Generic Name: clozapine
Product Name: Clozaril
Indication: What Clozaril is used for
Clozaril is used to treat schizophrenia, which is a mental illness with disturbances in thinking, feelings and behaviour.
Clozaril is only used to treat patients suffering from schizophrenia when other antipsychotic medicines either have not worked or have caused severe side effects.
Ask your doctor if you have any questions about why Clozaril has been prescribed for you. Your doctor may have prescribed it for another reason.
Clozaril is available only with a doctor’s prescription. There is no evidence that it is addictive.
Clozaril is not recommended for use in children or adolescents under the age of 16, as there is not enough information on its use in that age group.
Action: How Clozaril works
Clozaril belongs to a group of medicines called antipsychotics. It helps to correct chemical imbalances in the brain which may cause mental illness.
Clozaril has weak D2 and D1 receptor-blocking activity, but potent noradrenolytic, anticholinergic, antihistaminic and arousal reaction inhibiting effects. It has also been shown to possess antiserotonergic properties.
Clozaril tablets contain 25 mg or 100 mg of the active ingredient, clozapine.
They also contain colloidal anhydrous silica, purified talc, magnesium stearate, lactose monohydrate, maize starch and povidone.
Dose advice: How to use Clozaril
Before you take Clozaril
When you must not take it
Do not take Clozaril if you have an allergy to clozapine, the active ingredient, or to any of the other ingredients of Clozaril listed here.
Some of the symptoms of an allergic reaction may include shortness of breath, wheezing or difficulty breathing; swelling of the face, mouth and throat, as well as the tongue, which may be itchy or painful; or swelling of other parts of the body; rash, itching or hives on the skin.
If you think that you are allergic to Clozaril, ask your doctor for advice before taking this medicine.
Do not take Clozaril if you have a low white blood cell count or have previously had a low white blood cell count caused by a medicine (except if it was following a treatment for cancer). Clozaril can cause agranulocytosis (a condition with a reduced number of white blood cells.) These cells are needed to fight infections. If you have a low white blood cell count or have had one in the past, you must not take Clozaril.
Do not take Clozaril if you are unable to have regular blood tests.
Before starting this medicine and during your therapy, checks will be required to monitor the levels of various components in your blood. Your doctor will tell you when these tests are needed.
Do not take Clozaril if you have any of the following medical conditions:
- Any disease of the blood which causes a reduced number of red blood cells or platelets;
- Symptoms of active liver disease such as jaundice (yellow colour to the skin and eyes, feeling sick, loss of appetite) or any other severe liver disease;
- Severe kidney disease;
- Myocarditis (an inflammation of the heart muscle) or any other heart problems;
- Uncontrolled epilepsy (i.e. you still have some seizures);
- Paralytic ileus, a condition in which the small bowel does not work properly;
- Severe constipation, obstruction of the bowel, or any other condition which has affected your large bowel;
- Bone marrow disease;
- Problems with alcohol or drug abuse.
Clozaril must not be given to anyone who is unconscious or in a coma, or who has an acute mental illness caused by alcohol or drugs.
Do not take Clozaril after the expiry date printed on the pack or if the packaging is torn or shows signs of tampering. In that case, return it to your pharmacist.
If you are not sure whether you should start taking Clozaril, talk to your doctor or pharmacist.
Before you start to take it
Tell your doctor if you have ever had any of the following medical conditions:
- Any form of heart disease or a family history of heart disease;
- Family history of an abnormal conduction in the heart called “prolongation of the QT interval”;
- Neuroleptic malignant syndrome, a reaction to some medicines with a sudden increase in body temperature, sweating, fast heartbeat, muscle stiffness and fluctuating blood pressure, which may lead to coma;
- Tardive dyskinesia, a reaction to some medicines with uncontrolled movements of the tongue, face, mouth or jaw (such as puffing of the cheeks, puckering of the mouth or chewing movements);
- Problems with your liver or kidneys;
- Glaucoma, a condition in which there is usually a build-up of fluid in the eye;
- Enlargement of the prostate or prostate problems;
- Epilepsy that is under control (i.e. you no longer have seizures);
- Diabetes or a family history of diabetes;
- Chronic constipation;
- Dementia, a condition in which there is a decline in all areas of mental ability;
- Any other serious medical condition.
Tell your doctor if you are pregnant or intend to become pregnant. Experience with Clozaril in pregnancy is very limited. If you need to take this medicine during pregnancy, your doctor will discuss with you the benefits and risks of taking it.
