Your guide to medication Olanzapine

Many people take olanzapine for a few years.

How long you need to take it will depend on what condition you are taking it for.

You and your doctor should talk about how long you need to take olanzapine before you start your treatment.

If you stop the olanzapine, you will go back for checks to see that your old symptoms do not come back.

For psychosis or schizophrenia, if you have had one episode of illness, then it is best for you to keep taking olanzapine for at least two years to reduce the chances of becoming ill again. If you have had more than one episode of illness, then a period of at least five years is recommended.

If you are taking olanzapine to treat bipolar mania or bipolar depression, then you will need to discuss long-term medicines for your bipolar disorder with your doctor. This is to help stop the illness coming back.

For bipolar disorder, it is important to remain on medicines in the long term because every time you become ill, there is more chance of you becoming ill again. Olanzapine can be used as a long-term medicine, but there are other choices and lithium is still thought to be the best long-term medicine for bipolar disorder. You should discuss your options with your doctor.

For schizoaffective disorder, it is probably best to keep taking the olanzapine for several years to reduce the chances of the illness coming back. We know less about schizoaffective disorder, but it has some similarities to bipolar disorder and some similarities to schizophrenia.

Depression is usually treated with an antidepressant medicine, and olanzapine is sometimes added to an antidepressant for more severe depression. For people with severe depression, it is best to continue the antidepressant medicine for at least two years to stop the illness from coming back. The doctor is likely to recommend continuing olanzapine for the same length of time.

You will get the best effect from olanzapine if you take it every day at the dose prescribed by your doctor.

Make sure that you know your dose. If it is not written on the label, check with your pharmacist or doctor.

You may start with a low dose that increases slowly to your regular dose over the next few days.

You will usually take your dose once a day.

It is usually recommended to take olanzapine at bedtime because it can cause sleepiness as a side effect.

However, it is important to choose a time of day to take it that you can easily remember, which could be bedtime, a mealtime, or when you brush your teeth.

You can take it before or after food.

For the plain-coated tablets, swallow them whole with a drink of water - if you chew them, they taste bitter.

Put orodispersible tablets (melts) on your tongue and let them dissolve there. You can also dissolve these in a glass of water, orange juice, apple juice or milk and then drink it all down.

A doctor or nurse can give you an injection in your bottom that provides a long-lasting dose of olanzapine, lasting for two or four weeks. You may need to take tablets alongside the injection, especially while the dose builds up. Every time you have the injection, you will be asked to wait at the centre for at least three hours so that they can check that the injection is not giving you too much olanzapine in one go. The good thing about a long-acting injection is that you don’t have to remember to take so many tablets every day. It is slowly working in your body all the time between injections.

If you remember later during the day, take it as soon as possible.

If you forget to take it by bedtime, just start again on the next day. Do not take a double dose.

If it is less than 12 hours before your next dose of olanzapine, then do not take the missed dose because taking the doses too close together could cause more side effects.

If you miss your appointment for your injection, contact your doctor or nurse straight away to make another appointment.

It is very important to have the injection every two or four weeks.

If you forget to take your tablets for a while, or you miss an injection, you may start getting your old symptoms back. You should talk to your doctor if this happens.

Once you start taking an antipsychotic, the brain adjusts to having a new level of dopamine around. If you stop taking the antipsychotic all at once, the balance starts to change again. You could get your old symptoms back.

Stopping this medicine quickly, or reducing the dose too much at once, may cause your old symptoms to come back, or cause you some withdrawal effects.

You can stop taking it safely with your doctor’s help.

People usually take olanzapine for a long time, to keep their symptoms away.

You may get your old symptoms back if you stop olanzapine for a while. You can also get withdrawal effects, including:

• difficulty sleeping
• feeling or being sick

It is better to agree stopping with a doctor who will reduce your dose gradually. This is likely to take a few weeks.

You will probably go for checks with your doctor after you stop olanzapine to check that you still feel better. 

If you have taken more olanzapine than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately – even if you do not feel any different.

Olanzapine can sometimes cause serious side effects. Tell your doctor immediately if you experience unusual movements (mainly of the face or tongue).

Go to hospital immediately if you think you may have developed a blood clot (symptoms are usually swelling, pain and redness in the leg) - a clot may travel through blood vessels to the lungs causing chest pain and difficulty breathing.

