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Seroquel side effects, warnings, interactions, and how to avoid them

Seroquel belongs to a class of drugs called atypical antipsychotics. It is FDA approved to treat schizophrenia and bipolar disorder. It is also used off-label to treat depression, anxiety, and other conditions.
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By | Updated on Mar. 14, 2022 Medically reviewed by Karen Berger, Pharm.D.

Seroquel side effects | Weight gain | Liver function | Serious side effects | Diabetes and high blood pressure | Extrapyramidal effects | Neuroleptic malignant syndrome | How long do side effects last? | Warnings | Interactions | How to avoid side effects

Seroquel is a brand-name prescription drug for the treatment of schizophrenia and bipolar disorder in adults, adolescents, and children. Also available in an extended-release format (Seroquel XR), Seroquel is commonly used off-label to treat other mental illnesses including major depressive disorder, generalized anxiety disorder, and others. The active ingredient in Seroquel, quetiapine fumarate, belongs to a class of drugs called atypical antipsychotics. 

Antipsychotics calm the brain by blocking the neurotransmitter dopamine, reducing overexcitement in the brain that causes many of the symptoms of schizophrenia and bipolar mania. Because Seroquel affects how the brain works, it may not be the right medication for some people. Side effects, existing medical conditions, and drug interactions may cause problems.

RELATED: What is Seroquel?

Common side effects of Seroquel

The most common side effects of Seroquel include:

  • Drowsiness
  • Dry mouth
  • Weight gain
  • Headache
  • Dizziness
  • Fatigue and tiredness
  • High cholesterol
  • High triglycerides
  • Constipation
  • Sudden drop in blood pressure when standing (orthostatic hypotension)
  • Fast heartbeat
  • Abdominal pain
  • Sore throat
  • Stuffy nose
  • High prolactin levels
  • Joint pain
  • Low blood pressure

Weight gain

Atypical antipsychotics such as Seroquel are associated with the side effect of metabolic changes, including weight gain. (Other metabolic changes include high blood sugar and high cholesterol.) Patients who take Seroquel will be monitored by their healthcare professional for weight changes. In children who take Seroquel, weight changes will be compared to weight changes expected for normal growth.

Liver function

Abnormal liver function tests can be a common side effect of Seroquel. In most cases, there are no symptoms, and although the abnormal tests may appear quickly, they often return to normal with continued treatment. Liver function will be monitored regularly during treatment with Seroquel. Note: People who have liver problems will be prescribed Seroquel will caution, and the healthcare provider will start at a low dose, slowly increasing if needed.

Serious side effects of Seroquel

Serious side effects can occur as well. Some serious side effects may be delayed or long-term. The most serious side effects of Seroquel include:

  • High blood pressure
  • Suicidal thoughts
  • Worsening of depression
  • Drug-induced movement problems (extrapyramidal effects)
  • High glucose (hyperglycemia)
  • Stroke
  • Seizures
  • Heart rate irregularities 
  • Diabetes
  • Severe body temperature dysregulation (hypothermia or hyperthermia)
  • Underactive thyroid (hypothyroidism)
  • Cataracts or lens changes
  • Intestinal obstruction
  • Neuroleptic malignant syndrome (NMS)
  • Muscle damage
  • Difficulty swallowing
  • Low white blood cell counts
  • Severe allergic reactions

Seroquel and diabetes/high blood sugar

Seroquel can cause high blood sugar, also known as hyperglycemia. High blood sugar can happen in people who already have diabetes, or in people that have never had diabetes. Symptoms of high blood sugar include:

  • Increased hunger and thirst 
  • Increased urination
  • Feeling weak or tired
  • Stomach illness
  • Confusion
  • Fruity-smelling breath

Patients who experience these symptoms should call their healthcare provider immediately. High blood sugar can lead to serious and life-threatening complications, including coma or death. Patients who have diabetes or risk factors for diabetes will be monitored closely for changes in blood sugar during Seroquel treatment.

Seroquel and extrapyramidal effect

Drugs like Seroquel that block dopamine frequently cause a wide range of movement disorders called extrapyramidal effects. The most common include:

  • Involuntary muscle contractions (dystonia)
  • Muscle twitching (dyskinesia)
  • Repetitive jerking of facial and neck muscles (tardive dyskinesia)
  • Urgent hard-to-control restless movements (restless legs syndrome, finger tapping, squirming, marching back and forth, teeth grinding)
  • Parkinsonism (symptoms similar to Parkinson’s disease: tremor, slow movements, muscle stiffness, stooped posture)

While atypical antipsychotics such as Seroquel are less likely to cause extrapyramidal effects, they are still a possibility and are more likely at higher doses. Approximately 0.1% to 5.6% of patients taking Seroquel will experience dystonia, another 0.1% to 5.5% will experience parkinsonism, 0.1% to 3.8% will experience muscle twitching, 2% report restless legs syndrome, and 0.1% to 1% will experience tardive dyskinesia. 

