Professional Information — Perphenazine

Indications and Usage

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 and Administration

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. Optimal clinical effect or benefit may require lower doses for a longer duration. Dosing of perphenazine may occur before bedtime, if required.

Manifestations

The toxic effects of perphenazine are typically mild to moderate with death occurring in cases involving a large overdose. Overdosage of perphenazine primarily involves the extrapyramidal mechanism and produces the same side effects described under ADVERSE REACTIONS, but to a more marked degree. It is usually evidenced by stupor or coma; children may have convulsive seizures. Signs of arousal may not occur for 48 hours. The primary effects of medical concern are cardiac in origin including tachycardia, prolongation of the QRS or QTc intervals, atrioventricular block, torsade de pointes, ventricular dysrhythmia, hypotension or cardiac arrest, which indicate serious poisoning. Deaths by deliberate or accidental overdosage have occurred with this class of drugs.

Treatment

Treatment is symptomatic and supportive. Induction of emesis is not recommended because of the possibility of a seizure, CNS depression, or dystonic reaction of the head or neck and subsequent aspiration. Gastric lavage (after intubation, if the patient is unconscious) and administration of activated charcoal together with a laxative should be considered. There is no specific antidote.

Standard measures (oxygen, intravenous fluids, corticosteroids) should be used to manage circulatory shock or metabolic acidosis. An open airway and adequate fluid intake should be maintained. Body temperature should be regulated. Hypothermia is expected, but severe hyperthermia may occur and must be treated vigorously. (See CONTRAINDICATIONS.)

An electrocardiogram should be taken and close monitoring of cardiac function instituted if there is any sign of abnormality. Close monitoring of cardiac function is advisable for not less than five days. Vasopressors such as norepinephrine may be used to treat hypotension, but epinephrine should NOT be used.

Hemodialysis and peritoneal dialysis is of no value because of low plasma concentrations of the drug.

Since overdosage is often deliberate, patients may attempt suicide by other means during the recovery phase.

Contraindications

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.

Perphenazine products are also contraindicated in patients with suspected or established subcortical brain damage, with or without hypothalamic damage, since a hyperthermic reaction with temperatures in excess of 104°F may occur in such patients, sometimes not until 14 to 16 hours after drug administration. Total body ice-packing is recommended for such a reaction; antipyretics may also be useful.

Adverse Reactions

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.

CNS Effects

Extrapyramidal Reactions

opisthotonus, trismus, torticollis, retrocollis, aching and numbness of the limbs, motor restlessness, oculogyric crisis, hyperreflexia, dystonia, including protrusion, discoloration, aching and rounding of the tongue, tonic spasm of the masticatory muscles, tight feeling in the throat, slurred speech, dysphagia, akathisia, dyskinesia, parkinsonism, and ataxia. Their incidence and severity usually increase with an increase in dosage, but there is considerable individual variation in the tendency to develop such symptoms. Extrapyramidal symptoms can usually be controlled by the concomitant use of effective antiparkinsonian drugs, such as benztropine mesylate, and/or by reduction in dosage. In some instances, however, these extrapyramidal reactions may persist after discontinuation of treatment with perphenazine.

Dystonia

Class effect: Symptoms of dystonia, prolonged abnormal contractions of muscle groups, may occur in susceptible individuals during the first few days of treatment. Dystonic symptoms include: spasm of the neck muscles, sometimes progressing to tightness of the throat, swallowing difficulty, difficulty breathing, and/or protrusion of the tongue. While these symptoms can occur at low doses, they occur more frequently and with greater severity with high potency and at higher doses of first generation antipsychotic drugs. An elevated risk of acute dystonia is observed in males and younger age groups.

Persistent Tardive Dyskinesia

As with all antipsychotic agents, tardive dyskinesia may appear in some patients on long- term therapy or may appear after drug therapy has been discontinued. Although the risk appears to be greater in elderly patients on high-dose therapy, especially females, it may occur in either sex and in children. The symptoms are persistent and in some patients appear to be irreversible. The syndrome is characterized by rhythmical, involuntary movements of the tongue, face, mouth or jaw (e.g., protrusion of tongue, puffing of cheeks, puckering of mouth, chewing movements). Sometimes these may be accompanied by involuntary movements of the extremities. There is no known effective treatment for tardive dyskinesia; antiparkinsonism agents usually do not alleviate the symptoms of this syndrome. It is suggested that all antipsychotic agents be discontinued if these symptoms appear. Should it be necessary to reinstitute treatment, or increase the dosage of the agent, or switch to a different antipsychotic agent, the syndrome may be masked. It has been reported that fine, vermicular movements of the tongue may be an early sign of the syndrome, and if the medication is stopped at that time the syndrome may not develop.

