Perphenazine

Perphenazine tablets, USP are indicated for use in the treatment of schizophrenia and for the control of severe nausea and vomiting in adults. Perphenazine tablets, USP have not been shown effective for the management of behavioral complications in patients with mental retardation.

• Dosage must be individualized and adjusted according to the severity of the condition and the response obtained
• As with all potent drugs, the best dose is the lowest dose that will produce the desired clinical effect
• Since extrapyramidal symptoms increase in frequency and severity with increased dosage, it is important to employ the lowest effective dose
• These symptoms have disappeared upon reduction of dosage, withdrawal of the drug, or administration of an antiparkinsonian agent
• Prolonged administration of doses exceeding 24 mg daily should be reserved for hospitalized patients or patients under continued observation for early detection and management of adverse reactions
• An antiparkinsonian agent, such as trihexyphenidyl hydrochloride or benztropine mesylate, is valuable in controlling drug-induced extrapyramidal symptoms
• Suggested dosages for various conditions follow: Moderately disturbed nonhospitalized patients with schizophrenia 4 mg to 8 mg three times daily initially; reduce as soon as possible to minimum effective dosage
• Hospitalized patients with schizophrenia 8 mg to 16 mg two times daily to four times daily; avoid dosages in excess of 64 mg daily
• Severe nausea and vomiting
• In adults 8 mg to 16 mg daily in divided doses; 24 mg occasionally may be necessary; early dosage reduction is desirable
• Elderly Patients With increasing age, plasma concentrations of perphenazine per daily ingested dose increase
• Geriatric dosages of perphenazine preparations have not been established, but initiation of lower dosages is recommended. …

Clinical studies of perphenazine products did not include sufficient numbers of subjects aged 65 and over to determine whether elderly subjects respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. …

• This information is intended to aid in the safe and effective use of this medication
• It is not a disclosure of all possible adverse or intended effects
• Given the likelihood that a substantial proportion of patients exposed chronically to antipsychotics will develop tardive dyskinesia, it is advised that all patients in whom chronic use is contemplated be given, if possible, full information about this risk
• The decision to inform patients and/or their guardians must obviously take into account the clinical circumstances and the competency of the patient to understand the information provided

Perphenazine products are contraindicated in comatose or greatly obtunded patients and in patients receiving large doses of central nervous system depressants (barbiturates, alcohol, narcotics, analgesics, or antihistamines); in the presence of existing blood dyscrasias, bone marrow depression, or liver damage; and in patients who have shown hypersensitivity to perphenazine products, their components, or related compounds. …

Metabolism of a number of medications, including antipsychotics, antidepressants, ß- blockers, and antiarrhythmics, occurs through the cytochrome P450 2D6 isoenzyme (debrisoquine hydroxylase). Approximately 10% of the Caucasian population has reduced activity of this enzyme, so-called "poor" metabolizers. Among other populations the prevalence is not known. Poor metabolizers demonstrate higher plasma concentrations of antipsychotic drugs at usual doses, which may correlate with emergence of side effects. …

Increased Mortality in Elderly Patients with Dementia-Related Psychosis Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Perphenazine tablets, USP are not approved for the treatment of patients with dementia-related psychosis ( see BOXED WARNING ). Tardive dyskinesia, a syndrome consisting of potentially irreversible, involuntary, dyskinetic movements, may develop in patients treated with antipsychotic drugs. Older patients are at increased risk for development of tardive dyskinesia. …

Not all of the following adverse reactions have been reported with this specific drug; however, pharmacological similarities among various phenothiazine derivatives require that each be considered. With the piperazine group (of which perphenazine is an example), the extrapyramidal symptoms are more common, and others (e.g., sedative effects, jaundice, and blood dyscrasias) are less frequently seen. …

In the event of overdosage, emergency treatment should be started immediately. Consultation with a poison center should be considered. All patients suspected of having taken an overdose should be hospitalized as soon as possible.

تناولها عندما تتذكر، إلا إذا اقترب موعد الجرعة التالية. عندها تخطَّ الجرعة المنسية. لا تتناول جرعتين معًا أبدًا للتعويض. راجع النشرة، فبعض الأدوية مختلفة.