HALOPERIDOL DECANOATE: 1,872 Adverse Event Reports & Safety Profile

DESCRIPTION Haloperidol decanoate is the decanoate ester of the butyrophenone, haloperidol decanoate injection. It has a markedly extended duration of effect. It is available in sesame oil in sterile form for intramuscular (IM) injection. The structural formula of haloperidol decanoate, 4-(4-chlorophenyl)-1-[4-(4-fluorophenyl)-4-oxobutyl]-4 piperidinyl decanoate, is: Haloperidol decanoate, USP is a white or almost white powder. It very soluble in alcohol, in methanol and in methylene chloride, practically insoluble in water. Haloperidol decanoate injection is clear, slightly viscous, colorless to pink or amber solution. Each mL of haloperidol decanoate injection for intramuscular injection contains 50 mg haloperidol (present as haloperidol decanoate, USP 70.52 mg) in a sesame oil vehicle, with 1.2% (w/v) benzyl alcohol as a preservative. Each mL of haloperidol decanoate injection for intramuscular injection contains 100 mg haloperidol (present as haloperidol decanoate, USP 141.04 mg) in a sesame oil vehicle, with 1.2% (w/v) benzyl alcohol as a preservative. structural formula of haloperidol decanoate

AND USAGE Haloperidol decanoate injection is indicated for the treatment of schizophrenia in adults who were previously taking a stable dosage of an immediate-release oral haloperidol product. Haloperidol decanoate injection is a typical antipsychotic indicated for the treatment of schizophrenia in adults who were previously taking a stable dosage of an immediate-release oral haloperidol product.

DOSAGE AND ADMINISTRATION Haloperidol decanoate injection, 50 mg (base)/mL and haloperidol decanoate injection, 100 mg (base)/mL should be administered by deep intramuscular injection. A 21 gauge needle is recommended. The maximum volume per injection site should not exceed 3 mL. DO NOT ADMINISTER INTRAVENOUSLY. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Haloperidol decanoate injection, 50 mg (base)/mL and haloperidol decanoate injection, 100 mg (base)/mL are intended for use in schizophrenic patients who require prolonged parenteral antipsychotic therapy. These patients must be previously stabilized on antipsychotic medication before considering a conversion to haloperidol decanoate, USP. Furthermore, it is recommended that patients being considered for haloperidol decanoate, USP therapy have been treated with, and tolerate well, short-acting haloperidol, USP in order to reduce the possibility of an unexpected adverse sensitivity to haloperidol, USP. Close clinical supervision is required during the initial period of dose adjustment in order to minimize the risk of overdosage or reappearance of psychotic symptoms before the next injection. During dose adjustment or episodes of exacerbation of symptoms of schizophrenia, haloperidol decanoate, USP therapy can be supplemented with short-acting forms of haloperidol, USP. The dose of haloperidol decanoate injection, 50 mg (base)/mL or haloperidol decanoate injection, 100 mg (base)/mL should be expressed in terms of its haloperidol, USP content. The starting dose of haloperidol decanoate, USP should be based on the patient's age, clinical history, physical condition, and response to previous antipsychotic therapy. The preferred approach to determining the minimum effective dose is to begin with lower initial doses and to adjust the dose upward as needed. For patients previously maintained on low doses of antipsychotics (e.g. up to the equivalent of 10 mg/day oral haloperidol), it is recommended that the initial dose of haloperidol decanoate, USP be 10-15 times the previous daily dose in oral haloperidol equivalents; limited clinical experience suggests that lower initial doses may be adequate.

Initial Therapy

Conversion from oral haloperidol to haloperidol decanoate, USP can be achieved by using an initial dose of haloperidol decanoate, USP that is 10 to 20 times the previous daily dose in oral haloperidol equivalents. In patients who are elderly, debilitated, or stable on low doses of oral haloperidol (e.g. up to the equivalent of 10 mg/day oral haloperidol), a range of 10 to 15 times the previous daily dose in oral haloperidol equivalents is appropriate for initial conversion. In patients previously maintained on higher doses of antipsychotics for whom a low dose approach risks recurrence of psychiatric decompensation and in patients whose long-term use of haloperidol, USP has resulted in a tolerance to the drug, 20 times the previous daily dose in oral haloperidol equivalents should be considered for initial conversion, with downward titration on succeeding injections. The initial dose of haloperidol decanoate, USP should not exceed 100 mg regardless of previous antipsychotic dose requirements. If, therefore, conversion requires more than 100 mg of haloperidol decanoate, USP as an initial dose, that dose should be administered in two injections, i.e. a maximum of 100 mg initially followed by the balance in 3 to 7 days.

Maintenance Therapy

The maintenance dosage of haloperidol decanoate, USP must be individualized with titration upward or downward based on therapeutic response. The usual maintenance range is 10 to 15 times the previous daily dose in oral haloperidol equivalents dependent on the clinical response of the patient. HALOPERIDOL DECANOATE, USP DOSING RECOMMENDATIONS Patients Monthly 1 st Month Maintenance Stabilized on low daily oral doses (up to 10 mg/day) Elderly or Debilitated 10-15 x Daily Oral Dose 10 -15 x Previous Daily Oral Dose High dose Risk of relapse Tolerant to oral haloperidol 20 x Daily Oral Dose 10 -15 x Previous Daily Oral Dose Close clinical supervision is required during initiation and stabilization of haloperidol decanoate, USP therapy. Haloperidol decanoate, USP is usually administered monthly or every 4 weeks. However, variation in patient response may dictate a need for adjustment of the dosing interval as well as the dose (see CLINICAL PHARMACOLOGY). Clinical experience with haloperidol decanoate, USP at doses greater than 450 mg per month has been limited. Instructions for Opening Ampule Step 1 1. Medication often rests in the top part of the ampule. Before breaking the ampule, lightly tap the top of the ampule with your finger until all fluid moves to the bottom portion of the ampule. The ampule has a colored ring(s) and colored point which aids in the placement of fingers while breaking the ampule.