Newborn babies of mothers taking antipsychotic drugs during the third trimester of pregnancy may have increased risk of developing stiff limbs, trembling, agitation, muscle stiffness, muscle flaccidity, drowsiness, short and shallow breathing, and feeding disorders following delivery. In some cases these symptoms may be self-limiting, in other cases, babies may require intensive care unit support or hospitalisation.
Tell your doctor if you are breastfeeding or plan to breastfeed. You should not breastfeed during Clozaril treatment. This medicine may pass into breast milk and may affect your baby.
Tell your doctor if you smoke and how much coffee you drink. Sudden changes in your usual smoking or coffee drinking habits can also change the effects of Clozaril.
Tell your doctor if you will be in a hot environment or you do a lot of vigorous exercises. Clozaril may make you sweat less, causing your body to overheat.
Tell your doctor if you are lactose intolerant. This medicine contains lactose.
Tell your doctor if you have allergies to other medicines or to any other substances such as foods, preservatives or dyes.
If you have not told your doctor about any of the above, tell them before you start taking Clozaril.
Taking other medicines
Tell your doctor or pharmacist if you are taking any other medicines, including any that you buy without a prescription from a pharmacy, supermarket or health food shop.
Some medicines and Clozaril may interfere with each other. These include:
- Medicines that decrease the number of blood cells produced by your body;
- Other antipsychotic medicines used to treat mental illnesses;
- Medicines used to control depression or mood swings;
- Benzodiazepines and other medicines used to treat anxiety or to help you sleep;
- Medicines used to control epilepsy, including phenytoin, carbamazepine and valproic acid;
- Warfarin, a medicine used to prevent blood clots;
- Strong painkillers such as morphine;
- St John’s wort, an ingredient in many medicines that you can buy without a prescription from a pharmacy, health food shop or supermarket;
- Antihistamines, medicines used for colds or allergies such as hay fever;
- Anticholinergic medicines, which are used to relieve stomach cramps, spasms and travel sickness;
- Medicines used to treat Parkinson’s disease;
- Medicines used to treat high blood pressure;
- Digoxin, a medicine used to treat heart problems;
- Medicines used to treat a fast or irregular heartbeat;
- Some medicines used to treat stomach ulcers, including cimetidine, omeprazole, pantoprazole and lansoprazole;
- Some antibiotic medicines, including erythromycin, clarithromycin, azithromycin, ciprofloxacin, norfloxacin and rifampicin;
- Some medicines used to treat fungal or viral infections;
- Nicotine in medicines used to help you quit smoking, such as nicotine patches or chewing gum;
- Atropine, a medicine which may be used in some eye drops or cough and cold preparations;
- Adrenaline, a drug used in emergency situations;
- Birth-control tablets.
These medicines may be affected by Clozaril or they may affect how well Clozaril works. You may need to take different amounts of your medicines or you may need to take different medicines.
Your doctor and pharmacist have more information on medicines to be careful with or avoid while taking Clozaril.
How to take Clozaril
Follow all directions given to you by your doctor and pharmacist carefully. They may differ from the information contained here.
If you do not understand the instructions on the label, ask your doctor or pharmacist for help.
How much to take
The usual starting dose is half of a 25 mg tablet once or twice on the first day. The dose is usually increased to one 25 mg tablet once or twice on the second day. After that, the dose can be slowly increased until the desired effect is achieved. Usually, the total amount of Clozaril needed each day will be between 200 mg and 450 mg but some people will need higher doses.
Once the maximum benefit is reached, the dose can often be decreased to between 150 mg and 300 mg each day.
If you have heart, kidney or liver disease, are prone to seizures (fits) or are elderly, your doctor may start you on a lower dose and increase it more gradually to prevent unwanted side effects.
How to take it
Swallow the tablets with a full glass of water or other liquid. Take the tablets at about the same time each day.
Taking your tablets at the same time each day will have the best effect. It will also help you remember when to take them.
The total daily amount of Clozaril is usually divided into 2 doses (morning and bedtime). But, if your total dose is 200 mg or less, your doctor may allow you to take the whole amount at once, usually in the evening.
If you forget to take it
If it is almost time for your next dose (within 4 hours), skip the dose you missed and take the next dose when you are meant to.
Otherwise, take it as soon as you remember, and then go back to taking it as you would normally.
Do not take a double dose to make up for the one that you missed. This may increase the chance of you getting an unwanted side effect.
