How does this medication work? What will it do for me?

Quetiapine belongs to a class of medications known as antipsychotics. It is used to treat symptoms of schizophrenia, manic and depressive episodes associated with bipolar disorder, and symptoms of depression after failed treatment with antidepressant medications. 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.

What form(s) does this medication come in?

50 mg
Each peach-coloured, capsule-shaped, biconvex tablet, intagliated with "XR 50" on one side and plain on the other, contains quetiapine fumarate equivalent to quetiapine free base 50 mg. Nonmedicinal ingredients: hydroxypropyl methylcellulose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium citrate; coating: hydroxypropyl methylcellulose, polyethylene glycol 400, red ferric oxide, titanium dioxide, and yellow ferric oxide.

150 mg
Each white, capsule-shaped, biconvex tablet, intagliated with "XR 150" on one side and plain on the other, contains quetiapine fumarate equivalent to quetiapine free base 150 mg. Nonmedicinal ingredients: hydroxypropyl methylcellulose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium citrate; coating: hydroxypropyl methylcellulose, polyethylene glycol 400, titanium dioxide.

200 mg
Each yellow, capsule-shaped, biconvex tablet, intagliated with "XR 200" on one side and plain on the other, contains quetiapine fumarate equivalent to quetiapine free base 200 mg. Nonmedicinal ingredients: hydroxypropyl methylcellulose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium citrate; coating: hydroxypropyl methylcellulose, polyethylene glycol 400, titanium dioxide, and yellow ferric oxide.

300 mg
Each pale yellow, capsule-shaped, biconvex tablet, intagliated with "XR 300" on one side and plain on the other, contains quetiapine fumarate equivalent to quetiapine free base 300 mg. Nonmedicinal ingredients: hydroxypropyl methylcellulose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium citrate; coating: hydroxypropyl methylcellulose, polyethylene glycol 400, titanium dioxide, and yellow ferric oxide.

400 mg
Each white, capsule-shaped, biconvex tablet, intagliated with "XR 400" on one side and plain on the other, contains quetiapine fumarate equivalent to quetiapine free base 400 mg. Nonmedicinal ingredients: hydroxypropyl methylcellulose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium citrate; coating: hydroxypropyl methylcellulose, polyethylene glycol 400, titanium dioxide.

How should I use this medication?

The usual recommend starting dose for schizophrenia or manic episodes associated with bipolar disorder is 300 mg once daily on day one, 600 mg once daily on day two, and up to a maximum of 800 mg once daily from day three onwards.

The usual recommended starting dose for depressive episodes associated with bipolar disorder is 50 mg once daily on day one, 100 mg once daily on day two, 200 mg once daily on day three, and 300 mg once daily on day four and onwards. The dose may be further increased depending on response and tolerability. The maximum dose is 600 mg daily.

When treating a manic episode of bipolar disorder, the usual recommended starting dose is 300 mg taken once daily on day one, 600 mg taken once daily on day two and up to a maximum of 800 mg on day three.

The usual recommended starting dose for major depressive disorder is 50 mg once daily on days one and two, then 150 mg once daily on day three. The dose may be further increased up to a maximum of 300 mg per day depending on response and tolerability.

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. The tablet should be swallowed whole with some water or other fluid. Do not chew or crush this medication, as this will increase the amount of medication your body absorbs at a single time and will cause side effects.

Do not stop taking this medication or change the time of the day you take it without consulting your doctor. Quetiapine XR is usually taken in the evening.

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.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

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

What side effects are possible with this 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.

  • constipation
  • dizziness
  • drowsiness
  • dry mouth
  • headache
  • indigestion or upset stomach
  • irritability
  • lightheadedness or dizziness when rising from a lying or sitting position
  • vomiting
  • 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 and nightmares
  • abnormal muscle movements or stiffness
  • blurred vision
  • difficulty passing urine
  • feeling of slow, fast, or irregular heartbeat
  • feeling more hungry
  • involuntary movements of face and tongue
  • new or worsening constipation
  • problems swallowing
  • restless legs (an unpleasant sensation in the legs)
  • signs of bleeding in the stomach (e.g., bloody, black, or tarry stools; spitting up of blood; vomiting blood or material that looks like coffee grounds)
  • signs of infection (such as fever, chills, muscle aches, or sore throat)
  • 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)
  • sleep apnea (episodes where you stop breathing during sleep)
  • swelling of arms, feet, or lower legs
  • symptoms of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
  • symptoms of a blood clot (e.g., swelling, redness, warmth, and pain in an arm or leg; sudden chest pain; difficulty breathing; and pounding heart beat)
  • symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
  • unusual tiredness or weakness

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

  • fainting
  • long-lasting (more than 4 hours) and painful erection
  • seizures (e.g., loss of consciousness with uncontrollable shaking)
  • 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 neuroleptic malignant syndrome (e.g., high fever, muscle stiffness, increased heart beat, 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.

Are there any other precautions or warnings for 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 and triglyceride 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 changes: Quetiapine can cause a decrease in white blood cells, red blood cells (blood cells that carry oxygen), or platelets (blood cells that help form blood clots). If you have a history of low white blood cells, anemia, or blood clotting 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.

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: Quetiapine can disrupt the body's ability to control body temperature. People who exercise vigorously, who 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.

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.