Step

2 2. Hold the ampule between thumb and index finger with the colored point facing you.

Step

3 3. Position the index finger of the other hand to support the neck of the ampule. Position the thumb so that it covers the colored point and is parallel to the colored ring(s).

Step

4 4. Keeping the thumb on the colored point and with the index fingers clos e together, apply firm pressure on the colored point in the direction of the arrow to snap the ampule open. Step-1 Step-2 Step-3 Step-4

Maintenance Therapy The maintenance dosage of haloperidol decanoate, USP must be individualized with titration upward or downward based on therapeutic response. The usual maintenance range is 10 to 15 times the previous daily dose in oral haloperidol equivalents dependent on the clinical response of the patient. HALOPERIDOL DECANOATE, USP DOSING RECOMMENDATIONS Patients Monthly 1 st Month Maintenance Stabilized on low daily oral doses (up to 10 mg/day) Elderly or Debilitated 10-15 x Daily Oral Dose 10 -15 x Previous Daily Oral Dose High dose Risk of relapse Tolerant to oral haloperidol 20 x Daily Oral Dose 10 -15 x Previous Daily Oral Dose Close clinical supervision is required during initiation and stabilization of haloperidol decanoate, USP therapy. Haloperidol decanoate, USP is usually administered monthly or every 4 weeks. However, variation in patient response may dictate a need for adjustment of the dosing interval as well as the dose (see CLINICAL PHARMACOLOGY). Clinical experience with haloperidol decanoate, USP at doses greater than 450 mg per month has been limited. Instructions for Opening Ampule Step 1 1. Medication often rests in the top part of the ampule. Before breaking the ampule, lightly tap the top of the ampule with your finger until all fluid moves to the bottom portion of the ampule. The ampule has a colored ring(s) and colored point which aids in the placement of fingers while breaking the ampule.

Step

2 2. Hold the ampule between thumb and index finger with the colored point facing you.

Step

3 3. Position the index finger of the other hand to support the neck of the ampule. Position the thumb so that it covers the colored point and is parallel to the colored ring(s).

Step

4 4. Keeping the thumb on the colored point and with the index fingers clos e together, apply firm pressure on the colored point in the direction of the arrow to snap the ampule open. Step-1 Step-2 Step-3 Step-4

CONTRAINDICATIONS Since the pharmacologic and clinical actions of haloperidol decanoate injection, 50 mg /mL and haloperidol decanoate injection, 100 mg/mL are attributed to haloperidol, USP as the active medication, Contraindications, Warnings, and additional information are those of haloperidol, USP, modified only to reflect the prolonged action. Haloperidol is contraindicated in patients with: Severe toxic central nervous system depression or comatose states from any cause. Hypersensitivity to this drug – hypersensitivity reactions have included anaphylactic reaction and angioedema (see WARNINGS, Hypersensitivity Reactions and ADVERSE REACTIONS). Parkinson's disease (see WARNINGS, Neurological Adverse Reactions in Patients with Parkinson's Disease or Dementia with Lewy Bodies). Dementia with Lewy bodies (see WARNINGS, Neurological Adverse Reactions in Patients with Parkinson's Disease or Dementia with Lewy Bodies).

ADVERSE REACTIONS The following adverse reactions are discussed in more detail in other sections of the labeling: WARNINGS, Increased mortality in Elderly Patients with Dementia-Related Psychosis WARNINGS, Cardiovascular Effects WARNINGS, Tardive Dyskinesia WARNINGS, Neuroleptic Malignant Syndrome WARNINGS, Hypersensitivity Reactions WARNINGS, Falls WARNINGS, Combined Use of Haloperidol and Lithium WARNINGS, General PRECAUTIONS, Leukopenia, Neutropenia, and Agranulocytosis PRECAUTIONS, Other PRECAUTIONS, Usage in Pregnancy Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug, and may not reflect the rates observed in practice. The data described below reflect exposure to 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. The most common adverse reactions in haloperidol decanoate-treated patients in the double-blind, active comparator-controlled clinical trial with fluphenazine decanoate (≥5%) were: Parkinsonism, and oculogyric crisis.

Adverse Reactions

Reported at ≥1% Incidence in a Double-Blind Active Comparator-Controlled Clinical Trial Adverse reactions occurring in 1% of haloperidol decanoate-treated patients in a double-blind, clinical trial with the active comparator fluphenazine decanoate are shown in Table 1.

Table

1 .

Adverse Reactions

Reported by ≥1% of Haloperidol Decanoate-treated Patients in a Double- Blind Active Comparator-Controlled Clinical Trial with Fluphenazine Decanoate a Precise incidence for extrapyramidal disorder cannot be determined; reporting rates of some individual symptoms of extrapyramidal disorder are lower for haloperidol decanoate than for the active comparator, but the terms are included here because the events are considered associated with the drug System/Organ Class Adverse Reaction Haloperidol decanoate (n=36) % Fluphenazine decanoate (n=36) % Gastrointestinal Disorders Abdominal pain 2.8 0 Nervous System Disorders Extrapyramidal disorder a : Parkinsonism 30.6

44.4 Oculogyric crisis 5.6 0 Akinesia 2.8

22.2 Akathisia 2.8

13.9 Tremor 2.8 0 Headache 2.8 0 Additional Adverse Reactions Reported in Double-Blind, Comparator, Open-Label and Dose-Response Clinical Trials Additional adverse reactions that are listed below were reported by haloperidol decanoate-treated patients in comparator, open-label, and dose-response clinical trials, or at <1% incidence in a double-blind, active comparator-controlled clinical trial with fluphenazine decanoate.