If you have forgotten to take Clozaril for more than 2 days, do not start taking it again before you contact your doctor. To prevent unwanted side effects, your doctor will probably want you to restart Clozaril at a low dose and increase it gradually back to the amount you were taking before.
If you are not sure what to do, ask your doctor or pharmacist. If you have trouble remembering when to take your medicine, ask your pharmacist for some hints.
How long to take it
Continue taking the tablets for as long as your doctor tells you.
Your doctor will check your progress to make sure the medicine is working and will discuss with you how long your treatment should continue.
If you take too much (overdose)
Immediately telephone your doctor or the Poisons Information Centre (telephone 13 11 26), or go to Accident and Emergency at your nearest hospital if you think that you or anyone else may have taken too much Clozaril. Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.
The most common symptoms of an overdose include lightheadedness due to low blood pressure, too much saliva, difficulty breathing, fast or irregular heartbeat, drowsiness, confusion and unconsciousness.
While you are taking Clozaril
Things you must do
Continue taking Clozaril as long as your doctor tells you. If you have questions about how long to take Clozaril, talk to your doctor or your pharmacist.
You must have strict and regular blood tests while taking Clozaril. Clozaril can cause agranulocytosis. This is a condition where the number of white blood cells in your body is reduced. White blood cells are needed to fight infection. There is no way of knowing who is at risk of developing agranulocytosis. Deaths have occurred in severe cases of agranulocytosis. However, with regular blood tests, the problem can be detected early. If Clozaril is stopped as soon as possible, the white blood cell numbers should return to normal.
You must have a blood test at least once a week for the first 18 weeks after starting Clozaril. This is the time when the risk of agranulocytosis is greatest. These tests can tell the doctor whether the white blood cell count is dropping.
After 18 weeks, you must have a blood test at least every 4 weeks for as long as you are taking Clozaril and for a month after stopping the medicine. There are some situations where you may need to have blood tests more often (e.g. twice a week). Your doctor will explain this to you.
If the number of white blood cells falls below a critical level, Clozaril will be stopped immediately and you must never take Clozaril again.
If you suffer from a high level of sugar in the blood (diabetes) your doctor may regularly check your level of sugar in the blood.
Watch for important side effects. If you develop a fast or irregular heartbeat that is present even when you are resting, accompanied by rapid breathing, shortness of breath, swelling of the feet or legs, dizziness or lightheadedness, or chest pain, contact your doctor immediately as these may cause death. These symptoms could be signs of myocarditis, an inflammation of the heart muscle, or another heart condition. Your doctor may want to refer you to a cardiologist for further tests.
If you develop a fever, contact your doctor immediately. Some patients develop a fever in the first few weeks of taking Clozaril. You must be checked carefully to make sure that you do not have agranulocytosis, myocarditis or neuroleptic malignant syndrome, a reaction to some medicines with a sudden increase in body temperature.
If you develop a sore throat, mouth ulcers, flu-like symptoms or any other sign of a cold or infection, contact your doctor immediately. Your doctor will check your blood to decide if your symptoms are an early sign of agranulocytosis. Flu-like symptoms may also be a sign of myocarditis.
If you notice any uncontrolled movements of the tongue, face, mouth or jaw, such as puffing of the cheeks, puckering of the mouth or chewing movements, tell your doctor immediately. These are symptoms of a very rare condition called tardive dyskinesia which may develop in people taking antipsychotic medicines. This condition is more likely to happen during long-term treatment, especially in elderly women. In very rare cases, it may be permanent. However, if detected early, these symptoms are usually reversible.
If you suffer from abdominal pain and constipation tell your doctor immediately. These may be a sign of abnormal dilation of the large intestines which may lead to death. If you develop abdominal pain it could be a sign of a breakdown of part of the intestine due to reduced blood supply which may lead to death.
Make sure you use a contraceptive to prevent pregnancy during treatment with Clozaril. Some women taking some antipsychotic medications have irregular or no periods. If you are female and you have been affected in this way, your periods may return when your medication is changed to Clozaril.
If you become pregnant while taking this medicine, tell your doctor immediately. Newborn babies of mothers taking antipsychotic drugs during the third trimester of pregnancy may have increased risk of developing stiff limbs, trembling, agitation, muscle stiffness, muscle flaccidity, drowsiness, short and shallow breathing, and feeding disorders following delivery. In some cases these symptoms may be self-limiting, in other cases, babies may require intensive care unit support or hospitalisation. Your doctor can discuss with you the risks of taking it while you are pregnant.