Seroquel and neuroleptic malignant syndrome

Neuroleptic malignant syndrome (NMS) is a potentially life-threatening side effect of antipsychotic drugs that block dopamine in the brain, including Seroquel. The overall incidence among people taking antipsychotics and similar drugs is 0.1% to 3.2%, but research has not determined the likelihood of NMS in people taking Seroquel. Watch for signs such as:

  • Fever
  • Rigid muscles
  • Excessive sweating
  • Confusion
  • Changes in blood pressure, heartbeat, or breathing

Neuroleptic malignant syndrome requires immediate treatment to prevent serious complications or death.

How long do side effects last?

The active ingredient in Seroquel, quetiapine, has a half-life of six to seven hours. This is the time it takes the body to eliminate half a dose of quetiapine from the body, so an entire dose is eliminated in about 30 hours. Most common side effects of quetiapine such as drowsiness, dry mouth, dizziness, constipation, headache, fatigue, and postural hypotension will fade within that time. 

Many of the metabolic effects of quetiapine such as high cholesterol, high triglycerides, high blood sugar, underactive thyroid, and weight gain may take several days or longer to return to normal. Some metabolic effects such as diabetes may evolve into chronic, lifelong conditions. 

Serious side effects such as extrapyramidal symptoms, severe allergic reactions, heart rate irregularities, low white blood cell counts, neuroleptic malignant syndrome, and changes to eye lenses may require medical treatment and the discontinuation of Seroquel to improve. Extrapyramidal symptoms can clear up quickly or may be long-term, lasting for years after stopping the medication. Stroke, heart problems, and neuroleptic malignant syndrome may cause lifelong complications.

Seroquel contraindications & warnings

Not everyone is a good candidate for Seroquel. Physical and medical conditions may reduce the safety or effectiveness of the drug.

Abuse and dependence

The U.S. Food and Drug Administration (FDA) does not classify quetiapine as a controlled substance with a risk of abuse or dependence. Doctors are, however, advised to monitor patients for signs of Seroquel abuse or tolerance.

The sudden discontinuation of Seroquel may bring on withdrawal symptoms such as insomnia, nausea, and vomiting. It is recommended to seek medical advice from a healthcare professional before discontinuing Seroquel.

Overdose

A quetiapine overdose can cause symptoms such as:

  • Drowsiness
  • Sedation
  • Fast heartbeat
  • Low blood pressure
  • Delirium
  • Coma

Seek emergency medical treatment if too much Seroquel is taken.

Restrictions

Because of potentially serious problems, anyone with allergies to quetiapine will not be given Seroquel. In addition, senior patients with dementia-related psychosis should avoid Seroquel. Other medical or physical conditions can also cause problems, so healthcare providers will use the drug cautiously and possibly monitor its effects more closely. These conditions include:

  • Seniors with dementia-related psychosis will not be given Seroquel or any other antipsychotic drug for that condition.
  • Children, adolescents, and young adults with major depressive disorder should be carefully watched by both healthcare providers and caretakers for signs of worsening depression or suicidality when taking Seroquel.
  • People with irregular heartbeat, heart disease (history of heart attack or other heart problems), history of stroke, or cerebrovascular disease will require extra monitoring when given Seroquel.
  • People with diabetes, high cholesterol, or high triglycerides will need regular blood tests to monitor any changes in serum glucose, cholesterol, or fats.
  • People with low blood pressure, low blood volume, or dehydration.
  • Many people take Seroquel because they experienced neuroleptic malignant syndrome or extrapyramidal symptoms on other antipsychotics. They will need to be watched carefully for any new symptoms of NMS or extrapyramidal effects while taking Seroquel.
  • People with a history of seizures will need to be monitored for seizures.
  • People with a history of low white blood cell counts may require routine blood tests to monitor Seroquel’s effects on their white blood cell counts.
  • Quetiapine can worsen urination problems, prostate problems, and constipation.
  • People with a history of pneumonia or aspiration pneumonia will need to carefully monitor and report any problems with swallowing.
  • People with liver disease may require lower doses.

Pregnancy and nursing

Babies exposed to antipsychotics during the third term of a pregnancy are at an increased risk of withdrawal symptoms and extrapyramidal side effects (involuntary movement problems) when they’re born. Expectant mothers may need to discuss with a healthcare provider the risks and benefits of taking Seroquel during the third trimester. Otherwise, there is no evidence that quetiapine causes birth defects or miscarriage when taken during pregnancy.

Quetiapine is present in breast milk in very small amounts, but there is no evidence of any harm to a breastfeeding infant.

Children

The Food and Drug Administration (FDA) has approved quetiapine to treat schizophrenia in adolescents as young as 13 years of age and to treat manic episodes in children diagnosed with bipolar I disorder as young as 10 years of age. It is not approved for use in children for any other condition. There is, however, an increased risk of worsening depression or suicide in children with major depressive disorder.

Seniors

People older than 65 years can take Seroquel in the same doses as younger adults, though starting doses may need to be smaller and increased more slowly than in younger adults. Some older adults may need to be monitored or tested regularly for side effects.

Seroquel interactions

Because Seroquel works on the central nervous system, it has a number of drug interactions that can cause problems. Certain drugs are never combined with Seroquel, but others may require dosing changes or careful monitoring for side effects. 

