Generic Name: Quetiapine Fumarate
Brand Names: Seroquel
Drug Class: 5HT2 Antagonist, Anti-depressant, Atypical Antipsychotic, Anxiolytic
Similar Class Drugs: Risperidone, Aripiprazole
Available Dosage Forms: Immediate and extended-release oral tablets
What is Quetiapine?
Quetiapine is used to treat a plethora of psychopathological conditions. The primary indication of Quetiapine is in the treatment of major depression, schizophrenia, and bipolar disorder type 1.
It has a broad range of activity as it affects the action of several neurotransmitters. Quetiapine potently antagonizes the 5HT2 serotonin receptor to upregulate the concentration of serotonin in synaptic clefts.1
A marked increase in synaptic serotonin impedes the severity of depressive symptoms. It is also used as an adjunct with Divalproex and lithium to treat manic episodes in bipolar disorder type 1.
Reduction in schizophrenic symptoms by Quetiapine is attributed to its D2 receptor antagonism. The inhibition of dopamine receptors in the mesocortical and mesolimbic pathways prevents the accumulation of dopamine. Depletion in the levels of dopamine then leads to the regression of schizophrenic symptoms.1
Other non-FDA approved uses of Quetiapine include:
– Post-traumatic stress disorder
– Manic episodes in Parkinson’s
– Generalized anxiety disorder
Although it has a number of off-label uses, Quetiapine is not prescribed for long-term treatment due to the lack of evidence supporting its use.1
How to use Quetiapine?
– Dosages of Quetiapine are prescribed based on the condition, severity, and age of patients.
– Adolescents generally receive a higher starting dosage than adults.
– Immediate-release tablets are started with a dosage of 25mg twice daily. The maximum dosage of 750mg has to be given in divided dosages throughout the day.
– Initial dosage of extended-release tablets is 300 mg, given once a day. The maximum dosage of 800mg should be split up and not administered at once.
– The tablets can be taken with or without food.
– Reduction or augmentation of dosages is based on the tolerability and clinical response of patients.
– Caution should be practiced in the elderly, patients with hepatic insufficiency, and patients taking medications that are known for interactions with Quetiapine.
What are the side effects of Quetiapine?
According to a study, hospital admissions after overdose were significantly more for Quetiapine than with Risperidone and Clozapine.2
Common side effects of its use include:
– GI effects: nausea, vomiting, diarrhea, constipation
– CNS effects: sedation, headache, dizziness
Adverse effects noted with Quetiapine:
– Metabolic disturbances: dyslipidemia, hyperglycemia, insulin resistance
– In geriatric population: stroke, cognitive impairment, hip fracture, cardiac adverse events
– Suicidal ideation in children and adolescents
Who should not use Quetiapine?
– Hypersensitive patients
– Dementia-related psychosis
– Patients with prolonged QT interval
Quetiapine must be used with caution in:1
– Pregnant and breastfeeding women
– Diabetes mellitus
– Hypokalemia, hypomagnesemia
– Cardiac arrhythmias
References
- Maan JS, Ershadi M, Khan I, et al. Quetiapine. [Updated 2021 Jul 18]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459145/
- Brett J. Concerns about Quetiapine. Aust Prescr. 2015;38(3):95-97. doi:10.18773/austprescr.2015.032
