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Indications/Uses
Quetiapine is used in the treatment of schizophrenia and of mania associated with bipolar disorder.
Dosage/Direction for Use
SCHIZOPHRENIA: 50 mg on day one. 100 mg is given on day two, 200 mg on day three, and 300 mg on day four; daily doses are given in 2 divided doses.
Usual Range: 300 to 450 mg daily, although 150 mg daily may be adequate for some patients.
THE MAXIMUM RECOMMENDED DOSE: 50 mg daily. The usual initial daily dose is increased in days two and three in increment of 50 to 150 mg, as tolerated, to a target of 300 to 400 mg daily by day four. The daily dose on the first day is given in 2 divided doses, but may be given in 3 divided doses thereafter. The daily dosage may be further adjusted as necessary in increment or decrement of 50 to 100 mg at intervals of not less than 2 days to a usual range.
ACUTE MANIC EPISODES: Associated bipolar disorder 50 mg twice daily on day one, 100 mg twice daily on day two, 150 mg twice daily on day three and 200 mg twice daily on day four.
Usual Range: 400 to 800 mg daily, although, in some patients, 200 mg may be adequate. Increments in dosage should be no greater than 200 mg daily. Quetiapine should be given in reduced doses for elderly, a recommended starting dose is 25 mg daily which may be increased everyday in increments of 25 mg to 50 mg according to response.
Or as prescribed by the physician.
Usual Range: 300 to 450 mg daily, although 150 mg daily may be adequate for some patients.
THE MAXIMUM RECOMMENDED DOSE: 50 mg daily. The usual initial daily dose is increased in days two and three in increment of 50 to 150 mg, as tolerated, to a target of 300 to 400 mg daily by day four. The daily dose on the first day is given in 2 divided doses, but may be given in 3 divided doses thereafter. The daily dosage may be further adjusted as necessary in increment or decrement of 50 to 100 mg at intervals of not less than 2 days to a usual range.
ACUTE MANIC EPISODES: Associated bipolar disorder 50 mg twice daily on day one, 100 mg twice daily on day two, 150 mg twice daily on day three and 200 mg twice daily on day four.
Usual Range: 400 to 800 mg daily, although, in some patients, 200 mg may be adequate. Increments in dosage should be no greater than 200 mg daily. Quetiapine should be given in reduced doses for elderly, a recommended starting dose is 25 mg daily which may be increased everyday in increments of 25 mg to 50 mg according to response.
Or as prescribed by the physician.
Overdosage
Symptoms: In general, reported signs and symptoms were those resulting from an exaggeration of the active substance's known pharmacological effects, i.e., drowsiness and sedation, tachycardia and hypotension. Overdose could lead to QT-prolongation, seizures, status epilepticus, rhabdomyolysis, respiratory depression, urinary retention, confusion, delirium and/or agitation, coma and death. Patients with pre-existing severe cardiovascular disease may be at an increased risk of the effects of overdose.
Management of overdose: There is no specific antidote to Quetiapine. Whilst the prevention of absorption in overdose has not been investigated, gastric lavage can be indicated in severe poisoning and should be perform within one hour of ingestion. The administration of activated charcoal should be considered.
Management of overdose: There is no specific antidote to Quetiapine. Whilst the prevention of absorption in overdose has not been investigated, gastric lavage can be indicated in severe poisoning and should be perform within one hour of ingestion. The administration of activated charcoal should be considered.
Administration
May be taken with or without food.
Contraindications
Hypersensitivity to active ingredient or any of the constituent.
Special Precautions
Quetiapine should be used with caution in patients with hepatic or renal impairment, with cardiovascular disease or other conditions predisposing to hypotension, with cerebrovascular disease, or with a history of seizures or conditions that lower the seizure threshold.
Quetiapine may affect the performance of skilled tasks including driving.
Gradual withdrawal of Quetiapine is recommended because of the risk of withdrawal symptoms, including nausea, vomiting, insomnia, and rebound psychoses, with abrupt cessation. Reduced doses are also recommended in patients with hepatic or renal impairment.
Quetiapine may affect the performance of skilled tasks including driving.
Gradual withdrawal of Quetiapine is recommended because of the risk of withdrawal symptoms, including nausea, vomiting, insomnia, and rebound psychoses, with abrupt cessation. Reduced doses are also recommended in patients with hepatic or renal impairment.
