Adverse Reactions Reported at ≥1% Incidence in Double-Blind Placebo-Controlled Clinical Trials with Oral Haloperidol
Adverse reactions occurring in ≥1% of haloperidol-treated patients and at higher rate than placebo in 3 double-blind, parallel, placebo-controlled, clinical trials with the oral formulation are shown in Table 1.
|System/Organ Class Adverse Reaction||Haloperidol (n=284)%||Placebo (n=282)%|
|Nervous System Disorders|
|Extrapyramidal disorder *||50.7||16.0|
Additional Adverse Reactions Reported in Double-Blind, Placebo- or Active Comparator-Controlled Clinical Trials with Injectable or Oral Haloperidol
Additional adverse reactions that are listed below were reported by haloperidol-treated patients in double-blind, active comparator-controlled clinical trials with the injectable or oral formulation, or at <1% incidence in double-blind, parallel, placebo-controlled, clinical trials with the oral formulation.
Cardiac Disorders: Tachycardia
Endocrine Disorders: Hyperprolactinemia
Eye Disorders: Vision blurred
Investigations: Weight increased
Musculoskeletal and Connective Tissue Disorders: Torticollis, Trismus, Muscle rigidity, Muscle twitching
Nervous System Disorders: Akathisia, Dizziness, Dyskinesia, Hypokinesia, Neuroleptic malignant syndrome, Nystagmus, Oculogyric crisis, Parkinsonism, Sedation, Tardive dyskinesia
Psychiatric Disorders: Loss of libido, Restlessness
Reproductive System and Breast Disorders: Amenorrhea, Galactorrhea, Dysmenorrhea, Erectile dysfunction, Menorrhagia, Breast discomfort
Skin and Subcutaneous Tissue Disorders: Acneiform skin reactions
Vascular Disorders: Hypotension, Orthostatic hypotension
The adverse reactions listed below were identified in clinical trials with haloperidol decanoate (long-acting depot formulation), and reflect exposure to the active moiety haloperidol in 410 patients who participated in 13 clinical trials with haloperidol decanoate (15 to 500 mg/month) in the treatment of schizophrenia or schizoaffective disorder. These clinical trials comprised:
- 1 double-blind, active comparator-controlled trial with fluphenazine decanoate.
- 2 trials comparing the decanoate formulation to oral haloperidol.
- 9 open-label trials.
- 1 dose-response trial.
Nervous System Disorders: Akinesia, Cogwheel rigidity, Masked facies.
The following adverse reactions relating to the active moiety haloperidol have been identified during postapproval use of haloperidol or haloperidol decanoate. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Blood and Lymphatic System Disorders: Pancytopenia, Agranulocytosis, Thrombocytopenia, Leukopenia, Neutropenia
Cardiac Disorders: Ventricular fibrillation, Torsade de pointes, Ventricular tachycardia, Extrasystoles
Endocrine Disorders: Inappropriate antidiuretic hormone secretion
Gastrointestinal Disorders: Vomiting, Nausea
General Disorders and Administration Site Conditions: Sudden death, Face edema, Edema, Hyperthermia, Hypothermia
Hepatobiliary Disorders: Acute hepatic failure, Hepatitis, Cholestasis, Jaundice, Liver function test abnormal
Immune System Disorders: Anaphylactic reaction, Hypersensitivity
Investigations: Electrocardiogram QT prolonged, Weight decreased
Metabolic and Nutritional Disorders: Hypoglycemia
Musculoskeletal and Connective Tissue Disorders: Rhabdomyolysis
Nervous System Disorders: Convulsion, Headache, Opisthotonus, Tardive dystonia
Pregnancy, Puerperium and Perinatal Conditions: Drug withdrawal syndrome neonatal
Psychiatric Disorders: Agitation, Confusional state, Depression, Insomnia
Renal and Urinary Disorders: Urinary retention
Reproductive System and Breast Disorders: Priapism, Gynecomastia
Respiratory, Thoracic and Mediastinal Disorders: Laryngeal edema, Bronchospasm, Laryngospasm, Dyspnea
Skin and Subcutaneous Tissue Disorders: Angioedema, Dermatitis exfoliative, Hypersensitivity vasculitis, Photosensitivity reaction, Urticaria, Pruritus, Rash, Hyperhidrosis
In general, the symptoms of overdosage would be an exaggeration of known pharmacologic effects and adverse reactions, the most prominent of which would be: 1) severe extrapyramidal reactions, 2) hypotension, or 3) sedation. The patient would appear comatose with respiratory depression and hypotension which could be severe enough to produce a shock-like state. The extrapyramidal reactions would be manifested by muscular weakness or rigidity and a generalized or localized tremor as demonstrated by the akinetic or agitans types respectively. With accidental overdosage, hypertension rather than hypotension occurred in a two-year old child. The risk of ECG changes associated with torsade de pointes should be considered. (For further information regarding torsade de pointes, please refer to ADVERSE REACTIONS.)
Since there is no specific antidote, treatment is primarily supportive. Dialysis is not recommended in the treatment of overdose because it removes only very small amounts of haloperidol. A patent airway must be established by use of an oropharyngeal airway or endotracheal tube or, in prolonged cases of coma, by tracheostomy. Respiratory depression may be counteracted by artificial respiration and mechanical respirators. Hypotension and circulatory collapse may be counteracted by use of intravenous fluids, plasma, or concentrated albumin, and vasopressor agents such as metaraminol, phenylephrine and norepinephrine. Epinephrine must not be used. In case of severe extrapyramidal reactions, antiparkinson medication should be administered. ECG and vital signs should be monitored especially for signs of QTc interval-prolongation or dysrhythmias and monitoring should continue until the ECG is normal. Severe arrhythmias should be treated with appropriate anti-arrhythmic measures.
In case of an overdose, consult a Certified Poison Control Center (1-800-222-1222).
There is considerable variation from patient to patient in the amount of medication required for treatment. As with all drugs used to treat schizophrenia, dosage should be individualized according to the needs and response of each patient. Dosage adjustments, either upward or downward, should be carried out as rapidly as practicable to achieve optimum therapeutic control.
To determine the initial dosage, consideration should be given to the patient’s age, severity of illness, previous response to other antipsychotic drugs, and any concomitant medication or disease state. Debilitated or geriatric patients, as well as those with a history of adverse reactions to antipsychotic drugs, may require less HALDOL (haloperidol). The optimal response in such patients is usually obtained with more gradual dosage adjustments and at lower dosage levels.
Parenteral medication, administered intramuscularly in doses of 2 to 5 mg, is utilized for prompt control of the acutely agitated schizophrenic patient with moderately severe to very severe symptoms. Depending on the response of the patient, subsequent doses may be given, administered as often as every hour, although 4 to 8 hour intervals may be satisfactory. The maximum dose is 20 mg/day.
Controlled trials to establish the safety and effectiveness of intramuscular administration in children have not been conducted.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
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