Each film-coated tablet contains: Quetiapine Fumarate equivalent to Quetiapine 25 mg/300 mg.
Quetiapine fumarate is a white to off-white crystalline powder which is moderately soluble in water.
Its chemical name is 2-[2-(4-Dibenzo [b,f] [1,4]thiazepin-11-yl-1-piperazinyl) ethoxy]ethanol fumarate. Molecular formula is (C21H25N3O2S)2.C4H4O4 and it has a molecular weight of 883.1.
Pharmacology: Pharmacodynamics: Mechanism of Action: Quetiapine fumarate is a dibenzothiazepine atypical antipsychotic. It is reported to have affinity for serotonin (5-HT2), histaminergic (H1), and adrenergic (α1 and α2) receptors as well as dopamine D2 receptors.
Pharmacokinetics: Quetiapine is well absorbed following oral administration and widely distributed throughout the body. Peak plasma concentrations are reached in about 1.5 hours. It is about 83% bound to plasma proteins. 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, about 73% of a dose appearing in the urine and about 20% in the feces. The elimination half-life has been reported to be about 6 to 7 hours.
Used in the treatment of schizophrenia and of mania associated with bipolar disorder.
Schizophrenia: The usual initial dose is 25 mg twice daily on day one, 50 mg twice daily on day two, 100 mg twice daily on day three, and 150 mg twice daily on day four. The dosage is then adjusted according to response to a usual range of 300 to 450 mg daily given in 2 or 3 divided doses, although 150 mg daily may be adequate for some patients. The maximum recommended dose is 750 mg daily.
Mania: The initial dose is 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. The dose may then be adjusted to a usual range of 400 to 800 mg daily, although, in some patients, 200mg daily may be adequate. Increments in dosage should be no greater than 200 mg daily.
Other: Elderly: Quetiapine should be given in reduced doses to the elderly; a recommended starting dose is 25 mg daily increased in steps of 25 to 50 mg daily according to response. Hepatic and Renal impairment: Reduced doses are also recommended in patients with hepatic or renal impairment. The recommended starting dose is 25 mg daily increased in steps of 25 to 50 mg daily according to response.
Quetiapine should be used with caution in patients with hepatic or renal impairment, with cardiovascular disease or other conditions predisposing to hypotension, or with a history of seizures.
Quetiapine may affect the performance of skilled tasks including driving.
The most frequent adverse effects with quetiapine are somnolence, dizziness, constipation, orthostatic hypotension, dry mouth, and raised liver enzyme values. Quetiapine has been associated with a low incidence of extrapyramidal symptoms. Rises in prolactin concentrations may be less than with chlorpromazine. Weight gain particularly during early treatment has also been noted. Clinical monitoring for hyperglycemia has been recommended, especially in patients with or at risk of developing diabetes. Neuroleptic malignant syndrome is rare with quetiapine but tardive dyskinesia may occur after long-term treatment. Tachycardia and occasionally, syncope have been reported; prolongation of the QT interval is rarely significant. Leucopenia, neutropenia, and eosinophilia have also been reported with quetiapine.
Other adverse effects have included mild asthenia, anxiety, fever, hypertension, myalgia, rhinitis, dyspepsia, rises in plasma- triglyceride and cholesterol concentrations, and reduced plasma thyroid hormone concentrations. There have been rare reports of seizures, hypersensitivity reactions including angioedema, priapism, and peripheral edema. Asymptomatic changes in the lens of the eye have occurred in patients during long-term treatment with quetiapine.
The central effects of other CNS depressants, including alcohol, may be enhanced by Quetiapine. Quetiapine may antagonize the actions of dopaminergics such as levodopa.
CYP3A4 is the 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 inhibitors. 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.
Store at temperatures not exceeding 30°C.
N05AH04 - quetiapine ; Belongs to the class of diazepines, oxazepines and thiazepines antipsychotics.
Qtipine 25: FC tab 25 mg (brownish red colored, round, biconvex, plain on both sides) x 100's. Qtipine 300: FC tab 300 mg (white to off white, capsule shaped, biconvex, with break line on both sides) x 100's.