Zyprexa is a medicine containing the active substance olanzapine. It is available as tablets (round and white: 2.5, 5, 7.5 and 10 mg; blue and oval: 15 mg; pink and oval: 20 mg) and as a powder to be made up into a solution for injection.
|Table of Contents|
|What is it used for?|
|How is it used?|
|How does it work?|
|How has it been studied?|
|What benefits has it shown during the studies?|
|What is the risk associated?|
|Why has it been approved?|
Zyprexa is used to treat adults with schizophrenia. Schizophrenia is a mental illness that has a number of symptoms, including disorganised thinking and speech, hallucinations (hearing or seeing things that are not there), suspiciousness and delusions (mistaken beliefs). Zyprexa is also effective in maintaining improvement in patients who have responded to an initial course of treatment. Zyprexa is also used to treat moderate to severe manic episodes (extremely high mood) in adults. It can also be used to prevent the recurrence of these episodes (when symptoms come back) in adults with bipolar disorder (a mental illness with alternating periods of high mood and depression) who have responded to an initial course of treatment.
Zyprexa is usually taken by mouth, but the injection can be used for the rapid control of agitation or disturbed behaviour in adults with schizophrenia or a manic episode, when taking the medicine by mouth is not appropriate.
The medicine can only be obtained with a prescription.
The recommended starting dose of Zyprexa tablets depends on the disease being treated: 10 mg per day is used in schizophrenia and in the prevention of manic episodes, and 15 mg per day in the treatment of manic episodes, unless it is used with other medicines, in which case the starting dose can be 10 mg per day. The dose is adjusted according to how well the patient responds to and tolerates the treatment. The usual dose range is between 5 and 20 mg per day.
The usual dose when using the injection is 10 mg as a single injection into a muscle. This can be followed if needed by a further injection of 5 or 10 mg two hours later.
Lower doses may be needed for patients over 65 years of age (5 mg per day for the tablets and 2.5 to 5 mg for the injection) and for patients who have problems with their liver or kidneys (5 mg per day for both the tablets and injection).
In all cases, the maximum dose of Zyprexa that can be given in a day, using tablets or injection, is 20 mg.
The active substance in Zyprexa, olanzapine, is an antipsychotic medicine. It is known as an ?atypical? antipsychotic because it is different from the older antipsychotic medicines that have been available since the 1950s. Its exact mechanism of action is unknown, but it attaches to several different receptors on the surface of nerve cells in the brain. This disrupts signals transmitted between brain cells by ?neurotransmitters?, chemicals that allow nerve cells to communicate with each other. It is thought that olanzapine?s beneficial effect is due to it blocking receptors for the neurotransmitters 5-hydroxytrypamine (also called serotonin) and dopamine. Since these neurotransmitters are involved in schizophrenia and in bipolar disorder, olanzapine helps to normalise the activity of the brain, reducing the symptoms of these diseases.
In schizophrenia, Zyprexa tablets have been studied in about 3,000 adults, in which their effectiveness was compared with that of placebo (a dummy treatment) or haloperidol (another antipsychotic medicine). All four studies lasted six weeks, but the patients stayed on the medicine for up to a year or more.
In the treatment of acute manic episodes in adults with bipolar disorder, Zyprexa tablets were compared with placebo, haloperidol or valproate (another medicine used in manic episodes) in five studies, including one where patients were also receiving other medicines. In the prevention of manic episodes, Zyprexa tablets were studied in 1,162 adults. Their effectiveness was compared with that of placebo or lithium (another medicine used in bipolar disorder).
The injection was studied in 581 adults with schizophrenia (compared with placebo or injected haloperidol) and 228 manic adults (compared with placebo or injected lorazepam, another medicine used in manic episodes).
In all studies, the effectiveness of Zyprexa was assessed using various symptom rating scales.
In all studies, Zyprexa as tablets and as injections was more effective at improving symptoms than placebo. Zyprexa tablets were at least as effective as the medicines they were compared with for the treatment of schizophrenia (haloperidol), the treatment of moderate to severe manic episodes (haloperidol and valproate), and the prevention of recurrence in patients with bipolar disorder (lithium). The injection was also shown to be more effective than lorazepam (at a relatively low dose) in manic patients, and as effective as haloperidol in schizophrenia.
The most common side effects with Zyprexa (seen in more than 1 patient in 10) are somnolence (sleepiness), weight gain and raised levels of prolactin (a hormone). For the full list of all side effects reported with Zyprexa, see the Package Leaflet.
Zyprexa should not be used in people who may be hypersensitive (allergic) to olanzapine or any of the other ingredients. Zyprexa should not be used in patients at risk of narrow-angle glaucoma (raised pressure inside the eye).
The Committee for Medicinal Products for Human Use (CHMP) decided that Zyprexa?s benefits are greater than its risks, in adults, for the treatment of schizophrenia, including the maintenance of clinical improvement during continuation therapy in patients who have shown an initial treatment response, the treatment of moderate to severe manic episode, the prevention of recurrence in patients with bipolar disorder, and for the injection, the rapid control of agitation or disturbed behaviour in patients with schizophrenia or a manic episode, when oral therapy is not appropriate. The Committee recommended that Zyprexa be given marketing authorisation.