Other CNS Effects

include cerebral edema; abnormality of cerebrospinal fluid proteins; convulsive seizures, particularly in patients with EEG abnormalities or a history of such disorders; and headaches.

Neuroleptic malignant syndrome has been reported in patients treated with antipsychotic drugs (see WARNINGS).

Drowsiness may occur, particularly during the first or second week, after which it generally disappears. If troublesome, lower the dosage. Hypnotic effects appear to be minimal, especially in patients who are permitted to remain active.

Adverse behavioral effects include paradoxical exacerbation of psychotic symptoms, catatonic-like states, paranoid reactions, lethargy, paradoxical excitement, restlessness, hyperactivity, nocturnal confusion, bizarre dreams, and insomnia.

Hyperreflexia has been reported in the newborn when a phenothiazine was used during pregnancy.

Autonomic Effects

dry mouth or salivation, nausea, vomiting, diarrhea, anorexia, constipation, obstipation, fecal impaction, urinary retention, frequency or incontinence, bladder paralysis, polyuria, nasal congestion, pallor, myosis, mydriasis, blurred vision, glaucoma, perspiration, hypertension, hypotension, and change in pulse rate occasionally may occur. Significant autonomic effects have been infrequent in patients receiving less than 24 mg perphenazine daily.

Adynamic ileus occasionally occurs with phenothiazine therapy, and if severe, can result in complications and death. It is of particular concern in psychiatric patients, who may fail to seek treatment of the condition.

Allergic Effects

urticaria, erythema, eczema, exfoliative dermatitis, pruritus, photosensitivity, asthma, fever, anaphylactoid reactions, laryngeal edema, and angioneurotic edema; contact dermatitis in nursing personnel administering the drug; and in extremely rare instances, individual idiosyncrasy or hypersensitivity to phenothiazines has resulted in cerebral edema, circulatory collapse, and death.

Endocrine Effects

lactation, galactorrhea, moderate breast enlargement in females and gynecomastia in males on large doses, disturbances in the menstrual cycle, amenorrhea, changes in libido, inhibition of ejaculation, syndrome of inappropriate ADH (antidiuretic hormone) secretion, false positive pregnancy tests, hyperglycemia, hypoglycemia, glycosuria.

Cardiovascular Effects

postural hypotension, tachycardia (especially with sudden marked increase in dosage), bradycardia, cardiac arrest, faintness, and dizziness. Occasionally the hypotensive effect may produce a shock-like condition. ECG changes, nonspecific (quinidine-like effect) usually reversible, have been observed in some patients receiving phenothiazine antipsychotics.

Sudden death has occasionally been reported in patients who have received phenothiazines. In some cases, the death was apparently due to cardiac arrest; in others, the cause appeared to be asphyxia due to failure of the cough reflex. In some patients, the cause could not be determined nor could it be established that the death was due to the phenothiazine.

Hematological Effects

agranulocytosis, eosinophilia, leukopenia, hemolytic anemia, thrombocytopenic purpura, and pancytopenia. Most cases of agranulocytosis have occurred between the fourth and tenth weeks of therapy. Patients should be watched closely, especially during that period, for the sudden appearance of sore throat or signs of infection. If white blood cell and differential cell counts show significant cellular depression, discontinue the drug and start appropriate therapy. However, a slightly lowered white count is not in itself an indication to discontinue the drug.

Other Effects

Special considerations in long-term therapy include pigmentation of the skin, occurring chiefly in the exposed areas; ocular changes consisting of deposition of fine particulate matter in the cornea and lens, progressing in more severe cases to star-shaped lenticular opacities; epithelial keratopathies; and pigmentary retinopathy. Also noted: peripheral edema, reversed epinephrine effect, increase in PBI not attributable to an increase in thyroxine, parotid swelling (rare), hyperpyrexia, systemic lupus erythematosus-like syndrome, increases in appetite and weight, polyphagia, photophobia, and muscle weakness.

Liver damage (biliary stasis) may occur. Jaundice may occur, usually between the second and fourth weeks of treatment, and is regarded as a hypersensitivity reaction. Incidence is low. The clinical picture resembles infectious hepatitis but with laboratory features of obstructive jaundice. It is usually reversible; however, chronic jaundice has been reported.

Drug Interactions

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. In one study of 45 elderly patients suffering from dementia treated with perphenazine, the 5 patients who were prospectively identified as poor P450 2D6 metabolizers had reported significantly greater side effects during the first 10 days of treatment than the 40 extensive metabolizers, following which the groups tended to converge. Prospective phenotyping of elderly patients prior to antipsychotic treatment may identify those at risk for adverse events.

