Drowsiness,
dizziness, amenorrhea, blurred vision, skin reactions and hypotension
may occur. Neuroleptic Malignant Syndrome (NMS) has been reported in
association with antipsychotic drugs (see WARNINGS).
Cholestatic
jaundice has occurred. If fever with grippe-like symptoms occurs,
appropriate liver studies should be conducted. If tests indicate an
abnormality, stop treatment. There have been a few observations of
fatty changes in the livers of patients who have died while receiving
the drug. No causal relationship has been established.
Leukopenia
and agranulocytosis have occurred. Warn patients to report the sudden
appearance of sore throat or other signs of infection. If white blood
cell and differential counts indicate leukocyte depression, stop
treatment and start antibiotic and other suitable therapy.
Neuromuscular (Extrapyramidal) Reactions
These
symptoms are seen in a significant number of hospitalized mental
patients. They maybe characterized by motor restlessness, be of the
dystonic type, or they may resemble parkinsonism.
Depending on
the severity of symptoms, dosage should be reduced or discontinued. If
therapy is reinstituted, it should be at a lower dosage. Should these
symptoms occur in children or pregnant patients, the drug should be
stopped and not reinstituted. In most cases barbiturates by suitable
route of administration will suffice. (Or, injectable Benadryl®ll
may be useful). In more severe cases, the administration of an
anti-parkinsonism agent, except levodopa (See PDR), usually produces
rapid reversal of symptoms. Suitable supportive measures such as
maintaining a clear airway and adequate hydration should be employed.
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.
These usually subside within a few hours, and almost always within 24 to 48 hours, after the drug has been discontinued.
Motor Restlessness: Symptoms
may include agitation or jitteriness and sometimes insomnia. These
symptoms often disappear spontaneously. At times these symptoms may be
similar to the original neurotic or psychotic symptoms. Dosage should
not be increased until these side effects have subsided.
If
these symptoms become too troublesome, they can usually be controlled
by a reduction of dosage or change of drug. Treatment with
anti-parkinsonian agents, benzodiazepines or propranolol may be helpful.
Pseudo-Parkinsonism: Symptoms
may include: mask-like facies; drooling; tremors; pillrolling motion;
cog-wheel rigidity; and shuffling gait. Reassurance and sedation are
important. In most cases these symptoms are readily controlled when an
anti-parkinsonism agent is administered concomitantly. Anti-
parkinsonism agents should be used only when required. Generally,
therapy of a few weeks to 2 or 3 months will suffice. After this time
patients should be evaluated to determine their need for continued
treatment. (Note: Levodopa has not been found effective in
pseudo-parkinsonism). Occasionally it is necessary to lower the dosage
of prochlorperazine or to discontinue the drug.
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. The syndrome can also develop, although much less
frequently, after relatively brief treatment periods at low doses. This
syndrome appears in all age groups. Although its prevalence appears to
be highest among elderly patients, especially elderly women, it is
impossible to rely upon prevalence estimates to predict at the
inception of antipsychotic treatment which patients are likely to
develop the syndrome. 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 extremities. In rare instances, these involuntary movements of the
extremities are the only manifestations of tardive dyskinesia. A
variant of tardive dyskinesia, tardive dystonia, has also been
described.
There is no known effective treatment for tardive
dyskinesia; anti-parkinsonism agents 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.
Adverse Reactions Reported with Prochlorperazine or Other Phenothiazine Derivatives:
Adverse
reactions with different phenothiazines vary in type, frequency and
mechanism of occurrence, i.e., some are dose-related, while others
involve individual patient sensitivity. Some adverse reactions may be
more likely to occur, or occur with greater intensity, in patients with
special medical problems, e.g., patients with mitral insufficiency or
pheochromocytoma have experienced severe hypotension following
recommended doses of certain phenothiazines.
Not all of the
following adverse reactions have been observed with every phenothiazine
derivative, but they have been reported with 1 or more and should be
borne in mind when drugs of this class are administered: extrapyramidal
symptoms (opisthotonos, oculogyric crisis, hyperreflexia, dystonia,
akathisia, dyskinesia, parkinsonism) some of which have lasted months
and even years-particularly in elderly patients with previous brain
damage; grand mal and petit mal convulsions, particularly in patients
with EEG abnormalities or history of such disorders; altered
cerebrospinal fluid proteins; cerebral edema; intensification and
prolongation of the action of central nervous system depressants
(opiates, analgesics, antihistamines, barbiturates, alcohol), atropine,
heat, organophosphorus insecticides; autonomic reactions (dryness of
mouth, nasal congestion, headache, nausea, constipation, obstipation,
adynamic ileus, ejaculatory disorders/impotence, priapism, atonic
colon, urinary retention, miosis and mydriasis); reactivation of
psychotic processes, catatonic-like states; hypotension (sometimes
fatal); cardiac arrest; blood dyscrasias (pancytopenia,
thrombocytopenic purpura, leukopenia, agranulocytosis, eosinophilia,
hemolytic anemia, aplastic anemia); liver damage (jaundice, biliary
stasis); endocrine disturbances (hyperglycemia, hypoglycemia,
glycosuria, lactation, galactorrhea, gynecomastia, menstrual
irregularities, false-positive pregnancy tests); skin disorders
(photosensitivity, itching, erythema, urticaria, eczema up to
exfoliative dermatitis); other allergic reactions (asthma, laryngeal
edema, angioneurotic edema, anaphylactoid reactions); peripheral edema;
reversed epinephrine effect; hyperpyrexia; mild fever after large I.M.
doses; increased appetite; increased weight; a systemic lupus
erythematosus-like syndrome; pigmentary retinopathy; with prolonged
administration of substantial doses, skin pigmentation, epithelial
keratopathy, and lenticular and corneal deposits.
EKG changes-
particularly nonspecific, usually reversible Q and T wave
distortions-have been observed in some patients receiving phenothiazine.
Although
phenothiazines cause neither psychic nor physical dependence, sudden
discontinuance in long-term psychiatric patients may cause temporary
symptoms, e.g., nausea and vomiting, dizziness, tremulousness. NOTE:
There have been occasional reports of sudden death in patients
receiving phenothiazines. In some cases, the cause appeared to be
cardiac arrest or asphyxia due to failure of the cough reflex.