Use In Pregnancy & Lactation
Pregnancy: Quetiapine should only be used during pregnancy if the benefits justify the potential risks.
Lactation: Women who are breastfeeding should therefore be advised to avoid breastfeeding while taking quetiapine.
Lactation: Women who are breastfeeding should therefore be advised to avoid breastfeeding while taking quetiapine.
Adverse Reactions
The most frequent adverse effects with quetiapine are somnolence and dizziness. Mild asthenia, anxiety, fever, rhinitis, peripheral edema, constipation, dyspepsia, dry mouth, and raised liver enzyme values are also relatively common. Orthostatic hypotension associated with dizziness, tachycardia, and syncope has been reported, particularly during initial dose-titration. Prolongation of QT interval is rarely significant with quetiapine. Hyperglycemia and exacerbation of pre-existing diabetes have been reported rarely. Clinical monitoring for hyperglycemia has been recommended, especially in patients with, or at risk of developing, diabetes.
Weight gain, particularly during early treatment, eosinophilia have also been reported. Other adverse effects have included rises in plasma-triglyceride and cholesterol concentrations. There have been rare reports of seizures, hypersensitivity reactions including angioedema, and priapism.
Weight gain, particularly during early treatment, eosinophilia have also been reported. Other adverse effects have included rises in plasma-triglyceride and cholesterol concentrations. There have been rare reports of seizures, hypersensitivity reactions including angioedema, and priapism.
Drug Interactions
The central effects of other CNS depressants including alcohol may be enhanced by quetiapine. Quetiapine should be used with caution in patients receiving antihypertensive or drug that prolongs the QT intervals.
Quetiapine may antagonize the action of dopaminergic such as levodopa.
CYP3A4 is main isoenzyme responsible for cytochrome P450-mediated metabolism of quetiapine and caution is advised when quetiapine is used with potent inhibitors of CYP3A4 such as erythromycin, fluconazole, itraconazole, and ketoconazole; lower doses of quetiapine should be used when given with such drugs. Conversely, enzyme inducers such as carbamazepine and phenytoin may decrease the plasma concentrations of quetiapine, and higher doses of quetiapine, may be, necessary. Thioridazine has also been reported to increase the clearance of quetiapine.
Quetiapine may antagonize the action of dopaminergic such as levodopa.
CYP3A4 is main isoenzyme responsible for cytochrome P450-mediated metabolism of quetiapine and caution is advised when quetiapine is used with potent inhibitors of CYP3A4 such as erythromycin, fluconazole, itraconazole, and ketoconazole; lower doses of quetiapine should be used when given with such drugs. Conversely, enzyme inducers such as carbamazepine and phenytoin may decrease the plasma concentrations of quetiapine, and higher doses of quetiapine, may be, necessary. Thioridazine has also been reported to increase the clearance of quetiapine.
Storage
Store at temperature not exceeding 30°C.
Action
Pharmacotherapeutic group: Antipsychotics.
Pharmacology: Pharmacodynamics: Mechanism of Action: Quetiapine is an atypical antipsychotic agent. Quetiapine and the active human plasma metabolite, norquetiapine interact with a broad range of neurotransmitter receptors. Quetiapine and norquetiapine exhibit affinity for brain serotonin (5HT2) and dopamine D1- and D2- receptors. It is this combination of receptor antagonism with a higher selectivity for 5HT2 relative to D2- receptors, which is believed to contribute to the clinical antipsychotic properties and low extrapyramidal side effect (EPS) liability of quetiapine compared to typical antipsychotics. Quetiapine and norquetiapine have no appreciable affinity at benzodiazepine receptors but high affinity at histaminergic and adrenergic alpha-1 receptors and moderate affinity at adrenergic alpha-2 receptors. Quetiapine also has low or no affinity for muscarinic receptors, while norquetiapine has moderate to high affinity at several muscarinic receptors, which may explain anticholinergic (muscarinic) effects. Inhibition of norepinephrine transporter (NET) and partial agonist action at 5-HT1A sites by norquetiapine may contribute to quetiapine's therapeutic efficacy as an antidepressant.
