Clozapine

Pronunciation

Generic Name: clozapine (KLOE-za-peen)
Brand Name: Clozaril

Clozapine may cause a serious blood disorder (agranulocytosis). This blood disorder can lead to serious infection and death. Lab tests will be performed before use and while you use clozapine to check for this side effect. Call your doctor right away if you have fever, chills, sore throat, or unusual tiredness or weakness. Because of the risk of agranulocytosis, you can only get clozapine through a special program. Discuss any questions or concerns with your doctor.

Low blood pressure, slow heartbeat, fainting, and heart attack have occurred with the use of clozapine. The risk is highest when the dose is being increased, especially if it is increased too fast. These reactions can occur with any dose of clozapine. Take clozapine as directed by your doctor. Tell your doctor if you have brain or heart problems (eg, blood vessel problems), if you are dehydrated, or if you take medicine for blood pressure.

Seizures have occurred with the use of clozapine. The risk of seizures may be greater with higher doses, or if you have a history of seizures, if you take medicines that increase the risk of seizures, or if you abuse alcohol. Do not perform activities in which a sudden loss of consciousness could cause harm to yourself or others (eg, driving, swimming).

Serious and sometimes fatal heart problems have occurred with the use of clozapine. Call your doctor right away if you have chest pain, fast or irregular heartbeat, shortness of breath, fever, flu-like symptoms, dizziness, or fainting.

Clozapine may increase the risk of death when used to treat mental problems caused by dementia in elderly patients. Most of the deaths were linked to heart problems or infection. Clozapine is not approved to treat mental problems caused by dementia.


Clozapine is used for:

Managing schizophrenia in patients who do not respond to other medicines. It is used to decrease the risk of suicidal behavior in certain patients. It may also be used for other conditions as determined by your doctor.

Clozapine is an atypical antipsychotic. It may work by affecting certain chemicals in the brain, which has an effect on thinking and behavior.

Do NOT use clozapine if:

  • you are allergic to any ingredient in clozapine
  • you have bone marrow problems (eg, myeloproliferative disorders) or certain blood problems
  • you have a history of blood or heart problems caused by clozapine
  • you have uncontrolled seizures (eg, epilepsy) or bowel blockage (paralytic ileus)
  • you have severe drowsiness
  • you are taking metoclopramide
  • you are taking other medicines that may decrease bone marrow function or cause certain blood problems. Ask your doctor if you are unsure if any of your medicines may cause these problems

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

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Before using clozapine:

Some medical conditions may interact with clozapine. 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, blood vessel problems, heart problems or a heart attack, high blood pressure, a stroke, lung or breathing problems, or high blood cholesterol levels
  • if you or a member of your family have had a certain type of irregular heartbeat (QT prolongation, long QT syndrome)
  • if you have low blood potassium or magnesium levels, or if you are at risk for low blood potassium or magnesium levels
  • if you have a history of blood problems caused by another medicine
  • if you have a history of an enlarged prostate; prolonged, painful erections; liver or kidney problems; seizures (eg, epilepsy); neuroleptic malignant syndrome (NMS); glaucoma; stomach or bowel problems; or dementia
  • if you have diarrhea, poor health, severe loss of weight or muscle caused by another disease (eg, cancer), diabetes, or a family member with diabetes, or if you are very overweight
  • if you have decreased metabolism of certain medicines
  • if you smoke, are exposed to tobacco smoke, or you regularly consume food and drinks high in caffeine (eg, coffee, tea, soda)
  • if you are scheduled for surgery or to receive anesthesia

Some MEDICINES MAY INTERACT with clozapine. 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
  • Antiarrhythmics (eg, amiodarone, propafenone, flecainide, quinidine), diuretics (eg, furosemide, hydrochlorothiazide), dolasetron, droperidol, iloperidone, macrolide antibiotics (eg, erythromycin), mefloquine, methadone, ondansetron, pentamidine, phenothiazines (eg, chlorpromazine, thioridazine), pimozide, quinolone antibiotics (eg, ciprofloxacin), tacrolimus, ziprasidone or any other medicine that may increase the risk of a certain type of irregular heartbeat (prolonged QT interval). Check with your doctor or pharmacist if you are unsure if any of your medicines may increase the risk of this type of irregular heartbeat
  • Cimetidine, lithium, metoclopramide, risperidone, selective serotonin reuptake inhibitors (SSRIs) (eg, citalopram, fluoxetine, fluvoxamine), or tramadol because they may increase the risk of clozapine's side effects
  • Barbiturates (eg, phenobarbital), hydantoins (eg, phenytoin), or rifamycins (eg, rifampin) because they may decrease clozapine's effectiveness
  • Anticholinergics (eg, benztropine), carbamazepine, debrisoquin, dextromethorphan, medicines for depression or high blood pressure, or tricyclic antidepressants (eg, amitriptyline) because the risk of their side effects may be increased by clozapine

This may not be a complete list of all interactions that may occur. Ask your health care provider if clozapine 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.