Cardiac

Disorders: Tachycardia Endocrine Disorders: Hyperprolactinemia Eye Disorders: Vision blurred Gastrointestinal Disorders: Constipation, Dry mouth, Salivary hypersecretion General Disorders and Administration Site Conditions: Injection site reaction Investigations: Weight increased Musculoskeletal and Connective Tissue Disorders: Muscle rigidity Nervous System Disorders: Dyskinesia, Dystonia, Cogwheel rigidity, Hypertonia, Masked Facies, Sedation, Somnolence Reproductive System and Breast Disorders: Erectile dysfunction Adverse Reactions Identified in Clinical Trials with Haloperidol (Non-Decanoate Formulations) The adverse reactions listed below were identified with non-decanoate formulations, and reflect exposure to the active moiety haloperidol in the following: 284 patients who participated in 3 double-blind, placebo-controlled clinical trials with haloperidol (injection or oral formulation, 2 to 20 mg/day); two trials were in the treatment of schizophrenia and one in the treatment of bipolar disorder. 1295 patients who participated in 16 double-blind, active comparator-controlled clinical trials with haloperidol (injection or oral formulation, 1 to 45 mg/day) in the treatment of schizophrenia. Musculoskeletal and Connective Tissue Disorders: Torticollis, Trismus, Muscle twitching Nervous System Disorders: Neuroleptic malignant syndrome, Tardive dyskinesia, Bradykinesia, Hyperkinesia, Hypokinesia, Dizziness, Nystagmus Psychiatric Disorders: Loss of libido, Restlessness Reproductive System and Breast Disorders: Amenorrhea, Galactorrhea, Dysmenorrhea, Menorrhagia, Breast discomfort Skin and Subcutaneous Tissue Disorders: Acneiform skin reactions Vascular Disorders: Hypotension, Orthostatic hypotension Postmarketing Experience 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, Injection site abscess 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, 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, Pruritis, Rash, Hyperhidrosis

Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug, and may not reflect the rates observed in practice. The data described below reflect exposure to 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. The most common adverse reactions in haloperidol decanoate-treated patients in the double-blind, active comparator-controlled clinical trial with fluphenazine decanoate (≥5%) were: Parkinsonism, and oculogyric crisis.

Adverse Reactions

Reported at ≥1% Incidence in a Double-Blind Active Comparator-Controlled Clinical Trial Adverse reactions occurring in 1% of haloperidol decanoate-treated patients in a double-blind, clinical trial with the active comparator fluphenazine decanoate are shown in Table 1.

Table

1 .

Adverse Reactions

Reported by ≥1% of Haloperidol Decanoate-treated Patients in a Double- Blind Active Comparator-Controlled Clinical Trial with Fluphenazine Decanoate a Precise incidence for extrapyramidal disorder cannot be determined; reporting rates of some individual symptoms of extrapyramidal disorder are lower for haloperidol decanoate than for the active comparator, but the terms are included here because the events are considered associated with the drug System/Organ Class Adverse Reaction Haloperidol decanoate (n=36) % Fluphenazine decanoate (n=36) % Gastrointestinal Disorders Abdominal pain 2.8 0 Nervous System Disorders Extrapyramidal disorder a : Parkinsonism 30.6

44.4 Oculogyric crisis 5.6 0 Akinesia 2.8

22.2 Akathisia 2.8

13.9 Tremor 2.8 0 Headache 2.8 0 Additional Adverse Reactions Reported in Double-Blind, Comparator, Open-Label and Dose-Response Clinical Trials Additional adverse reactions that are listed below were reported by haloperidol decanoate-treated patients in comparator, open-label, and dose-response clinical trials, or at <1% incidence in a double-blind, active comparator-controlled clinical trial with fluphenazine decanoate.

Cardiac

Disorders: Tachycardia Endocrine Disorders: Hyperprolactinemia Eye Disorders: Vision blurred Gastrointestinal Disorders: Constipation, Dry mouth, Salivary hypersecretion General Disorders and Administration Site Conditions: Injection site reaction Investigations: Weight increased Musculoskeletal and Connective Tissue Disorders: Muscle rigidity Nervous System Disorders: Dyskinesia, Dystonia, Cogwheel rigidity, Hypertonia, Masked Facies, Sedation, Somnolence Reproductive System and Breast Disorders: Erectile dysfunction Adverse Reactions Identified in Clinical Trials with Haloperidol (Non-Decanoate Formulations) The adverse reactions listed below were identified with non-decanoate formulations, and reflect exposure to the active moiety haloperidol in the following: 284 patients who participated in 3 double-blind, placebo-controlled clinical trials with haloperidol (injection or oral formulation, 2 to 20 mg/day); two trials were in the treatment of schizophrenia and one in the treatment of bipolar disorder. 1295 patients who participated in 16 double-blind, active comparator-controlled clinical trials with haloperidol (injection or oral formulation, 1 to 45 mg/day) in the treatment of schizophrenia. Musculoskeletal and Connective Tissue Disorders: Torticollis, Trismus, Muscle twitching Nervous System Disorders: Neuroleptic malignant syndrome, Tardive dyskinesia, Bradykinesia, Hyperkinesia, Hypokinesia, Dizziness, Nystagmus Psychiatric Disorders: Loss of libido, Restlessness Reproductive System and Breast Disorders: Amenorrhea, Galactorrhea, Dysmenorrhea, Menorrhagia, Breast discomfort Skin and Subcutaneous Tissue Disorders: Acneiform skin reactions Vascular Disorders: Hypotension, Orthostatic hypotension

Postmarketing Experience 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, Injection site abscess 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, 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, Pruritis, Rash, Hyperhidrosis

