• you are allergic to any ingredient in Clozaril
• you have bone marrow problems, other blood cell problems, or a history of blood problems caused by Clozaril
• you have uncontrolled seizures (eg, epilepsy) or loss of bowel muscle movement (paralytic ileus)
• you have severe drowsiness
• you are taking other medicines that may cause blood problems. Ask your doctor if you are unsure if any of your medicines may cause blood problems.

Contact your doctor or health care provider right away if any of these apply to you.

Some medical conditions may interact with Clozaril. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have a history of blood clots, blood problems, high blood cholesterol levels, heart problems, or lung or breathing problems
• if you have a history of an enlarged prostate; prolonged, painful erections; liver or kidney problems; seizures (eg, epilepsy); glaucoma; stomach or bowel problems; or dementia
• if you have poor health, diabetes, or a family member with diabetes, or you are very overweight
• if you have decreased activity of enzymes that metabolize certain medicines.

Some medicines may interact with Clozaril. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Benzodiazepines (eg, lorazepam) or other medicines for mental or mood problems because the risk of heart or breathing problems may be increased
• Cimetidine, erythromycin, quinolone antibiotics (eg, ciprofloxacin), risperidone, or selective serotonin reuptake inhibitors (SSRIs) (eg, fluoxetine) because they may increase the risk of Clozaril's side effects
• Barbiturates (eg, phenobarbital), hydantoins (eg, phenytoin), nicotine, or rifampin because they may decrease Clozaril's effectiveness
• Antiarrhythmics (eg, propafenone, quinidine), anticholinergics (eg, benztropine), carbamazepine, debrisoquin, dextromethorphan, medicines for depression or high blood pressure, phenothiazines (eg, chlorpromazine), or tricyclic antidepressants (eg, amitriptyline) because the risk of their side effects may be increased by Clozaril.

This may not be a complete list of all interactions that may occur. Ask your health care provider if Clozaril may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

Important safety information:

• Clozaril may cause drowsiness, dizziness, or lightheadedness. These effects may be worse if you take it with alcohol or certain medicines. Use Clozaril with caution. Do not drive or perform other possible unsafe tasks until you know how you react to it.
• Do not use alcohol or medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you taking Clozaril. It may increase their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
• Clozaril may cause dizziness, lightheadedness, or fainting; alcohol, hot weather, exercise, or fever may increase these effects. To prevent them, sit up or stand slowly, especially in the morning. Sit or lie down at the first sign of any of these effects.
• Clozaril may lower the ability of your body to fight infection. Avoid contact with people who have colds or infections. Tell your doctor right away if you notice any signs of infection like fever, sore throat, rash, chills, mouth or nose sores, or unusual tiredness or weakness.
• Women and patients of Jewish background may be at greater risk of developing blood problems with Clozaril.
• If you have a history of seizures, you may suddenly lose conscious while you are taking Clozaril. Avoid activities in which loss of conscious could be dangerous to you or others (eg, driving, swimming, climbing, operating machinery).
• Clozaril may raise your blood sugar. High blood sugar may make you feel confused, drowsy, or thirsty. It can also make you flush, breathe faster, or have a fruit-like breath odor. If these symptoms occur, tell your doctor right away.
• Avoid food and drink high in caffeine, like coffee, tea, cocoa, cola, and chocolate.
• Tell your doctor or dentist that you take Clozaril. It could have an effect on the medical or dental care, emergency care, or surgery you may receive.
• Neuroleptic malignant syndrome (NMS) is a possibly fatal syndrome that can be caused by Clozaril. Symptoms may include fever, stiff muscles, confusion, abnormal thinking, fast or irregular heartbeat, and sweating. Contact your doctor at once if you have any of these symptoms.
• Some patients who take Clozaril may develop muscle movements that they cannot control. This is more likely to happen in elderly patients, especially women. The chance that this will happen or that it will become permanent is greater in those who take Clozaril in high doses or for a long time. Muscle problems may also occur after short-term treatment with low doses. Tell your doctor at once if you have muscle problems with your tongue, face, mouth, jaw (eg, tongue sticking out, puffing of cheeks, mouth puckering, chewing movements), arms, or legs while taking Clozaril.
• Lab tests, including complete blood cell counts and heart function tests, may be performed to monitor your progress or check for side effects. Be sure to keep all doctor and lab appointments.
• Use Clozaril with caution in the elderly; they may be more sensitive to its effects, especially blood problems, dizziness (especially upon standing), fast heartbeat, urinary problems, and constipation.
• Clozaril should be used with extreme caution in children; safety and effectiveness in children have not been determined.
• Pregnancy and breast-feeding: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Clozaril while you are pregnant. It is not known if Clozaril is found in breast milk. Do not breastfeed while taking Clozaril.

Check with your doctor if any of these most common side effects persist or become bothersome:

Constipation; dizziness; drowsiness; dry mouth; headache; heartburn; increased sweating or saliva production; lightheadedness when you stand up; nausea; strange dreams; trouble sleeping; weight gain.

Seek medical attention right away if any of these severe side effects occur:

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); agitation; calf pain or tenderness; chest pain; confusion; dark urine; decreased coordination; fainting; fast or irregular heartbeat; fever, chills, or sore throat; increased hunger, thirst, or urination; infection; involuntary movements of the tongue, face, mouth, or jaw (eg, tongue sticking out, puffing of cheeks, mouth puckering, chewing movements); loss of appetite; numbness of an arm or leg; rapid breathing; restlessness; seizures; severe headache, dizziness, or vomiting; severe or persistent nausea or constipation; severe stomach pain; shortness of breath; stiff muscles; sudden, unusual weight gain; swelling of the hands, ankles, or feet; tremor; trouble swallowing; uncontrolled muscle movements; unusual mental or mood changes; unusual tiredness or weakness; vision changes; vomiting; yellowing of the skin or eyes.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.