Pharmacodynamic effects: Quetiapine is active in tests for antipsychotic activity, such as conditioned avoidance. It also blocks the action of dopamine agonists, measured either behaviorally or electrophysiologically, and elevates dopamine metabolite concentrations, a neurochemical index of D2-receptor blockade. In pre-clinical tests predictive of EPS, quetiapine is unlike typical antipsychotics and has an atypical profile. Quetiapine does not produce dopamine D2-receptor supersensitivity after chronic administration. Quetiapine produces only weak catalepsy at effective dopamine D2-receptor blocking doses. Quetiapine demonstrates selectivity for the limbic system by producing depolarization blockade of the mesolimbic but not the nigrostriatal dopamine-containing neurons following chronic administration. Quetiapine exhibits minimal dystonic liability in haloperidol-sensitized or drug-naive Cebus monkeys after acute and chronic administration.
Pharmacokinetics: Quetiapine is well absorbed after oral doses and widely distributed throughout the body. Peak plasma concentration is reached in about 1.5 hours. It is about 83% bound to plasma protein. Quetiapine is extensively metabolized in the liver by sulfoxidation mediated mainly by the cytochrome P450 isoenzyme CYP3A4 and by oxidation. It is excreted mainly as inactive metabolites with about 73% of a dose appearing in the urine and about 20% in feces. The elimination half-life has been reported to be about 6 to 7 hours. It is distributed into breast milk.
Pharmacology: Pharmacodynamics: Mechanism of Action: Quetiapine is an atypical antipsychotic agent. Quetiapine and the active human plasma metabolite, norquetiapine interact with a broad range of neurotransmitter receptors. Quetiapine and norquetiapine exhibit affinity for brain serotonin (5HT2) and dopamine D1- and D2- receptors. It is this combination of receptor antagonism with a higher selectivity for 5HT2 relative to D2- receptors, which is believed to contribute to the clinical antipsychotic properties and low extrapyramidal side effect (EPS) liability of quetiapine compared to typical antipsychotics. Quetiapine and norquetiapine have no appreciable affinity at benzodiazepine receptors but high affinity at histaminergic and adrenergic alpha-1 receptors and moderate affinity at adrenergic alpha-2 receptors. Quetiapine also has low or no affinity for muscarinic receptors, while norquetiapine has moderate to high affinity at several muscarinic receptors, which may explain anticholinergic (muscarinic) effects. Inhibition of norepinephrine transporter (NET) and partial agonist action at 5-HT1A sites by norquetiapine may contribute to quetiapine's therapeutic efficacy as an antidepressant.
Pharmacodynamic effects: Quetiapine is active in tests for antipsychotic activity, such as conditioned avoidance. It also blocks the action of dopamine agonists, measured either behaviorally or electrophysiologically, and elevates dopamine metabolite concentrations, a neurochemical index of D2-receptor blockade. In pre-clinical tests predictive of EPS, quetiapine is unlike typical antipsychotics and has an atypical profile. Quetiapine does not produce dopamine D2-receptor supersensitivity after chronic administration. Quetiapine produces only weak catalepsy at effective dopamine D2-receptor blocking doses. Quetiapine demonstrates selectivity for the limbic system by producing depolarization blockade of the mesolimbic but not the nigrostriatal dopamine-containing neurons following chronic administration. Quetiapine exhibits minimal dystonic liability in haloperidol-sensitized or drug-naive Cebus monkeys after acute and chronic administration.
Pharmacokinetics: Quetiapine is well absorbed after oral doses and widely distributed throughout the body. Peak plasma concentration is reached in about 1.5 hours. It is about 83% bound to plasma protein. Quetiapine is extensively metabolized in the liver by sulfoxidation mediated mainly by the cytochrome P450 isoenzyme CYP3A4 and by oxidation. It is excreted mainly as inactive metabolites with about 73% of a dose appearing in the urine and about 20% in feces. The elimination half-life has been reported to be about 6 to 7 hours. It is distributed into breast milk.
MedsGo Class
Antipsychotics
Features
Dosage
25 mg
Ingredients
- Quetiapine
Packaging
Film-Coated Tablet 1's
Generic Name
Quetiapine Fumarate
Registration Number
DRP-4183-01
Classification
Prescription Drug (RX)
Reviews
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Product Questions
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