Quetiapine belongs to a class of medications known as antipsychotics. It is used to treat symptoms of schizophrenia, manic episodes associated with bipolar disorder, and depressive episodes associated with bipolar disorder. It works by affecting the actions of certain chemicals in the brain known as neurotransmitters.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The usual recommended starting dose for schizophrenia is 25 mg twice daily. Quetiapine is usually started with a low dose in order to allow the body to get used to it. This dose is increased as tolerated to a target dose of 150 mg twice daily. No more than 400 mg twice daily should be taken for schizophrenia as the safety of higher doses has not been established.

For manic episodes associated with bipolar disorder, the recommended starting dose is 50 mg twice daily. This dose is increased every day up to 400 mg twice daily as tolerated. Most people respond to doses between 200 mg and 400 mg twice daily.

For depressive episodes associated with bipolar disorder, the recommended starting dose is 50 mg once daily, usually at bedtime. This dose is increased every day up to 300 mg once daily as tolerated. Your doctor may continue to increase the dose as necessary, up to a maximum of 600 mg daily.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

Quetiapine can be taken with or without food. Do not stop taking this medication or change the time of the day you take it without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor to ensure that you are getting the maximum benefit from the medication. If you miss a dose by a few hours, take it as soon as possible and continue with your regular schedule. If most of the day has passed since the missed dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, and keep it out of the reach of children.

Quetiapine should not be taken by anyone who is allergic to quetiapine or to any of the ingredients of the medication.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain
• constipation
• diarrhea
• dizziness
• drowsiness
• dry mouth
• falls
• flu-like symptoms (e.g., sore throat, stuffy or runny nose)
• headache
• increased sense of hunger
• indigestion or upset stomach
• irritability
• lightheadedness or dizziness when rising from a lying or sitting position
• nausea
• stuffy or runny nose
• vomiting
• weakness
• weight gain

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• abnormal dreams, nightmares, sleepwalking, sleeping eating, or other sleeping behaviours
• abnormal muscle movements or stiffness
• blurred vision
• fainting
• feeling of slow, fast, or irregular heartbeat
• involuntary movements of face and tongue
• low body temperature (shivering, slurred speech, slow shallow breathing, weak pulse, confusion, memory problems)
• new or worsening constipation
• problems swallowing
• restless legs (an unpleasant sensation in the legs)
• shortness of breath
• signs of a blood clot in the arm or leg (tenderness, pain, swelling, warmth, or redness in the arm or leg) or lungs (difficulty breathing, sharp chest pain that is worst when breathing in, coughing, coughing up blood, sweating, or passing out)
• signs of infection (such as fever, chills, muscle aches, or sore throat)
• intestinal blockage (e.g., sudden abdominal cramping, abdominal pain, bloating, loss of appetite, nausea, vomiting, constipation or diarrhea)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools, skin rash, itching)
• skin rash with small red or purple bumps
• sleep apnea (interruptions in breathing while sleeping)
• speech changes
• swelling of arms, feet, or lower legs
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
• symptoms of muscle damage (e.g., unexplained muscle pain, tenderness or weakness, red-brown urine)
• urinary retention (inability to pass urine)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• long-lasting (more than 4 hours) and painful erection
• seizures (e.g., loss of consciousness with uncontrollable shaking)
• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
• signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
• signs of stroke (e.g., sudden or severe headache; sudden loss of coordination; vision changes; sudden slurring of speech; or unexplained weakness, numbness, or pain in arm or leg)
• symptoms of an allergic reaction (shortness of breath or difficulty breathing; hives; swelling of the eyes, mouth, lips, or throat)
• symptoms of a heart attack (e.g., chest pain or pressure, pain extending through shoulder and arm, nausea and vomiting, sweating)
• symptoms of neuroleptic malignant syndrome (e.g., high fever, muscle stiffness, increased heartbeat, and reduced consciousness)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should take this medication.

Blood cholesterol: Quetiapine has been associated with increased blood cholesterol levels. If you have elevated blood cholesterol levels, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Blood clots: This medication may increase the chance of blood clot formation, causing reduction of blood flow to organs or the extremities.

If you have a history of clotting you may be at increased risk of experiencing blood clot-related problems such as heart attack, stroke, or clots in the deep veins of your leg. Discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience symptoms such as sharp pain and swelling in the leg, difficulty breathing, chest pain, blurred vision, or difficulty speaking, contact your doctor immediately.

Body temperature: This medication, like other antipsychotic medications, can disrupt the body's ability to control body temperature. People who exercise vigorously, are exposed to extreme heat, are dehydrated, or are taking anticholinergic medications (e.g., benztropine, oxybutynin) are more at risk. Contact your doctor as soon as possible if you feel very hot and are unable to cool off.

Cataracts: Changes in the lens of the eye may develop with long-term use of quetiapine. Regular eye exams are recommended before and after treatment with this medication. If you notice any change in your vision, contact your physician as soon as possible.

Dependence/Tolerance: There have been reports of dependence, tolerance, misuse, and abuse of quetiapine. People with a history of drug or alcohol dependence should be closely monitored by their doctor while using this medication.

Diabetes: Like other antipsychotic medications, quetiapine may cause loss of control of blood sugars, making diabetes worse, or causing symptoms of diabetes to appear. If you have diabetes, discuss this link with your doctor. If you have diabetes or are at risk for diabetes (e.g., family history of diabetes, obesity), discuss with your doctor how this medication may affect your medical condition and whether any special monitoring is needed.

