Olanzapine

Please do not be worried by the side effects listed on this page. Some people take olanzapine without any side effects or 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 mirtazapine, then you should discuss this with your doctor, nurse, or pharmacist.

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

• 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 difficulty in breathing.
• Any combination of fever, faster breathing, sweating, muscle stiffness and drowsiness or sleepiness.
• Another possible, but not very common, side-effect of olanzapine is repeating movements of the tongue, mouth and face.
• This is called tardive dyskinesia.
• The first sign might be some movements of your tongue that you cannot control, and they may be quite regular and rhythmic.
• The problem with tardive dyskinesia is that it might not stop, even if you stop taking your medicine.
• If you notice it early and take action with your doctor, the problem should not get worse.

Go to see your doctor straight away.

Some side-effects that do appear should get better after a few days. If they do not, you should go back to your doctor.

Some side-effects of olanzapine may – strangely - seem like other mental health symptoms. Some side-effects here are also the opposites of each other. The balance of chemicals in the brain is very fragile, and hard to control! If they do not get better after a few days on the tablets, go back to the doctor.

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

Tell your doctor or pharmacist before you take olanzapine if you have any of these conditions.

You need to talk to your doctor or pharmacist if you have, or have a history of:

• 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
• Fits (Seizures, epilepsy)
• Glaucoma
• Respiratory (lung) diseases

Olanzapine does not mix well with some other medicines and drugs. 

Tell your doctor before you take olanzapine if you take:

• Carbamazepine (an anti-epileptic and mood stabiliser)
• Fluvoxamine (an antidepressant)
• Ciprofloxacin (an antibiotic)
• medicines for diabetes
• Lithium
• Blood pressure medicines
• Benzodiazepines (such as lorazepam, diazepam, clonazepam, or temazepam)
• Sleeping tablets (such as zopiclone, zolpidem, or temazepam)
• Ritonavir (a HIV medicine)
• Valproate (sodium valproate or valproic acid, also known as Epilim or Depakote)
• Parkinson’s disease medicines
• Heart rhythm medicines (also known as anti-arrhythmic medicines)
• Epilepsy medicines
• Methadone
• Metoclopramide (an anti-sickness medicine)
• Opioid painkillers (such as codeine, dihydrocodeine, tramadol, morphine, oxycodone, fentanyl, or buprenorphine

It may be necessary to change your medicine dose.

• If you take any antidepressants, medicines to help to relieve anxiety or to help you sleep, they may make you very sleepy if taken with olanzapine.

If you have any further questions about this you should speak to your doctor or pharmacist.

Always talk to the doctor if you are taking other medicines.

Tell the pharmacist you are taking olanzapine if you buy medicines (including things you put on your skin) for common illnesses.

Get your weight and blood checked regularly when you are taking olanzapine.

• You will have your weight checked, and have some blood tests, when you start taking olanzapine.
• You should then have your weight, blood sugar, blood fats, blood pressure and pulse measured regularly during early treatment, then at least 6 monthly or annually thereafter depending on your age.
• You should also have your blood sugar tested when you start, after one month, and then every 4-6 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, and whether a young woman’s periods are regular.
•  It is very important to go for these checks when you are asked to do so.

Olanzapine use has been linked to high blood sugar and diabetes in some young people.

• Some studies have shown a risk of developing diabetes among young people who are taking olanzapine.
• This could be linked to putting on weight.
• Watch out for any early signs of diabetes:
• wanting to drink a lot
• going for a wee a lot
• feeling more hungry
• feeling weak
• If you are a young person who already has diabetes, taking olanzapine may affect your blood sugar levels.
• Talk to your doctor, and check your blood glucose levels regularly.
• You may have to increase the medication you use for your diabetes.

Young people were more likely than adults to experience weight gain and to have changes in their blood fats, cholesterol and prolactin hormone while taking olanzapine.

Olanzapine does not mix well with drugs.

• Antipsychotics block the effect of dopamine, so this means the ‘high’ may not be as ‘high’ as before from any drug.
• You may be tempted to increase your dose of the drug to make up for it, but this could be dangerous.
• Cannabis can make drowsiness worse with olanzapine, and can also make your symptoms worse.
• Methadone can make drowsiness worse with olanzapine and potentially cause dangerous problems with the rhythm of your heart.
• All antipsychotics can reduce the stimulant effects of cocaine.

Stopping the medication causes the balance of chemicals in the brain to alter

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

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

• 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.
• People usually take olanzapine for a long time, to keep those symptoms away.
• You may get your old symptoms back if you stop olanzapine for a while.
• You can also get side-effects including sweating, difficulty sleeping, shaking, anxiety, or feeling or being sick.
• It is better to agree stopping with a doctor who will reduce you gradually.
• This will take 1-2 weeks.
• You will probably go for checks with your doctor after you stop olanzapine to check that you still feel better.

Reference sources

• Zyprexa tablets SPC last updated 18.10.16 Available online
  http://www.medicines.org.uk/emc/medicine/614 accessed 18/01/2017
• Zyprexa tablets PIL last updated 17.10.16 Available online http://www.medicines.org.uk/emc/medicine/14159 accessed 18/01/2017
• Zypadhera injection SPC last updated 18.01.16 Available online http://www.medicines.org.uk/emc/medicine/21361 accessed 18/01/17
• British National Formulary (BNF) 72nd edition, 2016.
• British National Formulary for Children (BNFc) 2016-2017, 2016.
• Taylor D, Paton C, Kapur S. Maudsley Prescribing Guidelines in Psychiatry, 12th edition. Oxford: John Wiley & Sons, 2015
• WADA Prohibited List 2015. Available online at http://list.wada-ama.org/ accessed 12.08.2015.
• Neal MC. Medical Pharmacology at a Glance (7th Edition). Oxford: John Wiley & Sons, 2012
• Royal Pharmaceutical Society of Great Britain. Medicines Ethics and Practice (37th edition). London: RPS, 2013
• Bumps – best use of medicines in pregnancy. Olanzapine Jan 2015. Accessed via http://www.medicinesinpregnancy.org/Medicine--pregnancy/Olanzapine/
• www.choiceandmedication.org accessed 12.08.15 (normally accessible for free via your mental health trust website.
• NICE CG178 Psychosis and Schizophrenia in adults. Feb 2014. Available online www.nice.org.uk
• NICE CG155 Psychosis and schizophrenia in children and young people. Jan 2013. Available online www.nice.org.uk
• NICE CG185 Bipolar disorder: assessment and management. Sep 2014. Available online www.nice.org.uk