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Medications: Seroquel® – quetiapine

MEDICATIONS

Seroquel® – quetiapine (View the FDA label)

SEROQUEL can be taken with or without food (2.1)

Indication Initial Dose Recommended
Dose
Maximum
Dose
Schizophrenia-Adults (2.2) 25 mg twice daily 150-175 mg/day 750 mg/day
Schizophrenia-Adolescents (13-17 years) (2.2) 25 mg twice daily 400-800 mg/day 800 mg/day
Bipolar Mania-Adults Monotherapy or as an adjust to lithium or divalproex (2.2) 50 mg twice daily 400-800 mg/day 800 mg/day
Bipolar Mania-Children and Adolescents (10-17 years), Monotherapy (2.2) 25 mg twice daily 400-600 mg/day 600 mg/day
Bipolar Depression-Adults (2.2) 50 mg once daily at bedrime 300 mg/day 300 mg/day

Geriatric Use: Consider a lower starting dose (50 mg/day), slower titration and careful monitoring during the initial dosing period in the elderly (2.3, 8.5)

Hepatic Impairment: Lower starting dose (25 mg/day) and slower titration may be needed (2.4, 8.7, 12.3)

Most common adverse reactions (incidence ≥5% and twice placebo):

Adults: somnolence, dry mouth, dizziness, constipation, asthenia, abdominal pain, postural hypotension, pharyngitis, weight gain, lethargy, ALT increased, dyspepsia (6.1)

Children and Adolescents: somnolence, dizziness, fatigue, increased appetite, nausea, vomiting, dry mouth, tachycardia, weight increased (6.1)

Cerebrovascular Adverse Reactions: Increased incidence of cerebrovascular adverse events (e.g., stroke, transient ischemic attack) has been seen in elderly patients with dementia-related psychoses treated with atypical antipsychotic drugs (5.3)

Neuroleptic Malignant Syndrome (NMS): Manage with immediate discontinuation and close monitoring (5.4)

Metabolic Changes: Atypical antipsychotics have been associated with metabolic changes. These metabolic changes include hyperglycemia, dyslipidemia, and weight gain (5.5)

  • Hyperglycemia and Diabetes Mellitus: Monitor patients for symptoms of hyperglycemia including polydipsia, polyuria, polyphagia, and weakness. Monitor glucose regularly in patients with diabetes or at risk for diabetes
  • Dyslipidemia: Undesirable alterations have been observed in patients treated with atypical antipsychotics. Appropriate clinical monitoring is recommended, including fasting blood lipid testing at the beginning of, and periodically, during treatment
  • Weight Gain: Gain in body weight has been observed; clinical monitoring of weight is recommended

Tardive Dyskinesia: Discontinue if clinically appropriate (5.6)

Hypotension: Use with caution in patients with known cardiovascular or cerebrovascular disease (5.7)

Increased Blood Pressure in Children and Adolescents: Monitor blood pressure at the beginning of, and periodically during treatment in children and adolescents (5.8)

Leukopenia, Neutropenia and Agranulocytosis: Monitor complete blood count frequently during the first few months of treatment in patients with a pre-existing low white cell count or a history of leukopenia/neutropenia and discontinue SEROQUEL at the first sign of a decline in WBC in absence of other causative factors (5.9)

Cataracts: Lens changes have been observed in patients during long-term quetiapine treatment. Lens examination is recommended when starting treatment and at 6-month intervals during chronic treatment (5.10)

Concomitant use of strong CYP3A4 inhibitors: Reduce quetiapine dose to one sixth when coadministered with strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) (2.5, 7.1, 12.3)

Concomitant use of strong CYP3A4 inducers: Increase quetiapine dose up to 5 fold when used in combination with a chronic treatment (more than 7-14 days) of potent CYP3A4 inducers (e.g., phenytoin, rifampin, St. John’s wort) (2.6, 7.1, 12.3)

Discontinuation of strong CYP3A4 inducers: Reduce quetiapine dose by 5 fold within 7-14 days of discontinuation of CYP3A4 inducers (2.6, 7.1, 12.3)

