Quetiapine (Seroquel®)

This article provides a detailed overview of quetiapine, including the benefits, indications, side effects, drug interactions, and how it’s integrated into mental health treatment plans.

Key Takeaways:

• Quetiapine is the most commonly prescribed antipsychotic. The brand name for quetiapine is Seroquel®.

• Quetiapine is used for schizophrenia and bipolar disorder, as well as several other mental health conditions and symptoms, such as anxiety and insomnia. It mainly works by influencing levels of the neurotransmitters, dopamine and serotonin.

• Quetiapine has numerous possible side effects and drug interactions, several of which may be severe or dangerous in certain cases. It’s essential to talk with your doctor to make sure you receive the safest and most effective treatment plan.

Understanding Quetiapine

Quetiapine is a prescription antipsychotic medication. It is part of the second-generation antipsychotics, also known as atypical antipsychotics. Quetiapine helps treat psychosis and related symptoms, and it is used for several mental health conditions, including schizophrenia and bipolar disorder. ^[1]

How it Works

Quetiapine works by altering the level of specific neurotransmitters in your brain. It primarily blocks the effects of certain serotonin receptors, while also affecting levels of dopamine. These two neurotransmitters are involved in mood, thinking, behavior, and other vital components of mental health and general functioning. ^{[1] [2]}

To a lesser extent, quetiapine may also affect other neurotransmitters, including histamine, acetylcholine, and norepinephrine. ^[1]

Brand Names

The most common brand name of quetiapine is Seroquel®, which is also sold as Seroquel® XR.

Depending on the country, other brand names of quetiapine include Atrolak®, Biquelle®, Sondate®, and Zaluron®.

Conditions Quetiapine is Used For

Quetiapine is approved for several uses, including: ^{[1] [2]}

• Schizophrenia

• Acute mania within bipolar I disorder (BD-I)

• Depressive episodes in bipolar disorder

• BD-I maintenance

• Major depressive disorder (MDD)

• When combined with antidepressants

Quetiapine is also used off-label for several conditions, including: ^[1]

• Insomnia

• Alcohol dependence

• Generalized anxiety disorder (GAD)

• Chronic post-traumatic stress disorder (PTSD)

It is also used off-label as an adjunct treatment with selective-serotonin reuptake inhibitors (SSRIs) for the following conditions: ^[1]

• Obsessive-compulsive disorder (OCD)

• Borderline personality disorder (BPD)

• Aggression with psychiatric illness

• Symptoms of anxiety, insomnia, and agitation

How Common is It?

Quetiapine is a common antipsychotic medication. In fact, it is the most commonly prescribed antipsychotic medication overall. While this is attributed in part to approved uses, such as schizophrenia, many of the growing quetiapine prescriptions are off-label, such as for insomnia and anxiety. ^[3]

Quetiapine Side Effects

Quetiapine has many possible side effects, some of which may be severe. Possible side effects of quetiapine are: ^{[1] [2] [4] [5]}

• Dizziness

• Drowsiness

• Hypotension (low blood pressure)

• Especially orthostatic hypotension

• Increased heart rate

• Headache

• Agitation

• Fatigue

• Weight gain

• Abnormal cholesterol levels

• Increased blood sugar

• Dry mouth

• Increased appetite

• Trouble with balance

• Vomiting

• Constipation

• Gas

• Stomach pain

• Difficulty concentrating

Dangerous and Rare Side Effects

There are several rare side effects of quetiapine, some of which can be dangerous or even life-threatening. Examples of rare side effects of quetiapine include: ^{[1] [2] [4] [5]}

• Hyperprolactinemia (high prolactin levels), which can cause various symptoms, including:

• Enlarged breast tissue

• Missed periods

• Changes in libido and sexual function/performance

• Cataracts

• Increased blood pressure (in children)

• Painful, prolonged erections

• Confusion

• General sexual dysfunction (e.g. erectile dysfunction in men, inability to orgasm in women)

• Allergic reactions

• Unusual bleeding or bruising

• Extrapyramidal symptoms: A group of movement-related symptoms, such as:

• Tremors

• Muscle rigidity

• Shuffled walk

• Slurred speech

• Inability to sit still

• Tardive dyskinesia: This involves involuntary, repetitive movements, particularly of the face, mouth and tongue (e.g. lip smacking, tongue rolling, grimacing)

Some of the more serious possible side effects of quetiapine are: ^{[1] [2]}

• Neuroleptic malignant syndrome: This is a rare, but potentially life-threatening side effect. Symptoms include confusion, fever, severe muscle stiffness, and sweating.