  • CONTRAINDICATED: The antipsychotic medications pimozide and thioridazine are never given with Seroquel because the combination raises the risk and severity of Seroquel’s most severe side effects.
  • Antipsychotic drugs: All antipsychotic drugs cause side effects similar to Seroquel’s side effects, so taking more than one antipsychotic increases the risk and severity of side effects.
  • Depressants: Seroquel slows down the brain. This helps calm schizophrenia and manic episodes, but it also causes sedation, drowsiness, lightheadedness, and similar problems. CNS depressants that also significantly increase the sedative effects of Seroquel include sleeping pills, barbiturates, anxiety medications, opioid pain relievers, muscle relaxants, benzodiazepines, and alcohol.
  • Drugs that increase the side effects of quetiapine: The strongest CYP3A4 inhibitors such as the antifungal drugs ketoconazole or itraconazole may require the quetiapine dose to be reduced by six times the regular dose.
  • Drugs that reduce the effectiveness of quetiapine: Drugs such as phenytoin, carbamazepine, or rifampin may require the quetiapine dose to be increased to six times the normal dose.
  • Blood pressure medications and diuretics: Quetiapine can lower blood pressure, so extra monitoring will be required when combined with blood pressure medications and diuretics.
  • Drugs that affect heart rhythm: Drugs that can affect the heart’s rhythm include antiarrhythmic medications, amphetamines, macrolide antibiotics, and opioids such as tramadol and methadone.
  • Diabetes medications: Quetiapine can raise glucose levels and interfere with the effectiveness of diabetes drugs. 
  • Parkinson’s disease medications: Parkinson’s disease is treated by increasing dopamine levels, but quetiapine and other antipsychotic drugs block dopamine, reducing the effectiveness of Parkinson’s treatments and worsening Parkinson’s symptoms.

Seroquel and serotonin syndrome 

Serotonin syndrome is a life-threatening condition caused by the buildup of serotonin in the body. Serotonin syndrome can present with symptoms that range from mild to life-threatening and requires emergency medical attention. 

Certain drugs are more commonly associated with serotonin syndrome, such as antidepressants, opioid pain medications, and triptan migraine medications. However, Seroquel can also be associated with serotonin syndrome. 

Symptoms to look out for include agitation, hallucinations, feeling overheated, muscle twitching, and fast heart rate. Serotonin syndrome can occur with normal doses of a drug, and is more likely to occur when a dose is increased, or if too much drug is taken (accidentally or on purpose), or when more than one drug associated with serotonin syndrome is being taken. Always tell your healthcare provider about all of the medications you take, including Rx and OTC drugs, vitamins, and supplements. Do not start any new medications unless your healthcare provider is aware and gives you the green light to do so.

How to avoid Seroquel side effects

Unfortunately, most people taking Seroquel or any other antipsychotic drug will experience one or more side effects. Even so, there are ways to minimize side effects.

1. Tell the healthcare provider about all medical conditions and medications

The healthcare provider who is prescribing an antipsychotic can help minimize side effects if they know about all medical conditions, especially:

  • Diabetes or a family history of high blood sugar
  • High cholesterol or triglycerides
  • High or low blood pressure
  • Heart problems
  • Low white blood cell counts
  • High prolactin levels
  • Any history of depression, mood problems, or suicidality
  • Any heart problems or heart rhythm problems
  • Liver disease
  • Thyroid problems
  • Constipation or urination problems
  • Pregnancy or plans to get pregnant
  • Breastfeeding or plans to breastfeed

Some side effects are caused or worsened by combining Seroquel with other prescription or over-the-counter drugs. Keep a list of all medications being taken and share it with the healthcare provider prescribing Seroquel. 

2. Take Seroquel as directed

Take Seroquel exactly as instructed. Doses will vary, particularly at the beginning of therapy. In order for Seroquel to work, doses must be taken every day following a daily schedule. Don’t skip a dose. Take a missed dose unless it is almost time for the next dose. In that case, skip the missed dose and take the next dose on time.

3. Keep all appointments

You will need to see a healthcare provider regularly and may need to take blood and other tests. Keep all these appointments. They are the first line of defense in spotting and managing side effects before they become serious problems.

4. Don’t drink alcohol

Seroquel is a sedative and causes sleepiness, dizziness, and other impairments. Drinking will only worsen these side effects, increasing the risk of falling, accidents, and injury.

5. Be careful about driving and other risky activities

As a sedative, Seroquel can make driving and similar activities dangerous. Avoid driving until an effective dose is reached and its effects on alertness and focus are well understood.

6. Remove falling hazards from the home

Falls and injuries are a common problem when taking Seroquel, particularly for older adults. Doctors are advised to perform a fall risk assessment when prescribing Seroquel. When taking Seroquel, try to remove obstacles around the house that may cause falls. A number of devices can help make areas of the house safer.

7. Avoid getting overheated or too cold

Quetiapine interferes with the body’s ability to regulate temperature. Stay out of the sun or overly cold weather. If the weather is too hot, stay indoors where it’s cool. Avoid overexertion and dress appropriately for the temperature.

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