Diabetes: Quetiapine may cause an increase in blood sugar levels (may cause a loss of blood glucose control) and glucose tolerance may change. People with diabetes may find it necessary to monitor their blood sugar more frequently while using this medication.

If you have diabetes or are at risk for developing diabetes, 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.

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.

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.

Hormonal changes: Quetiapine, in rare instances, can cause an increase in the hormone called prolactin, which may lead to production of breast milk in women and altered monthly periods. It may also lead to swelling of the breasts in men.

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 problems: 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 has been reported to cause liver failure, which has in rare cases, caused death. This medication may also cause a decrease in liver function. 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 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, 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.

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.

If you have a history of pancreatitis, gallstones, alcoholism, or high triglycerides, you may be more at risk of experiencing this.

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.

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 one 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.

Weight gain: Quetiapine is associated with an increase in body weight. Your doctor may monitor you for weight changes while you are taking this medication.

Pregnancy: The safety of quetiapine use during pregnancy is not known. 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 a breast-feeding mother and are 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 less than 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.

What other drugs could interact with this medication?

There may be an interaction between quetiapine and any of the following:

  • abiraterone acetate
  • aclidinium
  • alcohol
  • aldesleukin
  • aliskiren
  • alpha blockers (e.g., alfuzosin, doxazosin, tamsulosin)
  • alpha agonists (e.g., clonidine, methyldopa)
  • amiodarone
  • amphetamines (e.g., dextroamphetamine, lisdexamphetamine)
  • angiotensin converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
  • angiotensin receptor blockers (ARBs; e.g., candasartan, irbesartan, losartan)
  • antihistamines (e.g,. cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
  • antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
  • anti-Parkinsons medications (e.g., amantadine, apomorphine, bromocriptine, levodopa, pramipexole, ropinirole)
  • antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
  • aprepitant
  • atropine
  • azelastine
  • "azole" antifungal medications (e.g., fluconazole, ketoconazole)
  • belladonna
  • benztropine
  • beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
  • bicalutamide
  • bosentan
  • brimonidine
  • buprenorphine
  • calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
  • cannabis
  • chloral hydrate
  • chloroquine
  • cisapride
  • conivaptan
  • cyclosporine
  • deferasirox
  • dexamethasone
  • dextromethorphan
  • diabetes medications (e.g., chlorpropamide, glipizide, glyburide, insulin, metformin, nateglinide, rosiglitazone)
  • disopyramide
  • dofetilide
  • domperidone
  • donepezil
  • dronabinol
  • dronedarone
  • ergot alkaloids (e.g., ergotamine, dihydroergotamine)
  • enzalutamide
  • famotidine
  • fingolimod
  • flavoxate
  • flecainide
  • formoterol
  • galantamine
  • general anesthetics (medications used to put people to sleep before surgery)
  • glucagon
  • guanfacine
  • glycopyrrolate
  • granisetron
  • hepatitis C protease inhibitors (e.g., boceprevir, simeprevir, telaprevir)
  • HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delaviridine, efavirenz, etravirine, nevirapine)
  • HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
  • indacaterol
  • ipratropium
  • ketotifen
  • lithium
  • macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
  • magnesium sulphate
  • mefloquine
  • methylphenidate
  • metoclopramide
  • metronidazole
  • mifepristone
  • minoxidil
  • mirtazapine
  • mitotane
  • modafinil
  • monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, rasagiline, selegiline, tranylcypromine)
  • muscle relaxants (e.g., cyclobenzaprine, methocarbamol, orphenadrine)
  • nabilone
  • narcotic pain relievers (e.g., codeine, fentanyl, morphine, oxycodone)
  • nefazodone
  • nitrates (e.g., nitroglycerin, isosorbide dinitrate, isosorbide mononitrate)
  • octreotide
  • octreotide
  • olopatadine
  • ondansetron
  • orphenadrine
  • oxybutynin
  • paliperidone
  • pasireotide
  • pentamidine
  • perampanel
  • pimozide
  • procainamide
  • propafenone
  • quinidine
  • quinine
  • quinolone antibiotics (e.g., ciprofloxacin, norfloxacin, ofloxacin)
  • rifampin
  • rivastigmine
  • romidepsin
  • St. John's Wort
  • salmeterol
  • scopolamine
  • seizure medications (e.g., clobazam, ethosuximide, felbamate, levetiracetam, phenobarbital, phenytoin, primidone, topiramate, valproic acid, zonisamide)
  • SSRI antidepressants (e.g., citalopram, fluoxetine, sertraline)
  • serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., desvenlafaxine, duloxetine, venlafaxine)
  • sleeping medications (e.g., zolpidem, zopiclone)
  • stiripentol
  • sulfamethoxazole
  • tacrolimus
  • tamoxifen
  • tapentadol
  • tetrabenazine
  • tetracycline
  • tiotropium
  • tolterodine
  • tramadol
  • trazodone
  • tricyclic antidepressants (e.g., amitriptyline, desipramine)
  • trimethoprim
  • triptorelin
  • tyrosine kinase inhibitors (e.g., dasatinib, imatinib, nilotinib)
  • "triptan" migraine medications (e.g., eletriptan, sumatriptan)
  • tryptophan
  • umeclidinium
  • vardenafil
  • warfarin

If you are taking any of these 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.

Medications other than those listed above may interact with this medication. 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.