Human Experience
In clinical trials, survival has been reported in acute overdoses of up to 30 grams of quetiapine. Most patients who overdosed experienced no adverse reactions or recovered fully from the reported reactions. Death has been reported in a clinical trial following an overdose of 13.6 grams of quetiapine alone. In general, reported signs and symptoms were those resulting from an exaggeration of the drug’s known pharmacological effects, i.e., drowsiness and sedation, tachycardia and hypotension. Patients with pre-existing severe cardiovascular disease may be at an increased risk of the effects of overdose [see Warnings and Precautions (5.11)]. One case, involving an estimated overdose of 9600 mg, was associated with hypokalemia and first degree heart block. In post-marketing experience, there were cases reported of QT prolongation with overdose. There were also very rare reports of overdose of SEROQUEL alone resulting in death or coma.

Management of Overdosage
In case of acute overdosage, establish and maintain an airway and ensure adequate oxygenation and ventilation. Gastric lavage (after intubation, if patient is unconscious) and administration of activated charcoal together with a laxative should be considered. The possibility of obtundation, seizure or dystonic reaction of the head and neck following overdose may create a risk of aspiration with induced emesis. Cardiovascular monitoring should commence immediately and should include continuous electrocardiographic monitoring to detect possible arrhythmias. If antiarrhythmic therapy is administered, disopyramide, procainamide and quinidine carry a theoretical hazard of additive QT-prolonging effects when administered in patients with acute overdosage of SEROQUEL. Similarly it is reasonable to expect that the alpha­ adrenergic-blocking properties of bretylium might be additive to those of quetiapine, resulting in problematic hypotension.

There is no specific antidote to SEROQUEL. Therefore, appropriate supportive measures should be instituted. The possibility of multiple drug involvement should be considered. Hypotension and circulatory collapse should be treated with appropriate measures such as intravenous fluids and/or sympathomimetic agents (epinephrine and dopamine should not be used, since beta stimulation may worsen hypotension in the setting of quetiapine-induced alpha blockade). In cases of severe extrapyramidal symptoms, anticholinergic medication should be administered. Close medical supervision and monitoring should continue until the patient recovers.

Uses

SEROQUEL can be taken with or without food (2.1)

Indication Initial Dose Recommended
Dose
Maximum
Dose
Schizophrenia-Adults (2.2) 25 mg twice daily 150-175 mg/day 750 mg/day
Schizophrenia-Adolescents (13-17 years) (2.2) 25 mg twice daily 400-800 mg/day 800 mg/day
Bipolar Mania-Adults Monotherapy or as an adjust to lithium or divalproex (2.2) 50 mg twice daily 400-800 mg/day 800 mg/day
Bipolar Mania-Children and Adolescents (10-17 years), Monotherapy (2.2) 25 mg twice daily 400-600 mg/day 600 mg/day
Bipolar Depression-Adults (2.2) 50 mg once daily at bedrime 300 mg/day 300 mg/day

Geriatric Use: Consider a lower starting dose (50 mg/day), slower titration and careful monitoring during the initial dosing period in the elderly (2.3, 8.5)

Hepatic Impairment: Lower starting dose (25 mg/day) and slower titration may be needed (2.4, 8.7, 12.3)

Side Effects

Most common adverse reactions (incidence ≥5% and twice placebo):

Adults: somnolence, dry mouth, dizziness, constipation, asthenia, abdominal pain, postural hypotension, pharyngitis, weight gain, lethargy, ALT increased, dyspepsia (6.1)

Children and Adolescents: somnolence, dizziness, fatigue, increased appetite, nausea, vomiting, dry mouth, tachycardia, weight increased (6.1)

Precautions

Cerebrovascular Adverse Reactions: Increased incidence of cerebrovascular adverse events (e.g., stroke, transient ischemic attack) has been seen in elderly patients with dementia-related psychoses treated with atypical antipsychotic drugs (5.3)

Neuroleptic Malignant Syndrome (NMS): Manage with immediate discontinuation and close monitoring (5.4)

Metabolic Changes: Atypical antipsychotics have been associated with metabolic changes. These metabolic changes include hyperglycemia, dyslipidemia, and weight gain (5.5)

