Adverse Reactions Reported with Prochlorperazine
or other Phenothiazine Derivatives: Drowsiness, dizziness, amenorrhea,
blurred vision, skin reactions and hypotension may occur.
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)
ReactionsThese symptoms are seen in a significant number of hospitalized
mental patients. They may be 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 diphenhydramine 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.
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.
Extrapyramidal Symptoms
DystoniaClass 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.
Pseudo-parkinsonism: Symptoms may include: mask-like
faces; drooling; tremors; pillrolling motion; cogwheel 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 two or three months will suffice. After
this time patients should be evaluated to determine their need for continued
treatment. (Note: norepinephrine bitartrate 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 neuroleptic
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 one 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 statis); 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
tranquilizers.
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.