AND PRECAUTIONS

• Sudden Death, Torsades de Pointes (TdP), and QTc Interval Prolongation : Avoid use of haloperidol decanoate in patients who are at risk of developing TdP. Avoid concomitant use of haloperidol decanoate with drugs that may increase risk of QTc interval prolongation or increase haloperidol exposure. Obtain ECG and serum electrolytes at baseline and during treatment as clinically indicated ( 5.2 ).
• Tachycardia and Hypotension: Monitor orthostatic vital signs ( 5.3 ).
• Cerebrovascular Adverse Reactions Including Stroke in Elderly Patients with Dementia-Related Psychosis: Use with caution in patients with schizophrenia who have risk factors for cerebrovascular adverse reactions ( 5.4 ).
• Tardive Dyskinesia : Discontinue treatment if clinically appropriate ( 5.5 ).
• Neuroleptic Malignant Syndrome (NMS) : Immediately discontinue and monitor closely ( 5.6 ).
• Seizures : Haloperidol decanoate is generally not recommended in patients receiving antiseizure drugs or who have a history of seizures or EEG abnormalities. If clinically, indicated, maintain patients taking haloperidol decanoate on adequate antiseizure therapy ( 5.8 ).
• Potential for Cognitive and Motor Impairment: Advise patients to not drive a motor vehicle or operate hazardous machinery until they are reasonably certain haloperidol decanoate does not impair their cognitive and motor functions ( 5.11 ).
• Risk of Encephalopathic Syndrome with Concomitant Use of Lithium : Monitor closely for early signs of neurological toxicity and discontinue haloperidol decanoate if such signs appear ( 5.12 ).
• Leukopenia, Neutropenia, and Agranulocytosis : Perform complete blood counts (CBC) in patients with pre-existing low white blood cell count (WBC) or history of leukopenia or neutropenia. Consider discontinuing haloperidol decanoate if clinically significant decline in WBC occurs in absence of other causative factors. Discontinue haloperidol decanoate in patients with clinically significant neutropenia or an absolute neutrophile count of <1,000/mm 3 ( 5.13 ).
• Hyperprolactinemia: Elevated prolactin levels may occur during acute and chronic use ( 5.14 ).

5.1 Increased Mortality in Elderly Patients with Dementia-Related Psychosis Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. In an analysis of 17 placebo-controlled trials (modal duration of 10 weeks), largely in patients taking atypical antipsychotic drugs, the risk of death in antipsychotic drug-treated patients was 1.6 to 1.7 times the risk of death in placebo-treated patients. Over the course of a typical 10-week controlled trial, the incidence of death in antipsychotic drug-treated patients was about 4.5%, compared to an incidence of about 2.6% in placebo-treated patients. Although the causes of death were varied, most of the deaths appeared to be either cardiovascular (e.g., heart failure, sudden death) or infectious (e.g., pneumonia) in nature. Haloperidol decanoate is not approved for the treatment of patients with dementia-related psychosis <span class="opacity-50 text-xs">[see Indications and Usage ( 1 )]</span>.

5.2 Sudden Death, Torsades de Pointes, and QTc Interval Prolongation Cases of sudden death, torsades de pointes (TdP) and QTc interval prolongation have been reported in haloperidol-treated patients <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.1 , 6.2 )]</span>. Cases have been reported even in the absence of predisposing factors. Higher than recommended haloperidol dosages were associated with a higher risk of TdP and QTc interval prolongation. Avoid use of haloperidol decanoate in patients who are at significant risk of developing TdP including those with congenital long QT syndrome, uncontrolled or significant cardiac disease, recent myocardial infarction, ischemic cardiomyopathy, unstable angina, bradyarrhythmias, uncontrolled hypertension, high degree atrioventricular block, severe aortic stenosis, or uncontrolled hypothyroidism. Avoid the concomitant use of haloperidol decanoate with drugs that may increase the risk of the QTc interval prolongation or increase haloperidol exposure. Assess the QTc interval via an ECG at baseline, and during treatment as clinically indicated. Obtain serum electrolytes (including potassium, calcium, phosphorus, and magnesium) at baseline and during treatment as clinically indicated, and correct electrolyte abnormalities.

5.3 Tachycardia and Hypotension Tachycardia and hypotension (including orthostatic hypotension) have been reported in patients treated with haloperidol <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.1 )]</span>. Orthostatic vital signs should be monitored in patients who are at risk for hypotension (e.g., geriatric patients, patients with dehydration, hypovolemia, and concomitantly treated with antihypertensive medications), patients with known cardiovascular disease (history of myocardial infarction, ischemic heart disease, heart failure, or conduction abnormalities), and patients with cerebrovascular disease. Should hypotension occur and a vasopressor be required, epinephrine must not be used since haloperidol decanoate may block its vasopressor activity, and paradoxically lower blood pressure. Instead, metaraminol, phenylephrine or norepinephrine should be used.

5.4 Cerebrovascular Adverse Reactions Including Stroke in Elderly Patients with Dementia-Related Psychosis In placebo-controlled trials, elderly patients with dementia-related psychosis treated with antipsychotics had an increased risk of cerebrovascular adverse reactions (e.g., stroke, transient ischemic attack) including fatalities, compared to those treated with placebo. The mechanism for this increased risk is not known. Haloperidol decanoate is not approved for the treatment of patients with dementia-related psychosis. Haloperidol decanoate should be used with caution in patients with schizophrenia who have risk factors for cerebrovascular adverse reactions.

5.5 Tardive Dyskinesia Tardive dyskinesia (TD) may develop in patients treated with antipsychotic drugs, including haloperidol decanoate <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.1 )]</span>. TD can develop after a relatively brief treatment period at low dosages and may also occur after discontinuation of treatment. If antipsychotic treatment is discontinued, TD may partially or completely remit. Antipsychotic treatment, however, may suppress or partially suppress the signs and symptoms of TD and may mask the underlying process. The effect that symptomatic suppression has upon the long-term course of TD is unknown. The TD risk in patients treated with antipsychotic drugs appears to be highest among the elderly, especially elderly women, but it is not possible to predict, which patients are likely to develop TD. The TD risk and the likelihood that TD will become irreversible increase with the duration of antipsychotic drug treatment and the cumulative dosage. In patients who require chronic antipsychotic treatment, use the lowest dosage and the shortest duration of treatment that produces a satisfactory clinical response. Periodically reassess the need for continued treatment. If signs and symptoms of TD appear in haloperidol decanoate-treated patients, consider drug discontinuation. However, some patients may require haloperidol decanoate treatment despite the presence of TD.

