Health Centres - Zyprexa (olanzapine)
How does it work?
Zyprexa tablets, velotabs and injection all contain the active ingredient olanzapine, which is a type of medicine known as an atypical antipsychotic.
Olanzapine works in the brain, where it affects various neurotransmitters, in particular serotonin (5HT) and dopamine. Neurotransmitters are chemicals that are stored in nerve cells and are involved in transmitting messages between the nerve cells.
Dopamine and serotonin are neurotransmitters known to be involved in regulating mood and behaviour, amongst other things. Psychotic illness is considered to be caused by disturbances in the activity of neurotransmitters (mainly dopamine) in the brain. Schizophrenia is known to be associated with an overactivity of dopamine in the brain, and this may be associated with the delusions and hallucinations that are a feature of this disease.
Olanzapine works by blocking the receptors in the brain that dopamine acts on. This prevents the excessive activity of dopamine and helps to control schizophrenia.
Schizophrenic patients may experience 'positive symptoms' (such as hallucinations, disturbances of thought, hostility) and/or 'negative symptoms' (such as lack of emotion and social isolation). Olanzapine is effective in relieving both positive and negative symptoms of schizophrenia, whereas the conventional antipsychotics are usually less effective against the negative symptoms.
Olanzapine is also used to treat moderate to severe episodes of mania in people with bipolar affective disorder (manic depression). In people whose manic episode is controlled with olanzapine, the medicine may also be used long-term as a mood stabiliser to prevent further manic and depressive episodes of bipolar disorder.
Zyprexa injection is used when rapid control of agitation and disturbed behaviours is needed for people with schizophrenia or a manic episode. Once behaviour has been controlled, the treatment is usually switched to oral treatment with Zyprexa tablets or Zyprexa velotabs. Zyprexa velotabs are tablets that are designed to dissolve on the tongue and be swallowed with the saliva, without the need for water.
What is it used for?
-
Schizophrenia.
- Moderate to severe manic episodes of manic depression.
- Stabilising mood to prevent episodes of mania or depression in people with bipolar affective disorder whose manic episode has responded to olanzapine treatment.
Warning!
- This medicine may cause drowsiness or dizziness. If affected do not drive or operate machinery. Alcohol should be avoided.
- Unless your doctor tells you otherwise, you should not suddenly stop taking this medicine, even if you feel better and think you don't need it any more. This is because the medicine controls the symptoms of the illness but doesn't actually cure it. This means that if you suddenly stop treatment your symptoms could come back. Stopping the medicine suddenly may also rarely cause withdrawal symptoms such as sweating, anxiety, nausea, vomiting, difficulty sleeping or tremor. When treatment with this medicine is stopped, it should be done gradually, following the instructions given by your doctor.
- This medicine can occasionally cause your blood pressure to drop when you move from a lying down or sitting position to sitting or standing, especially when you first start taking the medicine. This may make you feel dizzy or unsteady. To avoid this try getting up slowly. If you do feel dizzy, sit or lie down until the symptoms pass.
- This medicine can cause some people to put on weight. Talk to your doctor about this before you start treatment so that you can discuss strategies, such as diet and exercise, for minimising any weight gain.
- Your doctor may want to monitor your weight, blood sugar and cholesterol levels and liver function while you are taking this medicine.
- People over the age of 65 years should have their blood pressure regularly monitored while taking this medicine.
- The components of tobacco smoke can cause certain medicines to be removed from the body faster than normal. If you are a smoker and are giving up smoking while taking this medicine, let your doctor know, as your dose of this medicine may possibly need to be altered.
- Consult your doctor immediately if you experience abnormal movements, particularly of the face, lips, jaw and tongue, while taking this medicine. These symptoms may be indicative of a rare side effect known as tardive dyskinesia, and your doctor may ask you to stop taking this medicine, or decrease your dose.
- Consult your doctor immediately if you experience the following symptoms while taking this medicine: high fever, sweating, muscle stiffness, faster breathing and drowsiness or sleepiness. These symptoms may be due to a rare side effect known as the neuroleptic malignant syndrome, and your treatment may need to be stopped.
- People who cannot take phenylalanine or mannitol should note that Zyprexa velotabs contain aspartame, which is a source of phenylalanine, and mannitol. Seek advice from your doctor if this applies to you.
- Zyprexa velotabs contain the preservatives sodium methyl parahydroxybenzoate and sodium propyl parahydroxybenzoate, which may cause an allergic reaction in some people. An allergic reaction may cause an itchy rash or shortness of breath, and may occur as soon as you start treatment, or after you have taken the medicine for some time. Consult your doctor if you experience these symptoms.
- There is no information regarding the use of this medicine in children and adolescents under the age of 18.
- This medicine is not licensed or recommended for treating behavioural problems or psychoses in people with dementia, as it may increase the risk of stroke in this group of patients.
- This medicine is not recommended for treating psychotic symptoms caused by dopamine agonist medicines in people with Parkinson's disease, as it may make the psychotic symptoms and Parkinson's symptoms worse.
Use with caution in
- Elderly people.
- Decreased kidney function.
- Decreased liver function.
- People with raised liver enzymes.
-
Diabetes and people at risk of diabetes.
-
Enlarged prostate gland .
- Failure of function of part of the gut causing an obstruction in the intestines (paralytic ileus).
- Low white blood cell count (leucopenia).
- Low level of a type of white blood cell called a neutrophil in the blood (neutropenia).
- People taking other medicines that can affect liver function or white blood cells.
- People with decreased production of blood cells by the bone marrow due to chemotherapy, radiotherapy or illness.
- People with a history of decreased blood cell production caused by a medicine.
- Diseases or conditions involving increased production of blood cells or bone marrow tissue.
- History of fits (seizures), eg epilepsy.
- Abnormal heart rhythm seen on the heart monitoring trace as a 'prolonged QT interval'.
- Irregular heartbeat caused by very rapid contraction of the top two chambers of the heart (atrial fibrillation).
-
Heart failure.
- Thickening of the walls of the heart (cardiac hypertrophy).
- Low blood magnesium levels (hypomagnesaemia).
- Low blood potassium levels (hypokalaemia).
- History of or risk of stroke or small temporary strokes.
-
High blood pressure .
Not to be used in
- People with a known risk for closed-angle glaucoma.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of this medicine for use during pregnancy has not been established. It is not recommended for use in pregnancy unless considered essential by your doctor. If you get pregnant or plan to get pregnant while taking this medicine you should seek medical advice from your doctor.
- This medicine passes into breast milk and could be harmful to a nursing infant. Women who need to take this medicine should not breastfeed their infants. Seek medical advice from your doctor.
Label warnings
- This medication may cause drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drink.
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