QUETIAPINE FUMARATE
| QUETIAPINE FUMARATE (ke-ti-a'peen) Seroquel, Seroquel XR Classifications: psychotherapeutic agent; antipsychotic, atypical; Therapeutic: atypical antipsychotic Prototype: Clozapine Pregnancy Category: C |
Availability
25 mg, 100 mg, 200 mg tablets; 50 mg, 200 mg, 300 mg, 400 mg extended release tablets
Action
Antagonizes multiple neurotransmitter receptors in the brain including serotonin (5-HT1A and 5-HT2) as well as dopamine D1 and D2 receptors.
Therapeutic Effect
Therapeutic effectiveness indicated by a reduction in psychotic behavior.
Uses
Management of schizophrenia and bipolar disorder.
Unlabeled Uses
Management of agitation and dementia.
Contraindications
Hypersensitivity to quetiapine; pregnancy (category C), lactation; alcohol use; suicidal ideation.
Cautious Use
Dementia-related psychosis; liver function impairment, older adults, cardiovascular disease (history of MI or ischemic heart disease, heart failure, arrhythmias, CVA, hypotension, dehydration, treatment with antihypertensives; history of seizures or suicide; breast cancer; Alzheimer's, Parkinson's disease; concurrent use of centrally acting drugs; patient at risk for aspiration pneumonia; debilitated patients; cerebrovascular disease; adolescents and children with major depression or psychosis.
Route & Dosage
| Bipolar Depression (Immediate Release Only) Adult: PO Day 1: 50 mg at bedtime, Day 2: 100 mg at bedtime, Day 3: 200 mg at bedtime, then 300 mg q.d. at bedtime Schizophrenia Adult: PO (Immediate release) Start 25 mg b.i.d., may increase by 25–50 mg b.i.d. to t.i.d. on the second or third day as tolerated to a target dose of 300–400 mg/d divided b.i.d. to t.i.d., may adjust dose by 25–50 mg b.i.d. q.d. as needed (max: 800 mg/d); (Extended release) 300 mg q.d. at bedtime, titrate up to 400–800 mg q.d. (max: 800 mg/d) Acute Manic Episodes in Bipolar Disorder (Immediate Release Only) Adult: PO Start with total of 100 mg (in two doses) day 1, increase to 400 mg/d (in two doses) by day 4 Geriatric: Titrate more slowly due to risk of orthostatic hypotension Hepatic Impairment Start with 25 mg dose and increase by 25–50 mg/d |
Administration
Oral- Titrate dose over 4 d usually to a target range of 300–400 mg/d. Make further dose adjustments of 25–50 mg 2 times/d at intervals of at least 2 d.
- Retitrate to desired dose when patient has been off the drug for >1 wk.
- Follow recommended lower doses and slower titration for the older adults, the debilitated, and those with hepatic impairment or a predisposition to hypotension.
- Store at 15°–30° C (59°–86° F).
Adverse Effects (≥1%)
Body as a Whole: Asthenia, fever, hypertonia, dysarthria, flu syndrome, weight gain, peripheral edema, increased risk of suicidal thinking. CNS: Dizziness, headache, somnolence. CV: Postural hypotension, tachycardia, palpitations. GI: Dry mouth, dyspepsia, abdominal pain, constipation, anorexia. Metabolic: Hyperglycemia, diabetes mellitus. Respiratory: Rhinitis, pharyngitis, cough, dyspnea. Skin: Rash, sweating. Hematologic: Leukopenia.Interactions
Drug: barbiturates, carbamazepine, phenytoin, rifampin, thioridazine may increase clearance of quetiapine. Quetiapine may potentiate the cognitive and motor effects of alcohol, enhance the effects of antihypertensive agents, antagonize the effects of levodopa and dopamine agonists. Ketoconazole, itraconazole, fluconazole, erythromycin may decrease clearance of quetiapine. Drugs that increase the QT interval (e.g., amiodarone, clarithromycin, antiarrhythmics, haloperidol) increase risk of cardiac effects. Other antipsychotics increase the risk of adverse effects. Herbal: St. John's wort may cause serotonin syndrome (see Appendix F).Pharmacokinetics
Absorption: Rapidly and completely absorbed from GI tract. Peak: 1.5 h. Distribution: 83% protein bound. Metabolism: In liver (CYP3A4). Elimination: 73% in urine, 20% in feces. Half-Life: 6 h.Nursing Implications
Assessment & Drug Effects
- Monitor diabetics for loss of glycemic control.
- Monitor for changes in behavior that may indicate suicidality.
- Reassess need for continued treatment periodically.
- Withhold the drug and immediately report S&S of tardive dyskinesia or neuroleptic malignant syndrome (see Appendix F).
- Lab tests: Periodically monitor liver function, lipid profile, thyroid function, blood glucose, CBC with differential.
- Monitor ECG periodically, especially in those with known cardiovascular disease.
- Perform baseline cataract exam when therapy is started and at 6 mo intervals thereafter.
- Monitor patients with a history of seizures for lowering of the seizure threshold.
Patient & Family Education
- Carefully monitor blood glucose levels if diabetic.
- Exercise caution with potentially dangerous activities requiring alertness, especially during the first week of drug therapy or during dose increments.
- Make position changes slowly, especially when changing from lying or sitting to standing to avoid dizziness, palpitations, and fainting.
- Avoid alcohol consumption and activities that may cause overheating and dehydration.
- Inform physician immediately if you become pregnant.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug