Quetiapine

What it is and how it works

Mechanism of Action The mechanism of action of quetiapine in the listed indications is unclear. However, the efficacy of quetiapine in these indications could be mediated through a combination of dopamine type 2 (D 2 ) and serotonin type 2A (5HT 2A ) antagonism. The active metabolite, N-desalkyl quetiapine (norquetiapine), has similar activity at D 2 , but greater activity at 5HT 2A receptors, than the parent drug (quetiapine).

Indications

Quetiapine extended-release tablets are an atypical antipsychotic indicated for the treatment of: Schizophrenia Bipolar I disorder, manic or mixed episodes Bipolar disorder, depressive episodes Major depressive disorder, adjunctive therapy with antidepressants Schizophrenia Quetiapine extended-release tablets are indicated for the treatment of schizophrenia. The efficacy of quetiapine extended-release tablets in schizophrenia was established in one 6-week and one maintenance trial in adults with schizophrenia. Efficacy was supported by three 6-week trials in adults with schizophrenia and one 6-week trial in adolescents with schizophrenia (13 to 17 years) treated with SEROQUEL . Bipolar Disorder Quetiapine extended-release tablets are indicated for the acute treatment of manic or mixed episodes associated with bipolar I disorder, both as monotherapy and as an adjunct to lithium or divalproex.

Dosage and administration (summary)

Swallow tablets whole and do not split, chew or crush Take without food or with a light meal (approx. 300 calories) Administer once daily, preferably in the evening Geriatric Use: Consider a lower starting dose (50 mg/day), slower titration, and careful monitoring during the initial dosing period in the elderly. ( 2.3 , 8.5 ) Hepatic Impairment: Lower starting dose (50 mg/day) and slower titration may be needed ( 2.4 , 8.7 , 12.3 ) Indication Initial Dose Recommended Dose Maximum Dose Schizophrenia-Adults 300 mg/day 400 to 800 mg/day 800 mg/day Schizophrenia-Adolescents (13 to 17 years) 50 mg/day 400 to 800 mg/day 800 mg/day Bipolar I Disorder manic or mixed-Acute monotherapy or adjunct to l…

Contraindications

Hypersensitivity to quetiapine or to any excipients in the quetiapine extended-release tablets formulation. Anaphylactic reactions have been reported in patients treated with quetiapine extended-release tablets. Known hypersensitivity to quetiapine extended-release tablets or any components in the formulation.

Warnings and precautions

• Cerebrovascular Adverse Reactions: Increased incidence of cerebrovascular adverse reactions (e.g., stroke, transient ischemic attack) has been seen in elderly patients with dementia-related psychoses treated with atypical antipsychotic drugs • Neuroleptic Malignant Syndrome (NMS): Manage with immediate discontinuation and close monitoring • Metabolic Changes: Atypical antipsychotics have been associated with metabolic changes.

Pregnancy

Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to atypical antipsychotics, including quetiapine extended-release tablets, during pregnancy.

Storage and supply

50 mg Tablets peach, film coated, capsule-shaped, biconvex embossed tablet with “380” on one side and plain on the other are supplied in Bottles of 60 tablets: NDC 51407-799-60 150 mg Tablets white, film coated, capsule-shaped, biconvex embossed tablet with “381” on one side and plain on the other are supplied in Bottles of 60 tablets: NDC 51407-80…

Source: Quetiapine (Quetiapine Extended Release) — US FDA prescribing information, 2025-11-21, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.