SIDE EFFECTS
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 (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 (perphenazine) .
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 (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.