Also go to hospital and tell the doctor you are taking olanzapine if you develop a combination of fever, faster breathing, sweating, muscle stiffness or drowsiness.

Stopping olanzapine suddenly can cause withdrawal effects and stopping it too early could cause your illness to come back. See your doctor if you want to stop taking olanzapine because it is better to come off it gradually.

You might feel sleepy or dizzy in the first few days after taking olanzapine. 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 (under the 'Side Effects' tab) because olanzapine may affect the developing baby.

If you have taken more olanzapine than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately – 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 to go with you, if you can, just in case you feel ill on the way.

You might get any of the following signs:

• rapid beating of the heart
• agitation/aggressiveness
• problems with speech
• unusual movements (especially of the face or tongue)
• reduced level of consciousness or coma
• confusion
• seizures (fits)
• a combination of fever, faster breathing, sweating, muscle stiffness and drowsiness or sleepiness, slower breathing, aspiration (breathing in vomit, mucus, or blood), high blood pressure or low blood pressure, and unusual rhythms of the heart

Go to a doctor or hospital straight away if you get any of the following symptoms while taking olanzapine:

• allergic reactions (difficulty breathing, swelling of your face or throat, itching skin lumps)
• glaucoma (increased pressure inside your eyes, which can damage your vision) – symptoms include eye pain, red eyes, headache, tenderness around the eyes, blurred vision, and seeing rings around lights
• swelling, pain, and redness in the leg, which may be from a blood clot. Such a clot could travel through blood vessels to the lungs causing chest pain and breathing difficulties
• any combination of fever, faster breathing, sweating, muscle stiffness and drowsiness or sleepiness
• repetitive, regular movements of the tongue, mouth and face that you’re not able to control. This condition is called ‘tardive dyskinesia’ and is extremely rare but can be very serious. It may not stop even when you stop taking the medication. If you notice it early and act with your doctor, the problem should not get worse

You need to talk to your doctor or pharmacist before starting treatment with olanzapine if any of the following apply to you:

• stroke or “mini” stroke (temporary symptoms of stroke)
• Parkinson’s disease
• prostate problems
• a blocked intestine (paralytic ileus)
• liver or kidney disease
• any blood disorders
• heart disease
• diabetes
• seizures (fits)
• glaucoma
• respiratory (lung) diseases

You should have your weight, blood sugar, blood fats, blood pressure and pulse measured regularly during early treatment, then at least every six months to a year after that, depending on your age.

You should also have your blood sugar tested when you start, after one month, and then every four to six months after that.

The doctor might also check your heart with an electrocardiogram (ECG) and check your blood pressure.

They might also check your height and development. If you have periods, they may also check whether they are regular.

It is very important to go for these checks when you are asked to do so.

Please do not be worried by the side effects listed on this page. Some people take olanzapine without any side effects or with only a few mild side effects. Some side effects wear off after a few days or weeks.

If you think you might be getting a side effect from olanzapine, then you should discuss this with your doctor, nurse, or pharmacist.

Do not stop taking the tablets until you talk to your doctor, or you may get withdrawal symptoms as well.

Very common side effects of olanzapine (affecting more than one in ten people) include:

• weight gain
• increases in the levels of prolactin in the blood (seen only in blood tests)
• feeling dizzy or faint with a slow heart rate, especially when getting up from a lying or sitting position. This usually happens at the start of your treatment and will normally pass on its own (speak to your doctor if it doesn't)

Common side effects of olanzapine (affecting up to one in ten people) include:

• changes in the level of some blood cells, chemicals, circulating fats and, in early treatment, temporary increases in liver enzymes (seen only in blood tests)
• increased appetite
• tremor, muscle stiffness or unusual muscle movements
• dry mouth
• loss of strength or extreme tiredness
• water retention leading to swelling of the hands, ankles or feet
• joint pain
• sexual problems such as feeling less like having sex less and problems getting an erection

Olanzapine use has been linked to an increased risk of developing diabetes among some young people. Symptoms include:

• putting on weight
• needing to wee a lot
• needing to drink a lot
• feeling weak
• raised blood sugar levels

If you already have diabetes, you may need to increase the amount of medication you take for this alongside taking olanzapine.