5.6 Neuroleptic Malignant Syndrome Neuroleptic Malignant Syndrome (NMS), a potentially fatal symptom complex, has been reported in association with the use of antipsychotic drugs <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.1 )]</span>. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, delirium, and autonomic instability, and additional signs may include elevated creatine phosphokinase, myoglobinuria (rhabdomyolysis), and acute renal failure. If NMS is suspected, immediately discontinue haloperidol decanoate and provide intensive symptomatic treatment and monitoring.

5.7 Neurological Adverse Reactions in Patients with Parkinson’s Disease or Dementia with Lewy Bodies Patients with Parkinson’s disease or Dementia with Lewy bodies may experience increased sensitivity to haloperidol. Manifestations of this increased sensitivity include severe extrapyramidal symptoms (e.g., tremor, rigidity, bradykinesia), confusion, sedation, and falls. Haloperidol decanoate is contraindicated in patients with Dementia with Lewy bodies and in patients with Parkinson’s disease.

5.8 Seizures Haloperidol decanoate may lower the seizure threshold. Haloperidol decanoate is generally not recommended in patients receiving antiseizure drugs or have a history of seizures or EEG abnormalities. If clinically indicated, maintain patients taking haloperidol decanoate on adequate antiseizure therapy.

5.9 Hypersensitivity Reactions There have been postmarketing reports of hypersensitivity reactions with haloperidol including anaphylactic reaction, angioedema, dermatitis exfoliative, hypersensitivity vasculitis, rash, urticaria, face edema, laryngeal edema, bronchospasm, and laryngospasm <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.2 )]</span>. Haloperidol decanoate injection is contraindicated in patients with known hypersensitivity to haloperidol or any components of haloperidol decanoate injection.

5.10 Falls Antipsychotics, including haloperidol decanoate, may cause somnolence, orthostatic hypotension, motor instability and sensory abnormality, which may lead to falls and, consequently, fractures and other injuries. If patients have a condition (or take concomitant drugs) that could exacerbate these effects, complete fall risk assessments when initiating haloperidol decanoate treatment and periodically during long-term treatment.

5.11 Potential for Cognitive and Motor Impairment Haloperidol decanoate may impair judgement, thinking, or motor skills. Inform patients of the risk and advise them to not drive a motor vehicle or operate hazardous machinery until they are reasonably certain that treatment with haloperidol decanoate does not impair their cognitive and motor functions.

5.12 Risk of Encephalopathic Syndrome with Concomitant Use of Lithium An encephalopathic syndrome, characterized by weakness, lethargy, fever, tremulousness, confusion, extrapyramidal symptoms, leukocytosis, and elevated serum enzymes (AST, ALT, GGT, alkaline phosphatase, CK, and LDH), BUN, and fasting blood sugar, followed by irreversible brain damage has occurred in a few patients treated with concomitant haloperidol and lithium. Monitor patients who concomitantly use haloperidol decanoate and lithium closely for early signs of neurological toxicity, and discontinue haloperidol decanoate or both haloperidol decanoate and lithium promptly if such signs appear.

5.13 Leukopenia, Neutropenia, and Agranulocytosis Leukopenia, neutropenia and agranulocytosis (including fatal cases) have been reported during treatment with antipsychotic drugs, including haloperidol decanoate <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.2 )]</span>. Possible risk factors for antipsychotic drug-associated leukopenia and neutropenia include pre-existing low WBC and history of drug-induced leukopenia and neutropenia. Perform frequent complete blood count (CBC) monitoring during the first few months of haloperidol decanoate therapy in patients with a history of a clinically significant low WBC, drug-induced leukopenia or neutropenia. Consider discontinuing haloperidol decanoate in patients who have a clinically significant decline in their WBC in the absence of other causative factors. Discontinue haloperidol decanoate in patients with clinically significant neutropenia or an absolute neutrophil count of &lt;1,000/mm 3 and monitor closely until the neutropenia resolves.

5.14 Hyperprolactinemia Antipsychotic drugs elevate prolactin levels during acute and chronic use and may result in galactorrhea, amenorrhea, gynecomastia, and impotence which have been reported with antipsychotic drugs <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.1 , 6.2 ) and Use in Specific Populations ( 8.3 )]</span>. Published epidemiologic studies have shown inconsistent results regarding the potential association between hyperprolactinemia and breast cancer <span class="opacity-50 text-xs">[see Nonclinical Toxicology ( 13.1 )]</span>.

5.15 Risk of Severe Neurotoxicity in Patients with Thyrotoxicosis Severe neurotoxicity (rigidity, inability to walk or talk) may occur in patients with thyrotoxicosis who are also receiving antipsychotic drugs, including haloperidol decanoate.

PRECAUTIONS Leukopenia, Neutropenia, and Agranulocytosis Class Effect: In clinical trial and/or postmarketing experience, events of leukopenia/neutropenia have been reported temporally related to antipsychotic agents, including haloperidol decanoate. Agranulocytosis has also been reported. Possible risk factors for leukopenia/neutropenia include pre-existing low white blood cell count (WBC) and history of drug-induced leukopenia/neutropenia. Patients with a history of a clinically significant low WBC or a drug-induced leukopenia/neutropenia should have their complete blood count (CBC) monitored frequently during the first few months of therapy and discontinuation of haloperidol decanoate should be considered at the first sign of a clinically significant decline in WBC in the absence of other causative factors. Patients with clinically significant neutropenia should be carefully monitored for fever or other symptoms or signs of infection and treated promptly if such symptoms or signs occur. Patients with severe neutropenia (absolute neutrophil count <1000/mm 3 ) should discontinue haloperidol decanoate and have their WBC followed until recovery.

