The trade name is Seroquel, the generic bioequivalent analog is Quetiapine fumarate. The medication belongs to the group of atypical antipsychotic drugs and is prescribed to manage chronic and acute schizophrenia with positive or negative symptoms, maniacal-depressive psychosis, major depressive disorder (in conjunction with antidepressants), maniac episodes, and other types of psychosis. The product has an antipsychotic effect.
Mode of action
Seroquel primarily interacts with histamine receptors, serotonin 5-HT2 receptors, and D1- and D2-dopamine receptors in the brain. Clinical studies proved that the drug is effective when taken twice a day. This is confirmed by the fact that the effect of quetiapine on 5-HT2- and D2-receptors may last up to 12 hours.
Seroquel and its generic analogs can only be used in patients who have been diagnosed with:
- hebephrenic type schizophrenia;
- schizo-affective psychosis;
- manic and depressive episodes typical for bipolar disorder;
- MDD (major depressive disorder);
- organic psychotic conditions.
Quetiapine fumarate is contraindicated for patients with:
- hypersensitivity to the medication or its components;
- Severely impaired liver or kidney function;
- cardiac arrhythmia, heart failure or stroke;
- suicidal ideation or attempts;
- high blood sugar;
- alcohol abuse;
- obesity, diabetes;
- dementia-related psychosis;
- epileptiform seizures;
- low blood levels of magnesium or potassium;
- pregnancy and lactation.
Severe drug-to-drug interactions are potent when Seroquel is concomitantly used with:
- azole antifungal agents;
- antiarrhythmic remedies;
- erythromycin and other CYP3A4 inhibitors;
- HIV integrase inhibitors;
- other antipsychotic drugs;
- grapefruit juice.
Administration and dosing
The medication is dispensed in the form of prolonged release and immediate release tablets of the following strengths: 25, 50, 100, 150, 200, 300, and 400 mg. The ultimate dose is determined individually by a doctor only based on a patient’s age, condition, and severity of a disease.
The standard adult dose for:
- Schizophrenia: 150 mg of Seroquel taken in 2 – 3 divided parts. The maximum dose is 750 mg per day.
- Bipolar disorder: 400 mg of Seroquel or Quetiapine fumarate taken in divided doses. The maximum daily amount of the drug is 800 mg per day.
- Depression: the daily dose of Seroquel must not be higher than 300 mg.
For pediatric and geriatric individuals, the dosing is selected individually by the medical professional. The dosage may be increased/ decreased according to the tolerability and clinical response. Seroquel is not indicated for patients under 10.
The therapy with Quetiapine fumarate may last up to 6 – 8 weeks. The discontinuation requires gradual dose lowering. The abrupt stop of Seroquel has a risk of withdrawal syndrome.
Dose adjustments are recommended under moderate to severe liver conditions.
Food consumption does not influence the absorption of Seroquel.
Orthostatic hypotension, high arterial blood pressure, tachycardia, leucopenia, heart failure (in elderly subjects with dementia).
Nervous system and sense organs
Drowsiness, vertigo, psychic tension, neuroleptic malignant syndrome, shivering, speech impairment, motor dysfunction.
Cholesterol level elevation, changes in the liver enzyme levels, hyperglycosemia, dyslipidemia.
Dry mouth, thirst, diarrhea, constipation, dyspepsia.
Painful condition including abdominal pain, headache, backache, muscle cramps, earache, chest pain, asthenic syndrome, rhinitis, urinary tract infections, febrilily, weight gain, anaphylactic reactions.