Quetiapine (Seroquel): Uses, Dosage, Side Effects, and What to Expect
Quetiapine (brand name Seroquel) is an atypical antipsychotic FDA-approved for bipolar disorder, including both mania and bipolar depression, as well as schizophrenia and, in its extended-release form, as an add-on for depression. It’s one of the few medications approved for both poles of bipolar illness. It’s strongly sedating, which is why it’s taken in the evening and why it’s sometimes used off-label for sleep. The trade-offs are weight gain and effects on blood sugar and cholesterol, so regular monitoring is part of treatment.
Atypical (second-generation) antipsychotic
300 mg in the evening
Sedation and metabolic effects
No. Can be prescribed by telehealth
What Is Quetiapine Used For?
FDA-approved uses
- Bipolar I disorder, acute mania or mixed episodes, alone or with lithium or divalproex
- Bipolar depression (bipolar disorder treatment)
- Bipolar I maintenance, as an add-on to lithium or divalproex
- Add-on treatment for major depressive disorder (Seroquel XR) when an antidepressant alone isn’t enough (depression treatment)
- Schizophrenia
Common off-label uses
- Sleep, at low doses. See the section on sleep below.
- Anxiety or agitation in selected cases
How Does Quetiapine Work?
Quetiapine blocks dopamine and serotonin (5-HT2A) receptors, which helps calm mania and psychosis. Its main breakdown product also blocks norepinephrine reuptake, which is thought to contribute to its antidepressant effect. Strong histamine blocking causes the sedation, and alpha-1 blocking can cause dizziness when standing.
Quetiapine Dosage
| Use (Seroquel XR, adults) | How it’s started | Usual dose | Maximum |
|---|---|---|---|
| Bipolar depression | 50 mg day 1, up to 300 mg by day 4 | 300 mg | 300 mg |
| Add-on for depression | 50 mg days 1–2, 150 mg day 3 | 150–300 mg | 300 mg |
| Bipolar mania | 300 mg day 1, 600 mg day 2 | 400–800 mg | 800 mg |
| Schizophrenia | 300 mg | 400–800 mg | 800 mg |
Source: Seroquel XR FDA prescribing information. Older adults and people with liver impairment start at 50 mg and increase more slowly. Immediate-release Seroquel is usually taken in divided doses.
- Take Seroquel XR once daily in the evening, without food or with a light meal. Swallow it whole.
- Stand up slowly, especially in the first days, because dizziness and fainting are most likely during dose increases.
How Long Does Quetiapine Take to Work?
Sedation and calmer sleep start the first night. For mania, improvement often begins within the first week. For bipolar depression and as an add-on for depression, mood improvement is often noticeable within 1 to 2 weeks and continues over several weeks.
Quetiapine Side Effects
Sedation
Drowsiness is the most common side effect. In Seroquel XR trials it affected 52% of people with bipolar depression (versus 13% on placebo) and 40% in depression add-on trials (versus 9%). It often eases over the first weeks, but morning grogginess can persist for some people.
Weight, blood sugar, and cholesterol
| Measure (Seroquel XR trials) | Quetiapine | Placebo |
|---|---|---|
| Gained 7%+ body weight (bipolar depression) | 8% | 1% |
| Gained 7%+ body weight (depression add-on) | 5% | 2% |
| High total cholesterol (depression trials) | 13–16% | 7% |
| High triglycerides (depression trials) | 16–17% | 8% |
Source: Seroquel XR FDA prescribing information.
Fasting blood sugar can also rise, and diabetes can develop in some people. That’s why weight, blood sugar (or A1c), and cholesterol are checked before starting and periodically during treatment.
Other common side effects
Dry mouth, constipation, dizziness, increased appetite, indigestion, fatigue, and stuffy nose.
Serious but less common risks
- Dizziness or fainting on standing, most likely during dose increases
- Tardive dyskinesia, involuntary movements that can become permanent; risk rises with dose and duration
- Neuroleptic malignant syndrome, a rare emergency with fever, stiffness, and confusion
- Cataracts. The label recommends an eye exam at the start and every 6 months with long-term use.