Other

Haloperidol decanoate injection, 50 mg/mL and haloperidol decanoate injection, 100 mg/mL should be administered cautiously to patients: with severe cardiovascular disorders, because of the possibility of transient hypotension and/or precipitation of anginal pain. Should hypotension occur and a vasopressor be required, epinephrine must not be used since haloperidol may block its vasopressor activity, and paradoxical further lowering of the blood pressure may occur. Instead, metaraminol, phenylephrine or norepinephrine should be used. receiving anticonvulsant medications, with a history of seizures, or with EEG abnormalities, because haloperidol may lower the convulsive threshold. If indicated, adequate anticonvulsant therapy should be concomitantly maintained. with known allergies, or with a history of allergic reactions to drugs. receiving anticoagulants, since an isolated instance of interference occurred with the effects of one anticoagulant (phenindione). Haloperidol may impair the antiparkinson effects of levodopa and other dopamine agonists. If concomitant antiparkinson medication is required, it may have to be continued after haloperidol decanoate injection, 50 mg/mL or haloperidol decanoate injection, 100 mg/mL is discontinued because of the prolonged action of haloperidol decanoate. If both drugs are discontinued simultaneously, extrapyramidal symptoms may occur. The physician should keep in mind the possible increase in intraocular pressure when anticholinergic drugs, including antiparkinson agents, are administered concomitantly with haloperidol decanoate. When haloperidol decanoate is used to control mania in cyclic disorders, there may be a rapid mood swing to depression. Severe neurotoxicity (rigidity, inability to walk or talk) may occur in patients with thyrotoxicosis who are also receiving antipsychotic medication, including haloperidol. Information for patients Haloperidol decanoate may impair the mental and/or physical abilities required for the performance of hazardous tasks such as operating machinery or driving a motor vehicle. The ambulatory patient should be warned accordingly. The use of alcohol with this drug should be avoided due to possible additive effects and hypotension.

Drug Interactions

Drug-drug interactions can be pharmacodynamic (combined pharmacologic e ects) or pharmacokinetic (alteration of plasma levels). The risks of using haloperidol in combination with other drugs have been evaluated as described below.

Pharmacodynamic Interactions

Since QTc interval-prolongation has been observed during Haloperidol treatment, caution is advised when prescribing to a patient with QT-prolongation conditions or to patients receiving medications known to prolong the QTc-interval (see WARNINGS, Cardiovascular Eff ects). Examples include (but are not limited to): Class 1A antiarrhythmics (e.g., procainamide, quinidine, disopyramide); Class 3 antiarrhythmics (e.g., amiodarone, sotalol); and other drugs such as citalopram, erythromycin, levofloxacin, methadone, and ziprasidone. Caution is advised when haloperidol decanoate is used in combination with drugs known to cause electrolyte imbalance (e.g., diuretics or corticosteroids) because hypokalemia, hypomagnesemia, and hypocalcemia are risk factors for QT prolongation. As with other antipsychotic agents, it should be noted that haloperidol may be capable of potentiating CNS depressants such as anesthetics, opioids, and alcohol.

Pharmacokinetic Interactions

Drugs that May Increase Haloperidol Plasma Concentrations Haloperidol is metabolized by several routes. The major pathways are glucuronidation and ketone reduction. The cytochrome P450 enzyme system is also involved, particularly CYP3A4 and, to a lesser extent, CYP2D6. Inhibition of these routes of metabolism by another drug or a decrease in CYP2D6 enzyme may result in increased haloperidol concentrations. The e ffect of CYP3A4 inhibition and of decreased CYP2D6 enzyme activity may be additive. The haloperidol plasma concentrations increased when a CYP3A4 and/or CYP2D6 inhibitor was coadministered with haloperidol. Examples include: CYP3A4 inhibitors – alprazolam; itraconazole, ketoconazole, nefazodone, ritonavir. CYP2D6 inhibitors – chlorpromazine; promethazine; quinidine; paroxetine, sertraline, venlafaxine. Combined CYP3A4 and CYP2D6 inhibitors – fluoxetine, fluvoxamine; ritonavir. Buspirone. Increased haloperidol plasma concentrations may result in an increased risk of adverse events, including QTc interval prolongation (see WARNINGS – Cardiovascular E ects). Increases in QTc have been observed when haloperidol was given with a combination of the metabolic inhibitors ketoconazole (400 mg/day) and paroxetine (20 mg/day). It is recommended that patients who take haloperidol concomitantly with such medicinal products be monitored for signs or symptoms of increased or prolonged pharmacologic eff ects of haloperidol, and the haloperidol decanoate dose be decreased as deemed necessary. Valproate: Sodium valproate, a drug known to inhibit glucuronidation, does not aff ect haloperidol plasma concentrations. Drugs that May Decrease Haloperidol Plasma Concentrations Coadministration of haloperidol with potent enzyme inducers of CYP3A4 may gradually decrease the plasma concentrations of haloperidol to such an extent that efficacy may be reduced. Examples include (but are not limited to: carbamazepine, phenobarbital, phenytoin, rifampin, St John's Wort (Hypericum, perforatum). Rifampin: In a study of 12 patients with schizophrenia coadministered oral haloperidol and rifampin, plasma haloperidol levels were decreased by a mean of 70% and mean scores on the Brief Psychiatric Rating Scale were increased from baseline.

