Indications

Seroquet ER is indicated for the treatment of:

• Acute and chronic psychoses, including schizophrenia.
• Bipolar disorder, including the treatment of manic, depressive, and mixed episodes, as well as maintenance therapy in combination with a mood stabilizer to prevent recurrence.

Pharmacology

Quetiapine Fumarate is an atypical psychotropic agent that acts as an antagonist at multiple neurotransmitter receptors in the brain, including serotonin (5−HT1​A and 5−HT2​), dopamine (D1​ and D2​), histamine (H1​), and adrenergic (α1​ and α2​) receptors. Its efficacy in schizophrenia is believed to be mediated by its antagonism of D2​ and 5−HT2​ receptors. Antagonism of H1​ receptors may cause somnolence, while antagonism of α1​ receptors may cause orthostatic hypotension.

Dosage & Administration

The dosage and administration schedule vary depending on the indication:

• Acute and chronic psychoses/schizophrenia: Administered twice daily. The daily dose for the first four days is 50 mg (Day 1), 100 mg (Day 2), 200 mg (Day 3), and 300 mg (Day 4). The usual effective dose is 300-450 mg/day, but the range is 150-750 mg/day.
• Manic episodes associated with bipolar disorder: Administered twice daily. The daily dose for the first four days is 100 mg (Day 1), 200 mg (Day 2), 300 mg (Day 3), and 400 mg (Day 4). The dose can be increased up to 800 mg/day by Day 6. The usual effective dose is 400-800 mg/day.
• Depressive episodes associated with bipolar disorder: Administered once daily at bedtime. The usual dose is 300 mg/day. The daily dose for the first four days is 50 mg (Day 1), 100 mg (Day 2), 200 mg (Day 3), and 300 mg (Day 4). The dose can be titrated to 400 mg on Day 5 and up to 600 mg by Day 8.
• Maintenance treatment for bipolar I disorder: The dose should be maintained at the same level that was effective during the acute phase (400-800 mg/day).

Interaction

Caution is advised when using Seroquet ER with drugs that cause electrolyte imbalance or prolong the QT interval. Co-administration with thioridazine, carbamazepine, or phenytoin can increase the clearance of Seroquet ER.

Contraindications

Quetiapine is contraindicated in patients with a known hypersensitivity to it.

Side Effects

The most common side effects include somnolence, dizziness, dry mouth, withdrawal symptoms, elevations in serum triglyceride and cholesterol levels, decreases in HDL cholesterol, weight gain, decreased hemoglobin, and extrapyramidal symptoms.

Pregnancy & Lactation

The safety and efficacy of Quetiapine during human pregnancy have not been established. It should only be used if the benefits outweigh the potential risks. The degree to which it is excreted into human milk is unknown, so women should avoid breastfeeding while taking this medication.

Precautions & Warnings

• Suicide Risk: Depression is associated with an increased risk of suicidal thoughts. This risk persists until remission occurs.
• Cardiovascular Disease: Use with caution in patients with known cardiovascular disease, cerebrovascular disease, or conditions predisposing to hypotension, as Seroquet ER may cause orthostatic hypotension.
• Seizures: Caution is recommended when treating patients with a history of seizures.
• Tardive Dyskinesia: Dose reduction or discontinuation should be considered if signs of tardive dyskinesia appear.
• Neuroleptic Malignant Syndrome: This syndrome has been associated with antipsychotic treatment. Seroquet ER should be discontinued if this occurs.
• QT Prolongation: Caution is advised in patients with cardiovascular disease or a family history of QT prolongation.
• Neutropenia and Hyperglycemia: Severe neutropenia and increases in blood glucose have been reported.

Use in Special Populations

• Elderly: Use with caution. Dose titration may need to be slower and the daily therapeutic dose lower than in younger patients. The mean plasma clearance is reduced by 30-50% in elderly subjects.
• Children and Adolescents: Seroquet ER is not indicated for use in patients under 18 years of age.

Overdose Effects

Overdoses of up to 30 grams have been reported to be survivable. There is no specific antidote. In cases of severe intoxication, intensive care procedures are recommended, including monitoring and support of the cardiovascular system. Refractory hypotension should be treated with intravenous fluids. Sympathomimetic agents like adrenaline and dopamine should be avoided.

Therapeutic Class

Seroquet ER is classified as an atypical neuroleptic drug.

Storage Conditions

Store in a cool and dry place, protected from light. Keep out of the sight and reach of children.