- Heart rhythm changes in overdose or with other risk factors
- Low white blood cell counts and thyroid changes, rarely
Quetiapine for Sleep
Low-dose quetiapine is widely prescribed off-label for insomnia because it’s so sedating. It isn’t FDA-approved for sleep, and its weight, blood sugar, and cholesterol effects can occur even at lower doses. For insomnia alone, we generally start with CBT-I strategies and options with fewer metabolic risks, such as trazodone or low-dose doxepin. Quetiapine makes more sense when sleep problems come with bipolar disorder or another condition it treats. Learn about our insomnia treatment.
Who Should Be Careful With Quetiapine
- Diabetes, prediabetes, high cholesterol, or obesity
- Heart disease, low blood pressure, or QT prolongation
- Older adults, especially those with dementia
- Seizure disorders, liver disease, or a history of low white blood cell counts
- Pregnancy or breastfeeding
Interactions
Strong CYP3A4 inhibitors, such as ketoconazole and some HIV medicines, can raise quetiapine levels sharply; the label calls for cutting the dose to one-sixth. Strong inducers, such as carbamazepine, phenytoin, rifampin, and St. John’s wort, can lower levels a lot. Other QT-prolonging drugs and other sedatives also need caution. Avoid alcohol.
Stopping: taper with your prescriber. Stopping suddenly can cause insomnia, nausea, and vomiting, and can trigger a relapse of bipolar symptoms.
Quetiapine vs. Other Bipolar Medications
| Quetiapine | Lamotrigine | Divalproex | |
|---|---|---|---|
| Mania | Approved | Not effective | Approved |
| Bipolar depression | Approved | Prevention (maintenance) | Limited |
| Sedation | Strong | Minimal | Moderate |
| Weight and metabolic effects | Common | Usually none | Common |
See our guides to lamotrigine (Lamictal) and divalproex (Depakote).
How We Approach Quetiapine at Samz Mental Health
- Use it where it’s approved and effective, such as bipolar mania, bipolar depression, or as an add-on when depression hasn’t responded
- Check baseline weight, blood sugar, and cholesterol, with lab work coordinated through your primary care provider or a local lab, and repeat them during treatment
- Use the lowest effective dose and watch for movement side effects
- Review the plan regularly through ongoing medication management
Can You Get Quetiapine Prescribed Online?
Yes. Quetiapine isn’t a controlled substance, so a licensed prescriber can prescribe it after a telehealth evaluation when appropriate, with monitoring labs drawn locally. Samz Mental Health offers video visits for adults physically located in Texas, New York, Florida, Colorado, Washington, Maryland, New Hampshire, New Mexico, and Iowa.
In-network with Aetna, Cigna, UnitedHealthcare, Optum, and Carelon Behavioral Health. See insurance details.
Frequently Asked Questions About Quetiapine
What is quetiapine used for?
Bipolar mania, bipolar depression, bipolar maintenance (add-on), schizophrenia, and, as Seroquel XR, add-on treatment for depression.
What is the quetiapine dose for bipolar depression?
300 mg in the evening, reached by day 4 starting from 50 mg.
Is quetiapine used for sleep?
Sometimes, off-label. Because of metabolic risks, other options are usually preferred for insomnia alone.
Does Seroquel cause weight gain?
It can, and blood sugar and cholesterol can rise, so they’re monitored.
How sedating is quetiapine?
Very; about half of people in bipolar trials reported drowsiness.
What monitoring is needed on quetiapine?
Weight, blood sugar, cholesterol, periodic eye exams, and watching for abnormal movements.
Can I drink alcohol on quetiapine?
No. It adds to sedation and dizziness.
Can I get quetiapine prescribed online?
Yes, after a telehealth evaluation, with labs drawn locally. Samz Mental Health sees patients by video in nine states.
Talk to a Provider About Bipolar or Depression Treatment
Book a video evaluation with a board-certified psychiatric nurse practitioner. Same-day appointments available. No referral needed.
References
- Seroquel XR (quetiapine extended-release) prescribing information. Drugs.com professional label; also on DailyMed.
Medical disclaimer: This page is for education and is not a substitute for a personal medical evaluation. Don’t start, stop, or change any medication without talking to your prescriber. If you’re in crisis or thinking about harming yourself, call or text 988 (Suicide & Crisis Lifeline) or call 911.