HeadMeds gives young people in the United Kingdom general information about medication. HeadMeds does not give you medical advice. Please talk to your Doctor or anyone else who is supporting you about your own situation because everyone is different. Please read more important details about our site.

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Return to Quetiapine overview
  1. Use and Action
  2. Warnings and side effects
  3. Sex, drink, weight and everything else
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I have taken about eight different medications over the past five years as I battle my diagnoses

Quetiapine can be used to treat the following conditions

Headmeds fills the medicines information gaps for young people - things you might want to know about meds like will it affect my sex life? Can I still study?  Can I drink?
Headmeds does not give medical advice so this is just general information.
Each medicine has a balance of good and bad effects, and each person gets their own individual effects.
You might want to know just one thing about your medicine, but on each page we have given you the ‘safety headlines’. Please read them as they are important.

We have included lots of information about each medicine - but if you want all the details, please look at the patient information leaflet - which is inside every pack. These leaflets are also at www.medicines.org.uk - where there will be the most up-to-date information. Please be aware that the leaflets will only refer to the licensed use for your medicine. The leaflet will not mention any off label use - this includes off label conditions and also off label age groups.

Safety headlines

  • If you have taken more quetiapine than it said on the label, you must see a doctor quickly – even if you do not feel any different.
  • Whilst taking quetiapine, some people may think about hurting themselves or committing suicide. You must go straight to hospital with your tablets if you have any of these thoughts.
  • Quetiapine can sometimes cause serious side effects. Tell your doctor immediately if you experience unusual movements (mainly of the face or tongue). Feeling a little dizzy or sleepy is common, particularly at the start of treatment and this usually resolves, however if you feel very dizzy or excessively sleepy contact your doctor. Go to hospital if you have a seizure. Quetiapine can in rare cases cause a long-lasting and painful erection in men (called priapism). If this happens you will need to be treated in hospital. Very rarely severe allergic reactions can happen with quetiapine – go to hospital if you have difficulty breathing or swelling of your face or throat.
  • Quetiapine is not addictive, however stopping it suddenly can cause problems such as difficulty sleeping, feeling or being sick, headache, loose poo (diarrhoea), feeling dizzy or irritable. See you doctor if you want to stop, or if you are having these effects.
  • You might feel sleepy or dizzy, and not able to see properly, in the first few days after taking quetiapine – do not drive a car, ride a bike or operate machines until you see how this affects you.
  • If you are pregnant, or thinking of becoming pregnant, please read the pregnancy section (see “Sex, drink, weight and everything else”) because quetiapine may affect the developing baby.

Basic details

How does quetiapine work?

There is a naturally occurring chemical messenger ('neurotransmitter') in the brain called dopamine. Dopamine is the chemical messenger in the brain mainly involved with thinking, emotions, behaviour and perception. In some illnesses, there may be too much dopamine and this causes some of the symptoms of the illness. The main effect that quetiapine has is to block the effects of dopamine in the brain, resulting in a reduction of symptoms. Quetiapine also has effects on other neurotransmitters in the brain e.g. serotonin, and its beneficial effects may be related to this as well.

You should take quetiapine as agreed with your doctor

  • Take your medicine regularly every day to get the best effect.
  • Make sure that you know your dose. If it is not written on the label, check it with your pharmacist or doctor.
  • You will start with a low dose that increases slowly to a dose that is effective for you. This may take several days or weeks.
  • You will usually take your dose once or twice a day.
  • It doesn’t matter what time you take it each day - choose a time that you can always remember. This could be a mealtime, or when you brush your teeth.
  • You can take the ordinary tablets with or without food and they should be swallowed with a drink of water – the tablets have an unpleasant bitter taste if chewed.
  • The prolonged release (long-acting) tablets should not be broken as they have a special system in them to deliver the medicine into your body slowly over a few hours.
  • You should take the prolonged release (long-acting) tablets by swallowing them whole (do not chew or crush) with a glass of water on an empty stomach – one hour before food, or two hours after food.
  • Do not drink grapefruit juice while you are taking quetiapine, as it can increase the amount of quetiapine absorbed from the gut.