In

5 other patients with schizophrenia treated with oral haloperidol and rifampin, discontinuation of rifampin produced a mean 3.3-fold increase in haloperidol concentrations. Carbamazepine: In a study in 11 patients with schizophrenia coadministered haloperidol and increasing doses of carbamazepine, haloperidol plasma concentrations decreased linearly with increasing carbamazepine concentrations. During combination treatment with inducers of CYP3A4, it is recommended that patients be monitored and the haloperidol decanoate dose increased or the dosage interval adjusted, as deemed necessary. After withdrawal of the CYP3A4 inducer, the concentration of haloperidol may gradually increase and therefore it may be necessary to reduce the dose of haloperidol decanoate, or adjust the dosage interval. E ffect of Haloperidol on Other Drugs Haloperidol is an inhibitor of CYP2D6. Plasma concentrations of CYP2D6 substrates (e,g. tricyclic antidepressants such as desipramine or imipramine) may increase when they are co-administered with haloperidol. Carcinogenesis, Mutagenesis, Impairment of Fertility No mutagenic potential of haloperidol decanoate was found in the Ames Salmonella assay. Negative or inconsistent positive findings have been obtained in in vitro and in vivo studies of e ffects of short-acting haloperidol on chromosome structure and number. The available cytogenetic evidence is considered too inconsistent to be conclusive at this time. Carcinogenicity studies using oral haloperidol were conducted in Wistar rats (dosed at up to 5 mg/kg daily for 24 months) and in Albino Swiss mice (dosed at up to 5 mg/kg daily for 18 months). In the rat study survival was reduced in all dose groups, decreasing the number of rats at risk for developing tumors. However, although a relatively greater number of rats survived to the end of the study in high-dose male and female groups, these animals did not have a greater incidence of tumors than control animals. Therefore, although not optimal, this study does suggest the absence of a haloperidol related increase in the incidence of neoplasia in rats at doses up to approximately 2.5 times the maximum recommended human dose (MRHD) of 20 mg/day based on mg/m2 body surface area. In female mice there was a statistically significant increase in mammary gland neoplasia and total tumor incidence at doses approximately 0.3 and 1.2 times the MRHD based on mg/m2 body surface area and there was a statistically significant increase in pituitary gland neoplasia at approximately 1.2 times the MRHD. In male mice, no statistically significant di fferences in incidences of total tumors or specific tumor types were noted. Antipsychotic drugs elevate prolactin levels; the elevation persists during chronic administration. Tissue culture experiments indicate that approximately one-third of human breast cancers are prolactin dependent in vitro, a factor of potential importance if the prescription of these drugs is contemplated in a patient with a previously detected breast cancer. Although disturbances such as galactorrhea, amenorrhea, gynecomastia, and impotence have been reported, the clinical significance of elevated serum prolactin levels is unknown for most patients. An increase in mammary neoplasms has been found in rodents after chronic administration of antipsychotic drugs. Neither clinical studies nor epidemiologic studies conducted to date, however, have shown an association between chronic administration of these drugs and mammary tumorigenesis; the available evidence is considered too limited to be conclusive at this time. Usage in Pregnancy Rats or rabbits administered oral haloperidol at doses of 0.5 to 7.5 mg/kg, which are approximately 0.2 to 7 times the maximum recommended human dose (MRHD) of 20 mg/day based on mg/m2 body surface area, showed an increase in incidence of resorption, reduced fertility, delayed delivery and pup mortality. No fetal abnormalities were observed at these doses in rats or rabbits. Cleft palate has been observed in mice administered oral haloperidol at a dose of 0.5 mg/kg, which is approximately 0.1 times the MRHD based on mg/m2 body surface area. There are no adequate and well-controlled studies in pregnant women. There are reports, however, of cases of limb malformations observed following maternal use of haloperidol along with other drugs which have suspected teratogenic potential during the first trimester of pregnancy. Causal relationships were not established with these cases. Since such experience does not exclude the possibility of fetal damage due to haloperidol, haloperidol decanoate should be used during pregnancy or in women likely to become pregnant only if the benefit clearly justifies a potential risk to the fetus. Non-Teratogenic Eff ects Neonates exposed to antipsychotic drugs (including haloperidol) during the third trimester of pregnancy are at risk for extrapyramidal and/or withdrawal symptoms following delivery. There have been reports of agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, and feeding disorder in these neonates. These complications have varied in severity; while in some cases symptoms have been self-limited, in other cases neonates have required intensive care unit support and prolonged hospitalization.

Haloperidol

Decanoate should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus .

Nursing Mothers

Since haloperidol is excreted in human breast milk, infants should not be nursed during drug treatment with haloperidol decanoate.

Pediatric Use

Safety and effectiveness of haloperidol decanoate in children have not been established.

Geriatric Use

Clinical studies of haloperidol did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not consistently identified differences in responses between the elderly and younger patients. However, the prevalence of tardive dyskinesia appears to be highest among the elderly, especially elderly women (see WARNINGS, Tardive dyskinesia). Also, the pharmacokinetics of haloperidol in geriatric patients generally warrants the use of lower doses (see DOSAGE AND ADMINISTRATION). Use in Hepatic Impairment Studies in patients with hepatic impairment have not been conducted. Haloperidol concentrations may increase in hepatically impaired patients, because it is primarily metabolized by the liver and protein binding may decrease.

Carcinogenesis, Mutagenesis, Impairment of Fertility No mutagenic potential of haloperidol decanoate was found in the Ames Salmonella assay. Negative or inconsistent positive findings have been obtained in in vitro and in vivo studies of e ffects of short-acting haloperidol on chromosome structure and number. The available cytogenetic evidence is considered too inconsistent to be conclusive at this time. Carcinogenicity studies using oral haloperidol were conducted in Wistar rats (dosed at up to 5 mg/kg daily for 24 months) and in Albino Swiss mice (dosed at up to 5 mg/kg daily for 18 months). In the rat study survival was reduced in all dose groups, decreasing the number of rats at risk for developing tumors. However, although a relatively greater number of rats survived to the end of the study in high-dose male and female groups, these animals did not have a greater incidence of tumors than control animals. Therefore, although not optimal, this study does suggest the absence of a haloperidol related increase in the incidence of neoplasia in rats at doses up to approximately 2.5 times the maximum recommended human dose (MRHD) of 20 mg/day based on mg/m2 body surface area. In female mice there was a statistically significant increase in mammary gland neoplasia and total tumor incidence at doses approximately 0.3 and 1.2 times the MRHD based on mg/m2 body surface area and there was a statistically significant increase in pituitary gland neoplasia at approximately 1.2 times the MRHD. In male mice, no statistically significant di fferences in incidences of total tumors or specific tumor types were noted. Antipsychotic drugs elevate prolactin levels; the elevation persists during chronic administration. Tissue culture experiments indicate that approximately one-third of human breast cancers are prolactin dependent in vitro, a factor of potential importance if the prescription of these drugs is contemplated in a patient with a previously detected breast cancer. Although disturbances such as galactorrhea, amenorrhea, gynecomastia, and impotence have been reported, the clinical significance of elevated serum prolactin levels is unknown for most patients. An increase in mammary neoplasms has been found in rodents after chronic administration of antipsychotic drugs. Neither clinical studies nor epidemiologic studies conducted to date, however, have shown an association between chronic administration of these drugs and mammary tumorigenesis; the available evidence is considered too limited to be conclusive at this time.

