pronounced as (kloe' za peen)

Brand Name(s): Clozaril®, FazaClo® ODT, Versacloz®, also available generically

Why is this medicine prescribed?

Clozapine is used to treat the symptoms of schizophrenia (a mental illness that causes disturbed or unusual thinking, loss of interest in life, and strong or inappropriate emotions) in people who have not been helped by other medications or who have tried to kill themselves and are likely to try to kill or harm themselves again. Clozapine is in a class of medications called atypical antipsychotics. It works by changing the activity of certain natural substances in the brain.

Are there other uses for this medicine?

This medication should not be prescribed for other uses; ask your doctor or pharmacist for more information.

How should this medicine be used?

Clozapine comes as a tablet, an orally disintegrating tablet (tablet that dissolves quickly in the mouth), and an oral suspension (liquid) to take by mouth. It is usually taken once or twice daily. Take clozapine at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take clozapine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Do not try to push the orally disintegrating tablet through the foil packaging. Instead, use dry hands to peel back the foil. Immediately take out the tablet and place it on your tongue. The tablet will quickly dissolve and can be swallowed with saliva. No water is needed to swallow disintegrating tablets.

To measure clozapine oral suspension, follow these steps:

  1. Make sure the cap is tight on the oral suspension container by turning the cap clockwise (to the right). Shake the bottle up and down for 10 seconds before use.
  2. Remove the bottle cap by pushing down on the cap, then turn it counterclockwise (to the left). The first time you open a new bottle, push the adaptor into the bottle until the top of the adaptor is lined up with the top of the bottle.
  3. If your dose is 1 mL or less, use the smaller (1 mL) oral syringe. If your dose is more than 1 mL, use the larger (9 mL) oral syringe.
  4. Fill the oral syringe with by air by drawing back the plunger. Then insert the open tip of the oral syringe into the adaptor. Push all the air from the oral syringe into the bottle by pushing down on the plunger.
  5. While holding the oral syringe in place, carefully turn the bottle upside down. Draw some of the medication out of the bottle into the oral syringe by pulling back on the plunger. Be careful not to pull the plunger all the way out.
  6. You will see a small amount of air near the end of the plunger in the oral syringe. Push on the plunger so the medication goes back into the bottle and the air disappears. Pull back on the plunger to draw your correct medication dose into the oral syringe.
  7. While still holding the oral syringe in the bottle, carefully turn the bottle upwards so the syringe is on top. Remove the oral syringe from the bottle neck adaptor without pushing on the plunger. Take the medication right after you draw it into the oral syringe. Do not prepare a dose and store it in the syringe for later use.
  8. Place the open tip of the oral syringe into one side of your mouth. Tightly close your lips around the oral syringe and push on the plunger slowly as the liquid goes into your mouth. Swallow the medication slowly as it goes into your mouth.
  9. Leave the adaptor in the bottle. Place the cap back on the bottle and turn it clockwise (to the right) to tighten it.
  10. Rinse the oral syringe with warm tap water after each use. Fill a cup with water and place the tip of the oral syringe into the water in the cup. Pull back on the plunger and draw the water into the oral syringe. Push on the plunger to squirt the water into a sink or a separate container until the oral syringe is clean. Allow the oral syringe air dry and dispose of any leftover rinse water.

Clozapine controls schizophrenia but does not cure it. It may take several weeks or longer before you feel the full benefit of clozapine. Continue to take clozapine even if you feel well. Do not stop taking clozapine without talking to your doctor. Your doctor will probably want to decrease your dose gradually.

What special precautions should I follow?