• Heart arrhythmias: This refers to abnormal heart rhythms. It also increases the risk of sudden death

• Increased risk of suicidal thoughts and behaviors, primarily when treating individuals with MDD

• This risk is greatest in children and young adults under the age of 25

• The risks are also higher when individuals initially start quetiapine or have a change in dosage

Precautions

Quetiapine has greater risks in certain populations and thus should be used very cautiously or not at all in these cases. Quetiapine is not recommended for breastfeeding women, and it is only used during pregnancy if the benefits outweigh the risks. ^[1]

In other areas, quetiapine should be used very cautiously if you currently have or have a history of the following medical conditions and symptoms: ^{[1] [2] [4] [5]}

• Diabetes

• Metabolic syndrome

• Heart rhythm (and other cardiovascular) abnormalities

• Hypokalemia (low potassium)

• Hypomagnesemia (low magnesium)

• Low white blood cells

• Unable to fully empty your bladder

• Difficulty swallowing

• Trouble with balance

• Seizures

• Dementia-related psychosis (in the elderly)

• Cataracts

• High cholesterol

• Enlarged prostate

• High or low blood pressure

• Thyroid, heart, or liver disease

• Heart attack

• Stroke

Considerations and Risks

In addition to side effects and precautions, there are other important considerations. For example: ^{[4] [5]}

• Quetiapine may make you drowsy, thus increasing the risk of falls and injuries. It may be unsafe to drive, operate machinery, or perform other complex tasks.

• Quetiapine may make it harder for you to cool down when you’re hot or warm up when you’re cold.

• Quetiapine can increase the risk of developing metabolic syndrome, which is characterized by excessive weight and body fat, high blood sugar, high triglycerides, high blood pressure, and low levels of high-density lipoprotein (HDL) cholesterol

• You may experience high blood sugar, even if you don’t have diabetes. This risk is greater in individuals with schizophrenia

Drug Interactions

There are many important drug interactions to consider with quetiapine. Other drugs can affect the way quetiapine works, and quetiapine may also affect the way other drugs work. Specific drugs that may interact with quetiapine are: ^{[1] [2] [4]}

• Medications used to lower blood pressure, such as propranolol

• Antiarrhythmics (e.g. quinidine, dronedarone)

• Antipsychotics (e.g. chlorpromazine, thioridazine, iloperidone)

• Tricyclic antidepressants (e.g. doxepin, imipramine)

• Opioids (e.g. levomethadyl, methadone)

• Antifungal medications (e.g. ketoconazole)

• Antibiotics (e.g. erythromycin)

• Anti-seizure medications (e.g. phenytoin, carbamazepine)

This is not an exhaustive list. Always tell your doctor any prescription drugs you currently take or have ever taken.

Other Interactions

In addition to prescription drugs, quetiapine may also interact with other substances, including: ^{[4] [5]}

• Alcohol

• St. John’s wort

• Tobacco/nicotine

• Certain illegal drugs

• Antihistamines for allergies, coughs, or colds

• Grapefruit and grapefruit juice

In addition to prescription medications, tell your doctor all of the substances you take, including over-the-counter medicines, herbs, and dietary supplements.

Quetiapine Dosage

Quetiapine is available in extended-release (ER) and immediate-release (IR) forms. The ER tablets are taken once daily, while the IR tablets are taken two to three times daily. In all cases, quetiapine is taken orally.

Here are common dosage guidelines for quetiapine: ^[1]

• Schizophrenia:

• IR: 150 to 750mg, divided into two to three daily doses

• ER: 400 to 800mg once per day, in the evening.

• BD-I (manic):

• IR 200 to 400mg twice per day.

• BD-I (manic/mixed):

• ER: 400 to 800mg once per day, in the evening

• Acute depressive bipolar disorder:

• IR: 300mg daily at bedtime

• ER: 300mg at bedtime

It’s important to note that these doses represent a typical range. Most times, your doctor will start you on a low dose and gradually increase it over several weeks to carefully determine the ideal dosage with the highest benefits-to-risks ratio. ^[1]

In most cases, initial doses start as low as 25 to 50mg. The maximum dose per day is 800mg. ^[1]

What to Do if You Forget a Dose

If you forget to take your dose of quetiapine, take it as soon as possible. However, if it is almost time to take your next dose, simply wait until that time. Do not double-up on doses of quetiapine. ^[2]

Note that these are typical guidelines. Always consult your doctor to determine exactly what you should do in cases of a missed dose.

What to Do in the Event of an Overdose

An overdose on quetiapine can be serious and life-threatening. If this happens, call your doctor or your location’s emergency number as soon as possible. Another option is to call your location’s poison control center.

Make sure you’re aware of these phone numbers and have direct access to them, so you can use them promptly if they’re needed.

Quetiapine and Integrated Therapy

In many cases, psychotherapy is integrated with quetiapine treatment to promote the best outcomes in mental health and overall well-being. Various forms of psychotherapy may be used, such as cognitive-behavioral therapy (CBT), dialectical behavior therapy (DBT), or exposure therapy, depending on the specific mental health condition and other individual factors.

Psychotherapy may help you to better understand and manage your thoughts, feelings, and behaviors. It can also be used to develop and implement key skills that improve life quality and daily functioning, such as stress management, emotional regulation, and social/interpersonal skills. ^[6]

Therefore, even though schizophrenia, bipolar disorder, and the main symptoms of psychosis are treated predominantly by medication, psychotherapy still holds a valuable role and offers benefits in unique areas not addressed by medication alone.