Usage in Pregnancy Rats or rabbits administered oral haloperidol at doses of 0.5 to 7.5 mg/kg, which are approximately 0.2 to 7 times the maximum recommended human dose (MRHD) of 20 mg/day based on mg/m2 body surface area, showed an increase in incidence of resorption, reduced fertility, delayed delivery and pup mortality. No fetal abnormalities were observed at these doses in rats or rabbits. Cleft palate has been observed in mice administered oral haloperidol at a dose of 0.5 mg/kg, which is approximately 0.1 times the MRHD based on mg/m2 body surface area. There are no adequate and well-controlled studies in pregnant women. There are reports, however, of cases of limb malformations observed following maternal use of haloperidol along with other drugs which have suspected teratogenic potential during the first trimester of pregnancy. Causal relationships were not established with these cases. Since such experience does not exclude the possibility of fetal damage due to haloperidol, haloperidol decanoate should be used during pregnancy or in women likely to become pregnant only if the benefit clearly justifies a potential risk to the fetus. Non-Teratogenic Eff ects Neonates exposed to antipsychotic drugs (including haloperidol) during the third trimester of pregnancy are at risk for extrapyramidal and/or withdrawal symptoms following delivery. There have been reports of agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, and feeding disorder in these neonates. These complications have varied in severity; while in some cases symptoms have been self-limited, in other cases neonates have required intensive care unit support and prolonged hospitalization.

Haloperidol

Decanoate should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus .

Drug Interactions Drug-drug interactions can be pharmacodynamic (combined pharmacologic effects) or pharmacokinetic (alteration of plasma levels). The risks of using haloperidol in combination with other drugs have been evaluated as described below.

Pharmacodynamic Interactions

Since QTc interval-prolongation has been observed during haloperidol treatment, caution is advised when prescribing to a patient with QT-prolongation conditions or to patients receiving medications known to prolong the QTc-interval (see WARNINGS, Cardiovascular Effects ). Examples include (but are not limited to): Class 1A antiarrhythmics (e.g., procainamide, quinidine, disopyramide); Class 3 antiarrhythmics (e.g., amiodarone, sotalol); and other drugs such as citalopram, erythromycin, levofloxacin, methadone, and ziprasidone. Caution is advised when Haloperidol decanoate is used in combination with drugs known to cause electrolyte imbalance (e.g., diuretics or corticosteroids) because hypokalemia, hypomagnesemia, and hypocalcemia are risk factors for QT prolongation. As with other antipsychotic agents, it should be noted that haloperidol may be capable of potentiating CNS depressants such as anesthetics, opioids, and alcohol.

Pharmacokinetic Interactions

Drugs that May Increase Haloperidol Decanoate Plasma Concentrations Haloperidol is metabolized by several routes. The major pathways are glucuronidation and ketone reduction. The cytochrome P450 enzyme system is also involved, particularly CYP3A4 and, to a lesser extent, CYP2D6. Inhibition of these routes of metabolism by another drug or a decrease in CYP2D6 enzyme may result in increased haloperidol concentrations. The effect of CYP3A4 inhibition and of decreased CYP2D6 enzyme activity may be additive. The haloperidol plasma concentrations increased when a CYP3A4 and/or CYP2D6 inhibitor was coadministered with haloperidol. Examples include: CYP3A4 inhibitors – alprazolam; itraconazole, ketoconazole, nefazodone, ritonavir. CYP2D6 inhibitors – chlorpromazine; promethazine; quinidine; paroxetine, sertraline, venlafaxine. Combined CYP3A4 and CYP2D6 inhibitors – fluoxetine, fluvoxamine; ritonavir. Buspirone. Increased haloperidol plasma concentrations may result in an increased risk of adverse events, including QTc interval prolongation (see WARNINGS – Cardiovascular Effects ). Increases in QTc have been observed when haloperidol was given with a combination of the metabolic inhibitors ketoconazole (400 mg/day) and paroxetine (20 mg/day). It is recommended that patients who take haloperidol concomitantly with such medicinal products be monitored for signs or symptoms of increased or prolonged pharmacologic effects of haloperidol, and the Haloperidol decanoate dose be decreased as deemed necessary. Valproate : Sodium valproate, a drug known to inhibit glucuronidation, does not affect haloperidol plasma concentrations. Drugs that May Decrease Haloperidol Plasma Concentrations Coadministration of haloperidol with potent enzyme inducers of CYP3A4 may gradually decrease the plasma concentrations of haloperidol to such an extent that efficacy may be reduced. Examples include (but are not limited to: carbamazepine, phenobarbital, phenytoin, rifampin, St John's Wort ( Hypericum, perforatum ). Rifampin: In a study of 12 patients with schizophrenia coadministered oral haloperidol and rifampin, plasma haloperidol levels were decreased by a mean of 70% and mean scores on the Brief Psychiatric Rating Scale were increased from baseline.

In

5 other patients with schizophrenia treated with oral haloperidol and rifampin, discontinuation of rifampin produced a mean 3.3-fold increase in haloperidol concentrations. Carbamazepine: In a study in 11 patients with schizophrenia coadministered haloperidol and increasing doses of carbamazepine, haloperidol plasma concentrations decreased linearly with increasing carbamazepine concentrations. During combination treatment with inducers of CYP3A4, it is recommended that patients be monitored and the Haloperidol decanoate dose increased or the dosage interval adjusted, as deemed necessary. After withdrawal of the CYP3A4 inducer, the concentration of haloperidol may gradually increase and therefore it may be necessary to reduce the dose of Haloperidol decanoate, or adjust the dosage interval. Effect of Haloperidol on Other Drugs Haloperidol is an inhibitor of CYP2D6. Plasma concentrations of CYP2D6 substrates (e,g. tricyclic antidepressants such as desipramine or imipramine) may increase when they are co-administered with haloperidol.