Quetiapine
Tranquilizer, Sedative/Hypnotic · Dibenzothiazepine
Indications
Schizophrenia. Bipolar disorder (acute manic episodes). Adjunctive treatment of major depression.
Dosage
Adults: Schizophrenia: Initially 50 mg daily on 1st day, 100 mg daily on 2nd day, 200 mg daily on 3rd day, 400 mg daily on 4th day. All in two divided doses with or without food. Then titrate according to response, usually 300-450 mg daily. Max 750 mg daily. Elderly: Initially 25 mg once daily increasing gradually in increments of 25-50 mg according to response. Bipolar Disorder: Acute Manic Episodes: Monotherapy or Adjunct Therapy with Lithium or Divalproex: Initial: 100 mg/day given two doses on Day 1. Titrate: Increase to 400 mg/day given in two doses on Day 4 in increments of up to 100 mg/day given in two doses. Adjust doses up to 800 mg/day by Day 6 in increments of not greater than 200 mg/day. Max: 800 mg/day. Adjunctive treatment of major depression: 50 mg once daily at bedtime for 2 days, then 150 mg once daily for 2 days, then adjusted according to response, usual dose 150-300…
Adverse Effects
Somnolence, dizziness, constipation, postural hypotension, dry mouth, liver enzyme abnormalities, blood dyscrasias, hyperprolactinaemia, wt gain, thyroid hormone changes, dyslipidaemia, increased appetite, hyperglycaemia, sleep disturbances, headache, extrapyramidal symptoms, dysarthria, syncope, tachycardia, palpitations, blurred vision, GI upset, asthenia, peripheral oedema, irritability, pyrexia. Neuroleptic malignant syndrome, jaundice, severe neutropenia, tardive dyskinesia; withdraw if occur. Cardiomyopathy, pancreatitis, dysphagia.
Risk Factor (Pregnancy/Lactation)
Pregnancy: Risk cannot be ruled out. Lactation: Contraindicated or not recommended. Precautions: Renal or hepatic impairment, history of cardiovascular or cerebrovascular disease, hypotension, epilepsy, family history of QT prolongation, congenital long QT syndrome, CHF, cardiac hypertrophy, hypokalaemia, hypomagnesaemia, history of seizures, diabetes. Risk factors for stroke, VTE, aspiration pneumonia or sleep apnoea. Risk of GI obstruction. History of urinary retention, prostatic hypertrophy, intestinal obstruction, increased IOP or narrow-angle glaucoma. History of drug or alcohol abuse. Monitor patients for suicidal thoughts or behaviour. Monitor for hyperglycaemia and wt gain. Elderly. Withdraw gradually.
Interactions
CNS depressants, drug prolonging QT intervals or cause electrolyte imbalance, centrally acting drugs, alcohol, CYP3A4 inhibitors (e.g., azole antifungals, macrolides, protease inhibitors), CYP inducers (e.g., carbamazepine, phenytoin), anticholinergics, grapefruit juice.
Advice to Patient
Take with or without meals. To reduce GI upset, take with meals. Do not stop taking medication abruptly, gradually lower the dose and then stop. Contact prescriber if there is difficulty in breathing, increased sleepiness, agitation, dizziness, lack of sleep, change in vision, worsening of condition. Avoid alcohol and caffeine during therapy. Take sufficient amount of fluids (2-3 litres per day) to maintain hydration, unless restricted by the prescriber. Change position slowly from sitting or lying to standing. If you are on a long-term therapy, have regular examinations as directed. On start of therapy or change of dosage, patient should be watched carefully for suicidal tendency by caregiver or family.
Pharmacokinetics
Absorption: Rapidly absorbed following oral administration. Metabolism: Primarily hepatic. Bioavailability: 100% (relative to oral solution). Half-life elimination: Children and Adolescents 12 to 17 Years: Quetiapine: 5.3 hours. Adults: Mean: Terminal: Quetiapine: Approx. 6 hours; Extended release: Approx. 7 hours. Metabolite: N-desalkylquetiapine: 12 hours. Time to peak, plasma: Children and Adolescents 12 to 17 years: Immediate release: 0.5 to 3 hours. Adults: Immediate release: 1.5 hours; Extended release: 6 hours. Excretion: Urine (73% as metabolites, <1% of total dose as unchanged drug); feces (20%).
Unlicensed Use
Children: Schizophrenia: 12-18 yr, initially 25 mg twice daily adjusted in steps of 25-50 mg according to response, max 750 mg daily. Treatment of mania in bipolar disorder: 12-18 yr, 25 mg twice daily on day 1, then 50 mg twice daily on day 2, then 100 mg twice daily on day 3, then 150 mg twice daily on day 4, then 200 mg twice daily on day 5; thereafter dose adjusted according to response in steps no greater than 100 mg daily, usual dose 400-600 mg daily in 2 divided doses.
Brands with this active ingredient
Compiled by Healify Pharmacy from published drug references. How we compile it →
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