Quetiapine

You should experience some benefits within the first one to two weeks of taking it, but it can take four to six weeks, sometimes longer, for quetiapine to show its full effects. This can vary between individuals and the reason why you are taking it.

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 at all after two weeks, you should talk to your doctor about your progress. They may recommend increasing the dose or changing your medicine. Don’t increase your dose yourself if you think the medication isn’t working.

Your doctor will start with a low dose, which they will increase slowly until you find a dose that is effective for you. This may take several days or weeks.

Quetiapine can cause weight loss or weight gain. Weight gain is more common than weight loss.

The risk of weight gain with quetiapine is lower compared to other antipsychotic medicine (like olanzapine), but children and young people appear to be more at risk of this side effect compared with adults. You may also be more likely to gain weight if you have not taken this type of medication before.

It is very difficult to know how it will affect each person who takes it. Talk to your doctor or pharmacist if you are concerned about your weight, or changes to your weight, while taking quetiapine. They can review your medicine with you and look at any changes that could be made to help.

Making sure you do enough exercise and eat a healthy diet (with vegetables and fibre) can help you to avoid putting on too much weight.

Mental health conditions like schizophrenia and bipolar disorder can make being active and eating healthily more of a challenge. Talk to your doctor, pharmacist and specialist healthcare team for lifestyle advice and where to get support if this would be helpful.

If you do gain weight, most of this is likely to occur in the first six months of treatment. It is possible you may continue to gain weight after this time, but the rate of weight gain will usually be slower. This can happen even if you are taking a very low dose.

Quetiapine can also affect the way your body processes sugar. A side effect of quetiapine includes high blood sugar and, while not common, has been linked to the development or worsening of diabetes in some young people. This could also be linked to putting on weight.

It is important to watch out for symptoms that might mean your body is having trouble processing sugar. These include wanting to drink a lot, going for a wee a lot, and feeling very weak or tired all the time. If you develop these symptoms, or any other symptoms you are concerned about, it is important to make an appointment with your doctor to discuss this.

If you already have diabetes, taking quetiapine may affect your blood sugar levels. Talk to your doctor and check your blood glucose levels regularly if this applies to you. You may have to increase the medication you use for your diabetes.

You may want to let your family and friends know you are taking quetiapine so they can support you and help you look out for side effects.

In the first few days of taking quetiapine, you may feel extremely sleepy.

Reported side effects of quetiapine include strange dreams or nightmares.

Rarely, quetiapine can also cause sleep-talking and sleep-walking. Some people have also done other activities while they were asleep, like eating.

If you have been taking quetiapine for more than a month and you continue to feel very sleepy during the day (or your sleep at night is worse), you should go back to your doctor and discuss what changes could be made to help. This may include switching to a different medication.

Alcohol

It may be possible to drink some alcohol in moderation while taking quetiapine but having the two together might make you very sleepy and unsteady on your feet, especially when you first start taking the medication.

During the first few weeks, it might be best to stop drinking alcohol until you see how the medicine affects you.

If you want to drink alcohol, it’s best to only drink small amounts, and have a plan for getting home safely if you go out.

Drinking alcohol every day, or in large amounts, can make your symptoms worse and may mean you won’t get the maximum benefit from your medication.

Street drugs

Some street drugs like cocaine and ecstasy can increase levels of dopamine in the brain. As antipsychotics block the effects of dopamine, the 'high' from street drugs may not be as 'high' as before. So you may be tempted to increase the dose of your street drug to make up for it, but this could be dangerous.

Cannabis and other drugs may have their own side effects on your mental health, like anxiety or psychosis.

Some street drugs can make you feel sleepy and this could be made worse with quetiapine.

Quetiapine can enhance the effects of some street drugs and has itself been abused for this purpose. Do not share your quetiapine with anyone else. If someone is asking you to give away or sell your medicine, please ask your parent, teacher or doctor to help you.

There are many other street drugs, but we don’t know what effect taking them with quetiapine will have, so it’s best to be cautious. There is no regulation of street drugs or ‘legal highs’, so even if there are no known issues with the medication you take, the supply you receive might be mixed with other substances that could be dangerous.

Get more advice on our drugs and alcohol guide.

Quetiapine does not mix well with some other medicines, including herbal medicines.

Always talk to the doctor if you are taking other medicines. Tell the pharmacist you are taking quetiapine if you buy medicines for common illnesses, including things you put on your skin.

Look at the leaflet inside your medicine box for more information about other medicines that can interact with quetiapine. With some medicines your doctor may need to adjust the dose of quetiapine if you take them together. Ask a doctor or pharmacist for more information if you have any questions.

Do not drink grapefruit juice while you are taking quetiapine, as it can increase the amount of drug absorbed from the gut.

There are multiple companies that manufacture this medicine and the non-active ingredients may vary between products and also between the different strengths of tablets that are available. Always let your pharmacist know if you have any food allergies or intolerances, and always check with them if you’re concerned about any of the ingredients in your medication.