  • Hyperglycemia and Diabetes Mellitus: Monitor patients for symptoms of hyperglycemia including polydipsia, polyuria, polyphagia, and weakness. Monitor glucose regularly in patients with diabetes or at risk for diabetes
  • Dyslipidemia: Undesirable alterations have been observed in patients treated with atypical antipsychotics. Appropriate clinical monitoring is recommended, including fasting blood lipid testing at the beginning of, and periodically, during treatment
  • Weight Gain: Gain in body weight has been observed; clinical monitoring of weight is recommended

Tardive Dyskinesia: Discontinue if clinically appropriate (5.6)

Hypotension: Use with caution in patients with known cardiovascular or cerebrovascular disease (5.7)

Increased Blood Pressure in Children and Adolescents: Monitor blood pressure at the beginning of, and periodically during treatment in children and adolescents (5.8)

Leukopenia, Neutropenia and Agranulocytosis: Monitor complete blood count frequently during the first few months of treatment in patients with a pre-existing low white cell count or a history of leukopenia/neutropenia and discontinue SEROQUEL at the first sign of a decline in WBC in absence of other causative factors (5.9)

Cataracts: Lens changes have been observed in patients during long-term quetiapine treatment. Lens examination is recommended when starting treatment and at 6-month intervals during chronic treatment (5.10)

Interactions

Concomitant use of strong CYP3A4 inhibitors: Reduce quetiapine dose to one sixth when coadministered with strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) (2.5, 7.1, 12.3)

Concomitant use of strong CYP3A4 inducers: Increase quetiapine dose up to 5 fold when used in combination with a chronic treatment (more than 7-14 days) of potent CYP3A4 inducers (e.g., phenytoin, rifampin, St. John’s wort) (2.6, 7.1, 12.3)

Discontinuation of strong CYP3A4 inducers: Reduce quetiapine dose by 5 fold within 7-14 days of discontinuation of CYP3A4 inducers (2.6, 7.1, 12.3)

Overdose

Human Experience
In clinical trials, survival has been reported in acute overdoses of up to 30 grams of quetiapine. Most patients who overdosed experienced no adverse reactions or recovered fully from the reported reactions. Death has been reported in a clinical trial following an overdose of 13.6 grams of quetiapine alone. In general, reported signs and symptoms were those resulting from an exaggeration of the drug’s known pharmacological effects, i.e., drowsiness and sedation, tachycardia and hypotension. Patients with pre-existing severe cardiovascular disease may be at an increased risk of the effects of overdose [see Warnings and Precautions (5.11)]. One case, involving an estimated overdose of 9600 mg, was associated with hypokalemia and first degree heart block. In post-marketing experience, there were cases reported of QT prolongation with overdose. There were also very rare reports of overdose of SEROQUEL alone resulting in death or coma.

Management of Overdosage
In case of acute overdosage, establish and maintain an airway and ensure adequate oxygenation and ventilation. Gastric lavage (after intubation, if patient is unconscious) and administration of activated charcoal together with a laxative should be considered. The possibility of obtundation, seizure or dystonic reaction of the head and neck following overdose may create a risk of aspiration with induced emesis. Cardiovascular monitoring should commence immediately and should include continuous electrocardiographic monitoring to detect possible arrhythmias. If antiarrhythmic therapy is administered, disopyramide, procainamide and quinidine carry a theoretical hazard of additive QT-prolonging effects when administered in patients with acute overdosage of SEROQUEL. Similarly it is reasonable to expect that the alpha­ adrenergic-blocking properties of bretylium might be additive to those of quetiapine, resulting in problematic hypotension.

There is no specific antidote to SEROQUEL. Therefore, appropriate supportive measures should be instituted. The possibility of multiple drug involvement should be considered. Hypotension and circulatory collapse should be treated with appropriate measures such as intravenous fluids and/or sympathomimetic agents (epinephrine and dopamine should not be used, since beta stimulation may worsen hypotension in the setting of quetiapine-induced alpha blockade). In cases of severe extrapyramidal symptoms, anticholinergic medication should be administered. Close medical supervision and monitoring should continue until the patient recovers.

Interpreting the GeneSight® Test:
Gene-Drug Interaction Chart

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