If you are about to be started on any new medicine, remind your doctor and pharmacist that you are taking Clozaril.
If you plan to have surgery, tell your doctor that you are taking Clozaril.
Tell any other doctor, dentist or pharmacist, who treats you that you are taking Clozaril.
Things you must not do
Do not stop taking Clozaril or lower the dosage, even if you are feeling better, without checking with your doctor.
If you stop taking Clozaril suddenly, your condition may worsen or you may have unwanted side effects such as excessive sweating, headache, nausea (feeling sick), vomiting and diarrhoea. If this medicine is stopped for any reason, your doctor will reduce the dose gradually, over a one to two week period, to avoid side effects, before stopping the medicine completely.
Do not take Clozaril to treat any other complaints unless your doctor tells you to.
Do not give this medicine to anyone else, even if their condition seems similar to yours.
Things to be careful of
Sudden unexplained death and heart attacks that may lead to death have been reported with Clozaril.
Be careful driving or operating machinery until you know how Clozaril affects you. As with other antipsychotic medicines, Clozaril may cause tiredness, drowsiness, dizziness, light-headedness, fainting or seizures (fits) in some people, especially at the start of treatment. Seizures, drowsiness, fainting, muscle weakness may lead to falls. Make sure you know how you react to Clozaril before you drive a car, operate machinery or do anything else that could be dangerous.
You should not drink alcohol while you are taking Clozaril. Clozaril may enhance the effects of alcohol.
Be careful when taking pain relievers, sleeping tablets or antihistamines (medicines for colds or allergies such as hay fever) while you are taking Clozaril. Clozaril can increase the drowsiness caused by medicines that affect your nervous system.
Clozaril may cause an alteration in blood lipids. It may also cause weight gain. Your doctor may monitor your weight and blood lipid levels.
Clozaril can cause sleepiness, and remaining in bed for prolonged duration in combination with weight gain may lead to the formation of blood clots in some patients.
If Clozaril makes you feel lightheaded, dizzy or faint, be careful when getting up from a sitting or lying position. Clozaril may lower your blood pressure, especially at the start of treatment. These symptoms can usually be prevented by getting up slowly and flexing leg muscles and toes to get the blood flowing. When getting out of bed, dangle your legs over the side for a minute or two before standing up.
Make sure you keep cool in hot weather and keep warm in cool weather. As with other antipsychotic medicines, Clozaril may affect the way your body reacts to temperature changes. It may prevent sweating, even during heat waves. You may feel dizzy or faint if you are too hot.
To stay cool in hot weather, try to do the following:
- Wear light clothing;
- Spend time in air-conditioned environments (or keep windows open and use electric fans);
- Drink plenty of water;
- Take cool baths or showers and avoid hot baths and saunas;
- Try to restrict exercise or heavy work to cool parts of the day.
Inform your doctor if you stop smoking or change the number of caffeine-containing drinks that you have in one day. These changes can affect the levels of this medicine in your blood.
After using Clozaril
- Keep your tablets in the original container until it is time to take them;
- Store the tablets in a cool dry place;
- Do not store Clozaril or any other medicine in the bathroom or near a sink;
- Do not leave it in the car or on window sills.
Heat and dampness can destroy some medicines. Clozaril will keep well if it is cool and dry.
Keep the medicine where children cannot reach it. A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.
If your doctor tells you to stop taking Clozaril or it has passed its expiry date, ask your pharmacist what to do with any medicine you have left over.
Remember that you must still have your blood tested for a month after stopping this medicine.
Schedule of Clozaril
Clozaril is a Schedule 4 (prescription only) medicine.
Side effects of Clozaril
Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking Clozaril, even if you do not think it is connected with the medicine.
All medicines can have side effects. Sometimes they are serious, but most of the time they are not. You may need medical treatment if you get some of the side effects. Some of the side effects of Clozaril can be relieved by changing the dose.
If you are over 65 years old, you should be especially careful while taking this medicine. Report any side effects promptly to your doctor. You may be more likely to get some of the side effects of Clozaril, such as rapid heartbeat, dizziness or lightheadedness due to low blood pressure, constipation and difficulty urinating.
Do not be alarmed by this list of possible side effects. You may not experience any of them. Ask your doctor or pharmacist to answer any questions you may have.
