Seroquel

Ser·o·quel (sr-kwl)

A trademark for the drug quetiapine fumarate.

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quetiapine fumarate

Seroquel

Pharmacologic class: Dibenzothiazepine derivative

Therapeutic class: Atypical antipsychotic

Pregnancy risk category C

FDA Boxed Warning

• Elderly patients with dementia-related psychosis are at increased risk for death. Over course of 10-week controlled trial, death rate in drug-treated patients was about 4.5%, compared to about 2.6% in placebo group. Although causes of death varied, most appeared to be cardiovascular or infectious. Don't give drug to patients with dementia-related psychosis.
• Drug may increase risk of suicidal thinking and behavior in children and adolescents with major depressive disorder and other psychiatric disorders. Risk must be balanced with clinical need, as depression itself increases suicide risk. With patient of any age, observe closely for clinical worsening, suicidality, and unusual behavior changes when therapy begins. Advise family and caregivers to observe patient closely and communicate with prescriber as needed.
• Drug isn't approved for use in pediatric patients.

Action

Unknown. Antipsychotic effects may occur through antagonism of dopamine D₂ and serotonin 5-HT₂ receptors. Other effects may result partly from antagonism of other receptors, such as histamine H₁ and alpha₁-adrenergic receptors.

Availability

Tablets: 25 mg, 50 mg, 100 mg, 200 mg, 300 mg, 400 mg

⊘ Indications and dosages

➣ Schizophrenia

Adults: Initially, 25 mg P.O. b.i.d., increased by 25 to 50 mg given two to three times daily as tolerated over 3 days, up to 300 to 400 mg/day in two to three divided doses by day 4 (not to exceed 800 mg/day)

➣ Acute manic episodes associated with bipolar I disorder

Adults: 100 mg on day 1, 200 mg on day 2, 300 mg on day 3, 400 mg on day 4, up to 600 mg on day 5, and up to 800 mg on day 6. Maximum daily dosage is 800 mg. May be given as monotherapy or as adjunctive therapy with lithium or divalproex.

➣ Depression associated with bipolar disorder

Adults: Day 1, 50 mg P.O.; day 2, 100 mg P.O. ; day 3, 200 mg P.O.; day 4, 300 mg P.O.

Dosage adjustment

• Hepatic impairment
• History of hypotensive reactions
• Elderly or debilitated patients

Off-label uses

• Bipolar disorder
• Mania
• Obsessive-compulsive disorder
• Posttraumatic stress disorder
• Psychosis related to Parkinson's disease

Contraindications

• Hypersensitivity to drug or its components

Precautions

Use cautiously in:
• hepatic impairment, cardiovascular or cerebrovascular disease, dehydration, hypovolemia, Alzheimer's dementia, hypothyroidism
• history of seizures, suicide attempt, or hypotensive reactions
• elderly or debilitated patients
• pregnant patients
• children (safety not established).

Administration

• Give with or without food.
☞ Don't confuse Seroquel with Serzone (an antidepressant).

Route	Onset	Peak	Duration
P.O.	Rapid	1.5 hr	8-12 hr

Adverse reactions

CNS: dizziness, sedation, cognitive impairment, extrapyramidal symptoms, tardive dyskinesia, neuroleptic malignant syndrome, seizures

CV: palpitations, peripheral edema, orthostatic hypotension

EENT: ear pain, rhinitis, pharyngitis

GI: constipation, dyspepsia, dry mouth, anorexia

Hematologic: leukopenia

Respiratory: cough, dyspnea

Skin: diaphoresis

Other: weight gain, flulike symptoms

Interactions

Drug-drug. Antihistamines, opioids, sedative-hypnotics, other CNS depressants: additive CNS depression

Antihypertensives: increased risk of hypotension

Barbiturates, carbamazepine, corticosteroids, phenytoin, rifampin, thioridazine: increased clearance and decreased efficacy of quetiapine

Dopamine agonists, levodopa: antagonism of these drugs' effects

Erythromycin, fluconazole, itraconazole, ketoconazole, other CYP450-3A4 inhibitors: increased quetiapine effects

Drug-diagnostic tests. Alanine aminotransferase, aspartate aminotransferase: asymptomatic elevations

Total cholesterol, triglycerides: increased levels

Urine tricyclic antidepressant assay: false-positive screen

White blood cells: decreased count

Drug-behaviors. Alcohol use: increased CNS effects

Patient monitoring

☞ Monitor neurologic status, especially for signs and symptoms of tardive dyskinesia or neuroleptic malignant syndrome.
• Monitor blood pressure for orthostatic hypertension.

Patient teaching

• Tell patient he can take with or without food.
☞ Teach patient to recognize and immediately report signs and symptoms of neuroleptic malignant syndrome (such as high fever, sweating, unstable blood pressure, stupor, muscle rigidity, and tardive dyskinesia).
• Instruct patient to move slowly when sitting up or standing, to avoid dizziness from sudden blood pressure decrease.
☞ Tell patient not to stop taking drug abruptly. Tell him dosage must be tapered.
• Caution patient not to drink alcohol.
• Instruct patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.

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Seroquel® Quetiapine, see there