Before taking clozapine,

  • tell your doctor and pharmacist if you are allergic to clozapine, any other medications, or any of the ingredients in clozapine tablets. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention those listed in the IMPORTANT WARNING section and any of the following: antihistamines such as diphenhydramine (Benadryl); antibiotics such as ciprofloxacin (Cipro) and erythromycin (E.E.S., E-Mycin, others); benztropine (Cogentin); cimetidine (Tagamet); bupropion (Aplenzin, Wellbutrin, Zyban, in Contrave); cyclobenzaprine (Amrix); escitalopram (Lexapro); medications for anxiety, high blood pressure, mental illness, motion sickness, or nausea; medications for irregular heartbeat such as encainide, flecainide, propafenone (Rythmol), and quinidine (in Nuedexta); oral contraceptives; medications for seizures such as carbamazepine (Equetro, Tegretol, Teril, others) or phenytoin (Dilantin, Phenytek); rifampin (Rifadin, Rimactane, in Rifamate, in Rifater); sedatives; selective serotonin reuptake inhibitors (SSRIs) such as duloxetine (Cymbalta), fluoxetine (Prozac, Sarafem, Selfemra, others), fluvoxamine (Luvox), paroxetine (Brisdelle, Paxil, Pexeva), and sertraline (Zoloft); sleeping pills; terbinafine (Lamisil); and tranquilizers. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor what herbal products you are taking, especially St. John's wort.
  • in addition to the condition listed in the IMPORTANT WARNING section, tell your doctor if you or anyone in your family has ever had a prolonged QT interval (a rare heart problem that may cause irregular heartbeat, fainting, or sudden death) or diabetes. Tell your doctor if you have constipation, nausea, vomiting, or stomach pain or distension; or if you have or have ever had problems with your urinary system or prostate (a male reproductive gland); dyslipidemia (high cholesterol levels); paralytic ileus (condition in which food cannot move through the intestine); glaucoma; high or low blood pressure; trouble keeping your balance; or heart, kidney, lung, or liver disease. Also tell your doctor if you have ever had to stop taking a medication for mental illness because of severe side effects.
  • tell your doctor if you are pregnant, especially if you are in the last few months of your pregnancy, or if you plan to become pregnant or are breastfeeding. If you become pregnant while taking clozapine, call your doctor. Clozapine may cause problems in newborns following delivery if it is taken during the last months of pregnancy.
  • you should know that you may experience hyperglycemia (increases in your blood sugar) while you are taking this medication, even if you do not already have diabetes. If you have schizophrenia, you are more likely to develop diabetes than people who do not have schizophrenia, and taking clozapine or similar medications may increase this risk. Tell your doctor immediately if you have any of the following symptoms while you are taking clozapine: extreme thirst, frequent urination, extreme hunger, blurred vision, or weakness. It is very important to call your doctor as soon as you have any of these symptoms, because high blood sugar can cause a serious condition called ketoacidosis. Ketoacidosis may become life-threatening if it is not treated at an early stage. Symptoms of ketoacidosis include: dry mouth, nausea and vomiting, shortness of breath, breath that smells fruity, and decreased consciousness.
  • if you have phenylketonuria (PKU, an inherited condition in which a special diet must be followed to prevent damage to your brain that can cause severe intellectual disability), you should know that the orally disintegrating tablets contain aspartame that forms phenylalanine.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking clozapine.
  • you should know that alcohol can add to the drowsiness caused by this medication.
  • tell your doctor if you use tobacco products. Cigarette smoking may decrease the effectiveness of this medication.

What special dietary instructions should I follow?

Talk to your doctor about drinking caffeinated beverages while taking this medicine.

What should I do if I forget to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What should I do in case of overdose?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at . If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

  • dizziness
  • fainting
  • slow breathing
  • change in heartbeat
  • loss of consciousness

What side effects can this medicine cause?

Clozapine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • drowsiness
  • dizziness, feeling unsteady, or having trouble keeping your balance
  • increased salivation
  • dry mouth
  • restlessness
  • headache

Some side effects can be serious. If you experience any of the following symptoms or those listed in the IMPORTANT WARNINGS or SPECIAL PRECAUTIONS sections, call your doctor immediately:

  • constipation; nausea; stomach swelling or pain; or vomiting
  • shaking hands that you cannot control
  • fainting
  • falling
  • difficulty urinating or loss of bladder control
  • confusion
  • changes in vision
  • shakiness
  • severe muscle stiffness
  • sweating
  • changes in behavior
  • unusual bleeding or bruising
  • loss of appetite
  • upset stomach
  • yellowing of the skin or eyes
  • pain in upper right part of the stomach
  • lack of energy

Clozapine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( ) or by phone (1-800-332-1088).

What should I know about storage and disposal of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light and excess heat and moisture (not in the bathroom). Do not refrigerate or freeze the oral suspension.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach.

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website ( ) for more information if you do not have access to a take-back program.

What other information should I know?

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to clozapine.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

subscribe section background