The concomitant administration of other drugs that inhibit the activity of P450 2D6 may acutely increase plasma concentrations of antipsychotics. Among these are tricyclic antidepressants and selective serotonin reuptake inhibitors, e.g., fluoxetine, sertraline and paroxetine. When prescribing these drugs to patients already receiving antipsychotic therapy, close monitoring is essential and dose reduction may become necessary to avoid toxicity. Lower doses than usually prescribed for either the antipsychotic or the other drug may be required.

Overdosage

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.

Description

Perphenazine (4-[3-(2-chlorophenothiazin-10-yl)propyl]-1-piperazineethanol), a piperazinyl phenothiazine, having the molecular formula, C₂₁H₂₆CIN₃OS. It is available as oral tablets containing 2 mg, 4 mg, 8 mg, and 16 mg of perphenazine. Its structural formula is:

Perphenazine is a white or yellowish-white crystalline powder. It is practically insoluble in water; freely soluble in alcohol and in chloroform; soluble in acetone.

Each film-coated perphenazine tablet intended for oral administration contains 2 mg, 4 mg, 8 mg and 16 mg of perphenazine. In addition, each tablet contains the following inactive ingredients: corn starch, hydroxypropyl cellulose, lactose monohydrate, magnesium stearate and microcrystalline cellulose. Additionally, each film-coated perphenazine tablet contains opadry II white 03B28796 which contains hypromellose, polyethylene glycol and titanium dioxide.

Clinical Pharmacology

Perphenazine has actions at all levels of the central nervous system, particularly the hypothalamus. However, the site and mechanism of action of therapeutic effect are not known.

Pharmacokinetics

Following oral administration of perphenazine tablets, mean peak plasma perphenazine concentrations were observed between 1 to 3 hours. The plasma elimination half-life of perphenazine was independent of dose and ranged between 9 and 12 hours. In a study in which normal volunteers (n=12) received perphenazine 4 mg q8h for 5 days, steady-state concentrations of perphenazine were reached within 72 hours. Mean (%CV) C_max and C_min values for perphenazine and 7-hydroxyperphenazine at steady-state are listed below:

Peak 7-hydroxyperphenazine concentrations were observed between 2 to 4 hours with a terminal phase half-life ranging between 9.9 to 18.8 hours. Perphenazine is extensively metabolized in the liver to a number of metabolites by sulfoxidation, hydroxylation, dealkylation, and glucuronidation. The pharmacokinetics of perphenazine covary with the hydroxylation of debrisoquine which is mediated by cytochrome P450 2D6 (CYP 2D6) and thus is subject to genetic polymorphism – i.e., 7% to 10% of Caucasians and a low percentage of Asians have little or no activity and are called "poor metabolizers." Poor metabolizers of CYP 2D6 will metabolize perphenazine more slowly and will experience higher concentrations compared with normal or "extensive" metabolizers.

How Supplied / Storage and Handling

Perphenazine Tablets USP, 2 mg are white to off white, round, biconvex, film coated tablet debossed with '5' on one side and '91' on other side and are supplied as follows:

NDC 70771-1041-1 in bottles of 100 tablets

NDC 70771-1041-5 in bottles of 500 tablets

NDC 70771-1041-4 in unit-dose blister cartons of 100 (10 x 10) unit-dose tablets

Perphenazine Tablets USP, 4 mg are white to off white, round, biconvex, film coated tablet debossed with '592' on one side and plain on other side and are supplied as follows:

NDC 70771-1042-1 in bottles of 100 tablets

NDC 70771-1042-5 in bottles of 500 tablets

NDC 70771-1042-4 in unit-dose blister cartons of 100 (10 x 10) unit-dose tablets

Perphenazine Tablets USP, 8 mg are white to off white, round, biconvex, film coated tablet debossed with '593' on one side and plain on other side and are supplied as follows:

NDC 70771-1043-1 in bottles of 100 tablets

NDC 70771-1043-5 in bottles of 500 tablets

NDC 70771-1043-4 in unit-dose blister cartons of 100 (10 x 10) unit-dose tablets

Perphenazine Tablets USP, 16 mg are white to off white, round, biconvex, film coated tablet debossed with '594' on one side and plain on other side and are supplied as follows:

NDC 70771-1044-1 in bottles of 100 tablets

NDC 70771-1044-5 in bottles of 500 tablets

NDC 70771-1044-4 in unit-dose blister cartons of 100 (10 x 10) unit-dose tablets

Storage

Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature].

Dispense in a tight, light-resistant container (USP).

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Manufactured by:

Zydus Lifesciences Ltd., Baddi, India

Rev.: 11/24

Patient Counseling Information

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.