What should I do if I forget to take a dose of quetiapine?

What to do if you miss a dose of the tablets:

  • If you remember later during the day, take it as soon as possible.
  • If you forget to take it by your next dose, just take the next dose at the correct time. Do not try to catch up on missed doses.
  • Do not double dose.

What might happen?

  • If you forget to take your tablets for a few days, you may start getting your old symptoms back or some withdrawal symptoms. This means that you should talk to your doctor about it.

You must go to A&E if you take too much 

What to do if you take too much:

  • If you have taken more quetiapine than it said on the label, you must get help quickly – even if you do not feel any different.
  • Go to A&E. Take your medicine with you, to show to the doctors. Tell them how much you have taken.
  • Get a friend or family member to go with you, if you can, just in case you feel ill on the way.

 You might get any of the following signs:

  • feeling sleepy, feeling faint or dizzy, or having palpitations (a pounding heart beat)

It can take 4-6 weeks for quetiapine to give its full effect, but some people get good effects right from the first week

  • Many people say that it takes 4-6 weeks for quetiapine to show its full effect.
  • Some studies now, however, show a good effect for some people within the first week of taking the tablets.
  • You should stay in touch with your doctor to see how it goes over the first few weeks. They might do some tests to check your symptoms.
  • If you have had no good effects after 2-3 weeks, your doctor may increase the dose or change the medicine

Your doctor will start with a low dose that increases slowly to a dose that is effective for you. This may take several days or weeks.

Many people take quetiapine for a few years

You and your doctor should talk about how long you need to take quetiapine.

  • You may not get the full effect for several weeks.
  • If you take quetiapine for mania, bipolar depression or schizophrenia you will probably take it for a few years - otherwise your old symptoms can come back.
  • If you stop the medicine, you will go back for checks to see that your old symptoms do not come back.

The tablets contain lactose

  • The quetiapine tablets (ordinary or long-acting) may not be suitable for you if you have problems eating some sugars or dairy (milk-based) foods, as they contain lactose.

Reference sources

Search www.medicines.org.uk to find patient information leaflets and prescribing information on quetiapine. Quetiapine tablets have many Brands and the XL ones are the slow release preparations. The liquid is listed separately. The SmPC lists all the inactive ingredients in the product so you can check against any allergies. If you are still unsure about this then speak to your pharmacist.

  • British National Formulary (BNF) and British National Formulary for children. Download the BNF/BNFC app (blue background) on to your mobile device. No longer available for public access via the web 
  • Taylor D, Barnes T, Young A. Maudsley Prescribing Guidelines in Psychiatry, 13th edition. Oxford: John Wiley & Sons, May 2018. ISBN: 978-1-119-44260-8
  • Royal Pharmaceutical Society. Medicines Ethics and Practice (42nd edition). London: RPS, 2018. Standards for pharmacists to work to. It is not a free publication
  • World Anti Doping Agency WADA Prohibited List https://www.wada-ama.org/en/resources/science-medicine/prohibited-list-documents 
  • Choiceandmedication; an independent source of information on many mental health conditions and their medicines with easy to read fact sheets www.choiceandmedication.org Personal subscriptions to download the app available for £1 per month (with proportionate discounts for longer periods) but your local mental health Trust may subscribe and provide information sheets for free.
  • Best Use of Medicines in Pregnancy (BUMPS). Information sheets on drugs in pregnancy http://www.medicinesinpregnancy.org/ 
  • Drugs and Lactation Database (LactMed). Information on drugs in breastfeeding https://toxnet.nlm.nih.gov/newtoxnet/lactmed.htm
  • NICE CG178 Psychosis and Schizophrenia in adults. Feb 2014 (last updated Mar 2016). (https://www.nice.org.uk/guidance/cg178)  
  • NICE CG155 Psychosis and schizophrenia in children and young people. Jan 2013 (last updated Oct 2016). (https://www.nice.org.uk/guidance/cg155)