The tablets contain lactose so they may not be suitable for you if you have problems eating some sugars or dairy products.

The oral solution (liquid) contains sucralose. This should not affect your blood sugar if you’re diabetic.

If you need to avoid animal products, please note that non-active ingredients used in the production of medicines may sometimes be of animal origin. Ask your pharmacist if you have any questions about the ingredients.

Further information about practical considerations for medicines if you need to avoid animal products can be found on the Vegan Society website.

Taking quetiapine may make you feel tired or dizzy and may affect your eyesight when you start taking it.

This could affect you if you drive a car, ride a bike, or do anything else that needs a lot of focus. It might be best to stop doing these things for the first few days or weeks until you know how it affects you.

Most people drive as normal while taking quetiapine. If you are worried about this or have any concerns you would like to discuss, speak to your doctor or pharmacist.

You must tell The DVLA (Driver and Vehicle Licensing Agency) if you have bipolar disorder, schizophrenia, schizoaffective disorder or other mental health conditions that could affect your driving. You can be fined if you do not tell DVLA about a medical condition that affects your driving and may be prosecuted if you are involved in an accident as a result.

Pregnancy

If you become pregnant while you are on quetiapine, you should carry on taking it and make an appointment to see your doctor as soon as possible. They can discuss the benefits and risks of continuing quetiapine and help you to make a decision that is best for you and your baby.

They may refer you to a specialist perinatal mental health team to support you with this decision.

You can find out more information about taking quetiapine during pregnancy at Bumps (Best Use of Medicines in Pregnancy).

Untreated illness can also be harmful to you and your developing baby, so decisions about stopping or avoiding medication when you are pregnant need to be discussed carefully with your doctor. If you and your doctor agree that it is best for you to continue taking quetiapine while pregnant, you should tell your midwife. If you are planning to get pregnant, it is recommended that you take folic acid while you are trying for a baby and during pregnancy. It is safe to take this together with quetiapine.

Quetiapine can slightly increase your chance of getting high blood pressure in pregnancy (pre-eclampsia), gaining weight and gestational (pregnancy-linked) diabetes. Let your midwife know you are taking quetiapine so they can monitor you during pregnancy and birth.

Blood clots are also a rare side effect of taking quetiapine. To reduce your risk of a blood clot, your doctor of midwife might suggest using a medicine to prevent this.

Post-natal

If quetiapine is taking in the last three months of pregnancy, there can be symptoms the baby is born with. They are usually mild and don’t last long. But speak to your doctor or midwife if your baby has feeding difficulties, is restless or has breathing problems.

Breastfeeding

Quetiapine is passed to the baby in breastmilk in small amounts.

If your baby was born early, then breastfeeding while you are taking quetiapine may not be recommended. Talk to your midwife and doctor about feeding options.

If you breastfeed whole taking, seek urgent medical advice if your baby becomes restless, very sleepy or developing feeding problems.

Sex

Quetiapine can have side effects that might affect your sex life. Although they are very, they include:

• not feeling like you want to have sex
• swelling of the breasts and (very rarely) some milk flow, regardless of gender
• changes to your period
• getting a painful erection that could last a long time (priapism). If this happens, go to hospital for treatment.

Untreated mental illness can have a negative effect on your sex life, so if quetiapine helps you to recover, positive effects can include improving your desire, experience and enjoyment of sex as your mood lifts and you become interested in life and relationships again.

Fertility

There is currently no evidence to show that quetiapine will affect your fertility.

It can increase a naturally occurring hormone in your body called prolactin. If you have raised levels of prolactin this can impact your fertility, no matter your gender. For people who menstruate, it may cause your periods to stop or become irregular. This can make getting pregnant harder.

Let your doctor know if you’re planning on getting pregnant and taking quetiapine. They can monitor your prolactin levels.

Quetiapine is not a banned substance in sport. However, it can produce a false positive result in some drug tests, including urine tests for methadone. Talk to your doctor about this if it is a problem for you.

Most people play sports as normal while taking quetiapine, but if quetiapine affects your concentration, eyesight or co-ordination, then you may want to wait to see if those effects go away before playing sports that need a lot of focus. If you have any concerns, discuss this with your doctor.

Quetiapine may affect your concentration, give you blurred eyesight and make you feel dizzy and tired.

Ideally it is best not to take quetiapine for the first time just before your exams.

It is not possible to predict how the medication will make you feel, and if you do get any side effects, these are more likely to occur when you first start taking quetiapine.

You should talk to your doctor about any future exams if you are starting quetiapine. You might decide together to delay starting it until you have done them.

If they are more than a month away, however, you might find that it is better to start quetiapine to improve your motivation and ability to study.

Most people take exams as normal while taking quetiapine, but if you have any concerns, discuss this with your doctor.