Q

quetiapine

kwet-eye-a-peen

(Apo-Quetiapine , Seroquel, Seroquel XR)

BLACK BOX ALERT Increased risk of suicidal ideation and behavior in children, adolescents, young adults 18–24 yrs with major depressive disorder, other psychiatric disorders. Elderly with dementia-related psychosis are at increased risk for death.

Do not confuse quetiapine with olanzapine, or Seroquel with Sinequan.

classification

PHARMACOTHERAPEUTIC: Dibenzapine derivative. CLINICAL: Antipsychotic (see p. 67C).

Action

Antagonizes dopamine, serotonin, histamine, alpha₁-adrenergic receptors. Therapeutic Effect: Diminishes psychotic disorders. Produces moderate sedation, few extrapyramidal effects. No anticholinergic effects.

Pharmacokinetics

Rapidly, well absorbed after PO administration. Protein binding: 83%. Widely distributed in tissues; CNS concentration exceeds plasma concentration. Metabolized in liver. Primarily excreted in urine. Half-life: 6 hrs.

Uses

Treatment of schizophrenia. Treatment of acute manic episodes with bipolar disorder (alone or in combination with lithium or valproate). Maintenance treatment of bipolar disorder. Treatment of acute depressive episodes associated with bipolar disorder. Adjunctive treatment in major depressive disorder (MDD). OFF-LABEL: Autism, delirium in critically ill pts, psychosis/agitation related to Alzheimer’s dementia.

Precautions

Contraindications: None known. Cautions: Renal impairment, preexisting abnormal lipid profile, those at risk for aspiration pneumonia, cardiovascular disease (e.g., HF, history of MI), cerebrovascular disease, hepatic impairment, dehydration, hypovolemia, history of drug abuse/dependence, seizures, hypothyroidism, pts at risk for suicide, Parkinson’s disease, decreased GI motility, urinary retention, narrow-angle glaucoma, diabetes, visual problems.

 ​Lifespan considerations

Pregnancy/Lactation: Unknown if drug is distributed in breast milk. Not recommended for breast-feeding mothers. Pregnancy Category C. Children: Safety and efficacy not established. Elderly: No age-related precautions noted, but lower initial and target dosages may be necessary.

Interactions

DRUG: Medications prolonging QT interval (e.g., amiodarone) may increase risk of QT prolongation. Alcohol, other CNS depressants may increase CNS depression. May increase hypotensive effects of antihypertensives. Hepatic enzyme inducers (e.g., phenytoin) may increase clearance. CYP3A4 inhibitors (e.g., clarithromycin, erythromycin, fluconazole, itraconazole) may increase effects. HERBAL: St. John’s wort may decrease concentration. Gotu kola, kava kava, St. John’s wort, valerian may increase CNS depression. FOOD: None known. LAB VALUES: May decrease total free thyroxine (T₄) serum levels. May increase serum cholesterol, triglycerides, AST, ALT, WBC, GGT. May produce false-positive pregnancy test result.

Availability (Rx)

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

Tablets, Extended-Release: 50 mg, 150 mg, 200 mg, 300 mg, 400 mg.

Administration/handling

PO

• Give immediate-release tablets without regard to food. • Do not break, crush, dissolve, or divide extended-release tablets. • Extended-release tablets should be given without regard to food or with a light meal in evening.

Indications/routes/dosage

Note: When restarting pts who have been off quetiapine for less than 1 wk, titration is not required and maintenance dose can be reinstituted. • When restarting pts who have been off quetiapine for longer than 1 wk, follow initial titration schedule.

Psychotic disorders, schizophrenia

PO: ADULTS, ELDERLY: Initially, 25 mg twice a day, then 25–50 mg 2–3 times a day on the second and third days, up to 300–400 mg/day in divided doses 2–3 times a day by the fourth day. Further adjustments of 25–50 mg twice a day may be made at intervals of 2 days or longer. Maintenance: 300–800 mg/day (adults); 50–200 mg/day (elderly). CHILDREN 13 YRS AND OLDER: Initially, 25 mg twice daily on day 1, 50 mg twice daily on day 2, then increase by 100 mg/day to target dose of 400 mg/day on day 5. Seroquel XR: Initially, 300 mg/day in evening. May increase at intervals as short as 1 day up to 300 mg/day. Range: 400–800 mg/day.

Mania in bipolar disorder

PO: ADULTS, ELDERLY: Initially, 50 mg twice a day for 1 day. May increase in increments of 100 mg/day to 200 mg twice a day on day 4. May increase in increments of 200 mg/day to 800 mg/day on day 6. Range: 400–800 mg/day. CHILDREN 10 YRS AND OLDER: 25 mg twice daily on day 1, 50 mg twice daily on day 2, then increase by 100 mg/day until target dose of 400 mg/day reached on day 5. May increase up to 600 mg/day. Range: 400–600 mg/day. Seroquel XR: Initially, 300 mg on day 1 in the evening; 600 mg on day 2 and adjust between 400–800 mg/day thereafter.

Depression in bipolar disorder

PO: ADULTS, ELDERLY: Initially, 50 mg/day on day 1, increase to 100 mg/day on day 2, then increase by 100 mg/day up to target dose of 300 mg/day. Seroquel XR: Initially, 50 mg on day 1 in the evening, 100 mg on day 2, 200 mg on day 3, 300 mg on day 4 and thereafter.

Adjunctive therapy in MDD

PO: ADULTS, ELDERLY: (SEROQUEL XR): Initially, 50 mg on days 1 and 2; then 150 mg on days 3 and 4; then 150–300 mg/day thereafter.

Dosage in hepatic impairment

Immediate-Release: Initially, 25 mg/day. Increase by 25–50 mg/day to effective dose.

Extended-Release: Initially, 50 mg/day, increase by 50 mg/day until effective dose.

Side effects

Frequent (19%–10%): Headache, drowsiness, dizziness. Occasional (9%–3%): Constipation, orthostatic hypotension, tachycardia, dry mouth, dyspepsia (heartburn, indigestion, epigastric pain), rash, asthenia (loss of strength, energy), abdominal pain, rhinitis. Rare (2%): Back pain, fever, weight gain.

Adverse effects/toxic reactions

Overdose may produce heart block, hypotension, hypokalemia, tachycardia.

Nursing considerations

Baseline assessment

Assess behavior, appearance, emotional status, response to environment, speech pattern, thought content. Obtain baseline CBC, hepatic enzyme levels before initiating treatment and periodically thereafter.

Intervention/evaluation

Monitor mental status, onset of extrapyramidal symptoms. Assist with ambulation if dizziness occurs. Supervise suicidal-risk pt closely during early therapy (as psychosis, depression lessens, energy level improves, increasing suicide potential). Monitor B/P for hypotension, lipid profile, blood glucose, CBC, or worsening depression, unusual behavior. Assess pulse for tachycardia (esp. with rapid increase in dosage). Assess bowel activity for evidence of constipation. Assess for therapeutic response (improved thought content, increased ability to concentrate, improvement in self-care). Eye exam to detect cataract formation should be obtained q6mos during treatment.

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