Trade name Seroquel
Pregnancy category C
Administration oral agent.
Bioavailability 100%.
Protein binding 83%.
Metabolism Hepatic via CYP3A4-catalysed sulfoxidation to its active metabolite norquetiapine (N-desalkylquetiapine)
Biological half-life 7 hours, parent compound, and 9–12 hours for active metabolite,
Excretion by renal mechanisms 73%, by feces 20%.
An atypical antipsychotic approved for the treatment of schizophrenia, bipolar disorder, and along with an antidepressant to treat major depressive disorder.
Sometimes used as a sleep aid because of its sedating effect but this use is not recommended.
Seroquel XR 150 mg tablet.
Has discontinuation rates similar to those of typical antipsychotics.
Associated with suicide attempt, suicide, death, QTc prolongation, low blood pressure, tachycardia, sedation, gynecomastia, galactorrhea, menstrual irregularity and white blood cell count changes at a rate similar to first generation antipsychotics.
There is tentative evidence of the benefit of quetiapine versus placebo in schizophrenia, due to high rate of attrition in trials of greater than 50%, and the lack of data on economic outcomes, social functioning, or quality of life.
It is debatable whether, as a class, typical or atypical antipsychotics are more effective.
Has lower rates of extrapyramidal side effects, there is greater sleepiness and rates of dry mouth.
May be less efficacious than olanzapine and risperidone; produce fewer movement related side effects than paliperidone, aripiprazole, ziprasidone, risperidone and olanzapine; and produce weight gain similar to risperidone, clozapine and aripiprazole.
Used to treat depressive episodes, acute manic episodes associated with bipolar I disorder, as either monotherapy or adjunct therapy to lithium, valproate or lamotrigine, and maintenance treatment of bipolar I disorder, as adjunct therapy to lithium or divalproex.
Effective when used by itself and when used along with other medications in major depressive disorder.
Sedation is often an undesirable side effect.
Does not decrease agitation among people with Alzheimer’s, worsens intellectual functioning in the elderly with dementia and therefore is not recommended
Use of low doses of quetiapine for insomnia is not recommended as there is little evidence of benefit and concerns regarding adverse effects.
Sometimes used as an augmentation agent, to treat conditions such as Tourette syndrome, musical hallucinations and anxiety disorders.
Among the most widely used medications for the treatment of Parkinson’s disease psychosis due to their very low extrapyramidal side effects.
Very common adverse effects include:
Dry mouth
Dizziness
Headache
Somnolence causes the 5th most sedation of antipsychotics.
Extended release formulations tend to produce less sedation.
Common adverse effects include:
Hypertension
Orthostatic hypotension
High pulse rate
High blood cholesterol
Elevated serum triglycerides
Abdominal pain
Constipation
Increased appetite
Vomiting
Increased liver enzymes
Backache
Asthenia
Insomnia
Lethargy
Tremor
Agitation
Nasal congestion
Pharyngitis
Fatigue
Pain
Dyspepsia
Peripheral edema
Dysphagia
Rare adverse effects include:
Prolonged QT interval
Sudden cardiac death.
Syncope
Diabetic ketoacidosis
Restless legs syndrome
Hyponatraemia
Jaundice
Pancreatitis
Agranulocytosis
Leukopenia
Neutropenia
Eosinophilia
Anaphylaxis
Seizure
Hypothyroidism
Myocarditis
Cardiomyopathy
Hepatitis
Suicidal ideation
Priapism
Stevens-Johnson syndrome
Neuroleptic malignant syndrome.
Tardive Dyskinesia
This agent minimizes symptoms of tardive dyskinesia caused by other atypicals.
Causes more weight gain than fluphenazine, haloperidol, loxapine, molindone, olanzapine, pimozide, risperidone, thioridazine, thiothixene, trifluoperazine, and ziprasidone, but less than chlorpromazine, clozapine, perphenazine, and sertindole.
May lower the seizure threshold in some patients.
Should be taken with caution in combination with drugs such as bupropion.
Use should be discontinued gradually to avoid withdrawal symptoms or relapse.
Because of compensatory changes at dopamine, serotonin, adrenergic and histamine receptor sites in the central nervous system, withdrawal symptoms can occur during abrupt reduction in dosage.
Withdrawal symptoms after discontinuation : include nausea, emesis, lightheadedness, diaphoresis, dyskinesia, orthostatic hypotension, tachycardia, insomnia, nervousness, dizziness, headache, excessive crying, and anxiety.
Most instances of acute overdosage result only in sedation.
Hypotension and tachycardia, cardiac arrhythmia, coma and death have occurred in adults with overdosage.
Serum concentrations are usually in the 1–10 mg/L range in overdose survivors, while postmortem blood levels of 10–25 mg/L are generally observed in fatal cases.
Placental exposure is least for quetiapine compared to other atypical antipsychotics, and data suggests it is unlikely to result in any major fetal malformations.
It is secreted in breast milk.
A dopamine, serotonin, and adrenergic antagonist, and a potent antihistamine with clinically negligible anticholinergic properties.
At very low doses it acts primarily as an histamine receptor antihistamine and α1-adrenergic blocker.
At moderate doses it activates the adrenergic system and binds strongly to serotonin receptors and autoreceptors.
At high doses, it starts blocking significant amounts of dopamine receptors.
As a result of compensatory changes at dopamine, serotonin, adrenergic and histamine receptor sites in the central nervous system, a gradual reduction in dosage is recommended to minimize or avoid withdrawal symptoms.
Withdrawal symptoms include trouble sleeping, nausea, vomiting, lightheadedness, sweating, feeling light headed when standing, fast heart rate, as well as nervousness, dizziness, headache, and anxiety.