FLUPHENAZINE DECANOATE 25MG/ML INJECTION

Indications

• Schizophrenia
• Other psychotic disorders

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations for paediatric patients.

Adults: Refer to the BNF for specific dosing recommendations for adults.

Mechanism of action

Fluphenazine blocks postsynaptic mesolimbic dopaminergic D1 and D2 receptors in the brain. This action decreases the release of hypothalamic and hypophyseal hormones and is believed to depress the reticular activating system, thus affecting basal metabolism, body temperature, wakefulness, vasomotor tone, and emesis.

Pharmacodynamics

Fluphenazine, as a trifluoro-methyl phenothiazine derivative, is primarily effective in managing schizophrenia and similar psychotic disorders. Its efficacy is linked to its ability to modulate dopaminergic activity in the brain, which is crucial for regulating mood and behavior. However, it has not demonstrated effectiveness in managing behavioral complications associated with mental retardation.

Pharmacokinetics

Fluphenazine is well-absorbed and undergoes extensive metabolism in the liver, with a half-life that can vary significantly among individuals. It is excreted primarily in urine and has active metabolites that contribute to its effects. The pharmacokinetics can be influenced by individual patient factors, including age, liver function, and potential interactions with other medications.

Contra-indications

• Hypersensitivity to fluphenazine or any component of the formulation
• Comatose states
• Severe central nervous system depression
• Bone marrow depression

Adverse effects

• Drowsiness
• Extrapyramidal symptoms (EPS)
• Tardive dyskinesia
• Agranulocytosis
• Hepatotoxicity
• Weight gain
• Anticholinergic effects

Interactions

• May enhance the effects of other CNS depressants
• Antihypertensive agents may have additive effects
• May affect the metabolism of drugs metabolized by CYP450 enzymes

Precautions

• Monitor for signs of agranulocytosis and hepatotoxicity
• Use with caution in patients with a history of seizures
• Caution in elderly patients and those with cardiovascular disease
• Gradual withdrawal is recommended to avoid withdrawal symptoms

Pregnancy

Fluphenazine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is categorized as Pregnancy Category C.

Breast-feeding

Fluphenazine is excreted in breast milk; caution should be exercised when administering to nursing mothers.

Storage

Store at room temperature, away from light and moisture. Keep out of reach of children.

Formulations

• Oral tablets
• Intramuscular injection
• Depot injection

Mechanism of action

Fluphenazine blocks postsynaptic mesolimbic dopaminergic D1 and D2 receptors in the brain; depresses the release of hypothalamic and hypophyseal hormones and is believed to depress the reticular activating system thus affecting basal metabolism, body temperature, wakefulness, vasomotor tone, and emesis. Agranulocytosis and the release of transaminase enzymes from liver cells are known consequences of neuroleptic drug use. These effects are most common with low potency neuroleptic drugs. It has been hypothesized that these effects are due to the direct toxic action of these drugs on blood and liver cells. The purpose of this study is to compare the cytotoxic effects of eight neuroleptic drugs in five different biological test systems. In all of the test systems, thioridazine, chlorpromazine, trifluoperazine, fluphenzine and thiothixene (group one drugs) were the most toxic drugs and molindone was the least toxic. Thioridazine was between 25 and 84 times more toxic than molindone. Loxapine was significantly more toxic than molindone, but less toxic than the group one drugs. Haloperidol was intermediate in toxicity between the group one drugs and loxapine. /It was/ concluded that the difference in cytotoxicity of the neuroleptic drugs observed in these experiments accounts in part for the increase in agranulocytosis and hepatotoxicity with thioridazine and chlorpromazine and for the lower incidence of these side effects with less toxic drugs. The possibility that tardive dyskinesia may be due to the cytotoxic effects of neuroleptic drugs is discussed and an experiment to test this hypothesis is suggested. The principal pharmacologic effects of fluphenazine are similar to those of chlorpromazine. Fluphenazine is more potent on a weight basis than chlorpromazine. Fluphenazine has weak anticholinergic and sedative effects and strong extrapyramidal effects. Fluphenazine has weak antiemetic activity. The development of phenothiazine derivatives as psychopharmacologic agents resulted from the observation that certain phenothiazine antihistaminic compounds produced sedation. In an attempt to enhance the sedative effects of these drugs, promethazine and chlorpromazine were synthesized. Chlorpromazine is the pharmacologic prototype of the phenothiazines. The pharmacology of phenothiazines is complex, and because of their actions on the central and autonomic nervous systems, the drugs affect many different sites in the body. Although the actions of the various phenothiazines are generally similar, these drugs differ both quantitatively and qualitatively in the extent to which they produce specific pharmacologic effects. /Phenothiazine General Statement/ In the CNS, phenothiazines act principally at the subcortical levels of the reticular formation, limbic system, and hypothalamus. Phenothiazines generally do not produce substantial cortical depression; however, there is minimal information on the specific effects of phenothiazines at the cortical level. Phenothiazines also act in the basal ganglia, exhibiting extrapyramidal effects. The precise mechanism(s) of action, including antipsychotic action, of phenothiazines has not been determined, but may be principally related to antidopaminergic effects of the drugs. There is evidence to indicate that phenothiazines antagonize dopamine-mediated neurotransmission at the synapses. There is also some evidence that phenothiazines may block postsynaptic dopamine receptor sites. However, it has not been determined whether the antipsychotic effect of the drugs is causally related to their antidopaminergic effects. Phenothiazines also have peripheral and/or central antagonistic activity against alpha-adrenergic, serotonergic, histaminic (H1-receptors), and muscarinic receptors. Phenothiazines also have some adrenergic activity, since they block the reuptake of monoamines at the presynaptic neuronal membrane, which tends to enhance neurotransmission. The effects of phenothiazines on the autonomic nervo

Pharmacodynamics

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.