Drowsiness/reduced alertness: Quetiapine may cause dizziness and drowsiness. Avoid operating hazardous machinery (including cars) until you are certain that the medication does not impair your mental alertness, judgment, or physical coordination.

Enlarged prostate: This medication may worsen symptoms of an enlarged prostate, such as reduced urine flow. If you have a prostate condition, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Glaucoma: People with glaucoma (increased pressure in the eyes) may find that this medication makes the symptoms of glaucoma worse. If you have glaucoma, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Heart conditions: If you have a heart condition such as angina, heart failure, and irregular heartbeat, or have had a heart attack, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Heart rhythm: Quetiapine can cause changes to the normal rhythm of the heart, including an irregular heartbeat called QT prolongation. QT prolongation is a serious life-threatening condition that can cause fainting, seizures, and sudden death. If you are at risk for heart rhythm problems (e.g., people with heart failure, angina, low potassium or magnesium levels, or taking certain medications), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Hormonal changes: In rare instances, quetiapine can cause an increase in a certain hormone called prolactin and may lead to production of breast milk for women and altered monthly periods. It may also lead to swelling of the breasts for men. High levels of prolactin combined with a condition called hypogonadism, may increase the risk of osteoporosis for men and women.

Infection: Quetiapine can reduce the number of cells that fight infection in the body (white blood cells). Tell your doctor immediately if you notice signs of an infection, such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness. Your doctor will do blood tests regularly to monitor the number of specific types of blood cells in your blood.

Kidney problems: If you have kidney problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Quetiapine may also cause changes to liver function, including liver failure. If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Low blood pressure: Quetiapine may cause a lowering of blood pressure when rising from a sitting or lying position, or a racing heart rate, especially during the first few weeks of treatment. If you feel dizzy or lightheaded or feel your pulse is racing, and this feeling does not go away after a few minutes, call your doctor. Because this medication can cause dizziness or lightheadedness, do not get up too quickly after you have been sitting or lying for prolonged periods.

Movement disorders: There is a risk of developing tardive dyskinesia (TD), a condition where repetitive, uncontrollable, and purposeless movements (such as grimacing; tongue protrusion; lip smacking; puckering; rapid eye blinking; rapid movements of the arms, legs, and body trunk). If you experience any of these symptoms, contact your doctor immediately.

Neuroleptic malignant syndrome (NMS): A risk of developing this condition has been associated with antipsychotic medications, including quetiapine. If you experience increased sweating and sensations of warmth, muscle stiffness, emotional and behavioural changes, or irregular heartbeat, contact your doctor immediately. People taking this medication should take care to avoid becoming overheated or dehydrated.

Pancreatitis: Quetiapine can cause the pancreas to become inflamed. If you have a history of pancreatitis, gallstones, alcoholism, or high triglycerides, you may be more at risk of experiencing this. Report signs of pancreatitis such as abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, or swollen abdomen to your doctor immediately.

Seizures: If you have a history of seizures, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Skin reactions: In rare cases, quetiapine may cause severe skin reactions. These reactions may include a number of symptoms, including an extensive skin rash which may be itchy or have pustules, peeling, or scaling. In other cases, the reaction may include other organs in the body and cause fever, swollen glands, yellowing of the skin or eyes, or flu-like symptoms along with the skin rash. Get immediate medical attention if you have symptoms of a severe allergic or skin reaction.

Sleep apnea: This mediation may cause sleep apnea. If you have sleep apnea, or are taking medications which cause sedation or sleepiness, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Stopping the medication: Stopping this medication suddenly may cause symptoms such as difficulty sleeping, upset stomach, headache, diarrhea, vomiting, dizziness, and irritability. A gradual reduction in dose over a period of at least 1 or 2 weeks is recommended. If you are thinking of stopping the medication, check with your doctor first.

Suicidal or agitated behaviour: Adults and children taking this medication may feel agitated (restless, anxious, aggressive, emotional, and feeling not like themselves), or they may want to hurt themselves or others. These symptoms may occur within several weeks after starting this medication. If you experience these side effects or notice them in a family member who is taking this medication, contact your doctor immediately. Your doctor will monitor you closely for these side effects while you are taking this medication.

Thyroid changes: Quetiapine is associated with a decrease in thyroid hormone. If you have low thyroid (hypothyroidism), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: The safety of quetiapine use during pregnancy is not known. The use of this medication in the last 3 months of pregnancy has resulted in the newborn experiencing withdrawal effects including breathing problems, difficulty feeding, or irritability. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and taking quetiapine it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children and adolescents: The safety and efficacy of this medication have not been established for children under 18 years of age.

Seniors: There may be a higher risk of strokes, heart attacks, infections (e.g., pneumonia) and deaths associated with the use of antipsychotic medications by seniors. Talk to your doctor about the risks and benefits of using this medication. If you notice the following signs and symptoms, get medical attention immediately:

• signs of a stroke: sudden weakness or numbness in the face, arms or legs (often on one side of the body); speech problems; vision problems; balance problems or dizziness; confusion; sudden severe headache with no known cause
• signs of a heart attack: discomfort or pain in the chest, back, neck, jaw, arms, or stomach; sweating; shortness of breath; nausea; lightheadedness; feeling of impending doom.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over the counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.