How to use clozapine:

Use clozapine as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Clozapine may be taken with or without food. If stomach upset occurs, take with food to reduce stomach irritation.
  • Continue to take clozapine even if you feel well. Do not miss any doses.
  • Taking clozapine at the same time each day will help you to remember to take it.
  • Do not suddenly stop taking clozapine. You may have an increased risk of side effects. If you need to stop clozapine or add a new medicine, your doctor will gradually lower your dose.
  • If you miss a dose of clozapine, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once. If you miss taking a dose of clozapine for more than 2 days, do not start taking it again. Contact your doctor right away for instructions.

Ask your health care provider any questions you may have about how to use clozapine.

Important safety information:

  • Clozapine may cause drowsiness, dizziness, or light-headedness. These effects may be worse if you take it with alcohol or certain medicines. Use clozapine with caution. Do not drive or perform other possibly unsafe tasks while you take clozapine.
  • Check with your doctor before you drink alcohol or use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are using clozapine; it may increase their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
  • Clozapine may cause dizziness, light-headedness, 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.
  • Do not take more than the recommended dose without checking with your doctor.
  • Clozapine 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 clozapine.
  • Seizures may occur in patients who take clozapine, which may cause you to suddenly lose consciousness. Avoid activities in which loss of consciousness could be dangerous to you or others (eg, driving, swimming, climbing, operating machinery).
  • Serious, and possibly fatal, heart problems have rarely occurred in patients who take clozapine. Symptoms may include chest pain; fast or irregular heartbeat; fever; rapid or difficult breathing; swelling of the hands, feet, or ankles; or unusual tiredness. Seek immediate medical attention if you experience any of these symptoms.
  • Clozapine 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 clozapine before you receive any medical or dental care, emergency care, or surgery.
  • Neuroleptic malignant syndrome (NMS) is a possibly fatal syndrome that can be caused by clozapine. 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 clozapine 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 clozapine 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 clozapine.
  • Lab tests, including complete blood cell counts and heart function, may be performed while you use clozapine and for at least 4 weeks after you stop taking it. These tests may be used to monitor your progress or check for side effects. Be sure to keep all doctor and lab appointments.
  • Use clozapine with caution in the ELDERLY; they may be more sensitive to its effects, especially blood problems, dizziness (especially when standing), fast heartbeat, urinary problems, and constipation.
  • Clozapine 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 taking clozapine while you are pregnant. Using clozapine during the third trimester may result in uncontrolled muscle movements or withdrawal symptoms in the newborn. Discuss any questions or concerns with your doctor. It is not known if clozapine is found in breast milk. Do not breast-feed while taking clozapine.

Possible side effects of clozapine:

All medicines may cause side effects, but many people have no, or minor, side effects. 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 standing 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; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); agitation; burning, numbness, or tingling; calf or leg pain or tenderness; chest pain; confusion; dark urine; decreased coordination; delirium; fainting; fast or difficult breathing; fast or irregular heartbeat; fever, chills, or sore throat; increased hunger, thirst, or urination; involuntary movements of the tongue, face, mouth, or jaw (eg, tongue sticking out, puffing of cheeks, mouth puckering, chewing movements); loss of appetite; new or worsening mental or mood changes; numbness of an arm or leg; obsessive-compulsive symptoms (eg, washing hands or checking doors continuously); persistent cough; restlessness; seizures; severe headache, dizziness, or vomiting; severe or persistent nausea or constipation; severe stomach pain; shortness of breath; sluggishness; stiff muscles; sudden, unusual weight gain; swelling of the hands, ankles, or feet; symptoms of a stroke (eg, one-sided weakness, slurred speech); tremor; trouble swallowing; trouble urinating; uncontrolled muscle movements; unusual bruising or bleeding; 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. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately. Symptoms may include coma; delirium; excessive salivation; fainting; fast or irregular heartbeat; seizures; severe or persistent dizziness or drowsiness; slow or shallow breathing.

Proper storage of clozapine:

Store clozapine at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep clozapine out of the reach of children and away from pets.

General information:

  • If you have any questions about clozapine, please talk with your doctor, pharmacist, or other health care provider.
  • Clozapine is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.
  • Check with your pharmacist about how to dispose of unused medicine.

This information should not be used to decide whether or not to take clozapine or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about clozapine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to clozapine. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using clozapine.

Issue Date: July 2, 2014
Database Edition 14.3.1.001
Copyright © 2014 Wolters Kluwer Health, Inc.

Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using this medicine.

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