Tell your doctor if you notice any of the following and they worry you:
- Tiredness, drowsiness;
- Dizziness or lightheadedness when standing up;
- Constipation (if it seems to be getting worse, check with your doctor immediately);
- Agitation, confusion, disorientation, vivid dreams;
- Dry mouth;
- Blurred vision, difficulty in reading;
- Increased or decreased sweating;
- Too much saliva;
- Nausea (feeling sick), vomiting;
- Stomach discomfort, especially after a meal;
- Difficulty in swallowing;
- Weight gain, especially excessive weight gain;
- Changes in sexual function;
- Painful menstrual periods;
- Repetitive and ritualised behaviour (obsessive-compulsive symptoms);
- Abdominal pain;
- Problems in passing or holding urine;
- Dark urine;
- Excessive urination;
- Nocturnal bedwetting;
- Stuttering in speech;
- Skin reactions or change in skin colour;
- Stuffy nose;
- Obsessive thoughts;
- Swelling of the glands in the cheeks;
- Rash, purplish-red spots, fever or itching;
- Diarrhoea, abdominal pain and fever;
- “Butterfly” rash, joint pain, muscle pain, fever and fatigue;
- Sudden, uncontrollable increase in blood pressure;
- Uncontrolled bending of the body to one side;
- For males, dry orgasm (retrograde ejaculation) where very little or no semen is ejaculated as it enters the bladder instead. Urine will appear cloudy after an orgasm;
- A strong urge to move the legs (restless legs syndrome) with an unpleasant feeling in the legs.
Tell your doctor immediately or go to Accident and Emergency at your nearest hospital if you notice any of the following:
- Fainting or loss of consciousness;
- Falls due to seizure, drowsiness, fainting, muscle weakness;
- Crushing chest pain or chest pain;
- Fever, sore throat, mouth ulcers, “flu-like” symptoms (chills, aching joints, swollen glands, lack of energy) or any other signs of infection;
- A fast or irregular heartbeat that is present even when you are resting, accompanied by rapid breathing, shortness of breath, swelling of the feet or legs, dizziness or lightheadedness, or chest pain;
- Sudden signs of allergy such as rash, itching or hives on the skin; swelling of the face, lips, tongue or other parts of the body; wheezing or troubled breathing;
- Symptoms of neuroleptic malignant syndrome, with a sudden increase in body temperature, sweating, fast heartbeat, muscle stiffness and fluctuating blood pressure, which may lead to coma;
- Seizures (fits);
- Pain in the stomach, often accompanied by nausea and vomiting;
- Severe or prolonged constipation, which may be accompanied by abdominal pain and bloating;
- Signs of loss of blood sugar control (diabetes) such as excessive thirst, drinking or eating large amounts, weakness, passing large amounts of urine, dry mouth and skin, as Clozaril may cause or worsen diabetes;
- Spontaneous bleeding or bruising more easily than normal;
- Signs that blood clots may have formed, such as sudden severe headache, sudden loss of coordination, blurred vision or sudden loss of vision, slurred speech, numbness in an arm or leg;
- Yellowing of the skin and/or eyes, sometimes accompanied by feeling sick and loss of appetite;
- Difficulty in passing urine (water) or blood in the urine;
- Loss of bladder control;
- Muscle stiffness, muscle weakness, muscle spasms, or muscle pain;
- Muscle spasms, fever, red-brown urine;
- Rigidity or stiffness in the arms and legs, shaking or tremor, feeling unable to sit still;
- Abnormal movements, inability to initiate movement, inability to remain motionless, inner feeling restlessness, stiff limbs, trembling hands;
- Symptoms of tardive dyskinesia (uncontrolled involuntary purposeful movements of the tongue, face, mouth or jaw such as puffing of the cheeks, puckering of the mouth, chewing movements, grimacing, lip smacking, rapid eye blinking);
- Persistent painful erection or prolonged erection;
- Signs of respiratory tract infection or pneumonia such as fever, coughing, difficulty breathing, wheezing;
- Signs of sepsis such as shivering, fever, rapid breathing and heart rate, a change in your mental states such as confusion or disorientation;
- Chest pain, cough, hiccups, rapid breathing;
- Varying degrees of pain in the chest and abdomen;
- Pauses in breathing or periods of shallow breathing during sleep.
The above are serious side effects that need medical attention.
Tell your doctor if you notice anything else that is making you feel unwell. Other side effects not listed here may happen in some people.
For further information talk to your doctor.