-piperazinyl)propyl]phenothiazine. Further alkaline hydrolysis removes the N-formyl group, giving 2-trifluoromethyl-10-[3-(1-piperazinyl)propyl]phenothiazine. This is alkylated by 2-bromoethanol-1 acetate, which upon further acidic hydrolysis removes the protecting acetyl group, yielding fluphenazine.
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