Clozapine

Clozapine

(kloe’ za peen)

Other Names:Clozaril

Important Warning
Clozapine can cause a serious blood condition. Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests before starting treatment, once a week for the first 6 months, and at least once every other week therafter to check your response to clozapine.

Clozapine may cause seizures. Tell your doctor if you have or have ever had seizures. Do not drive a car, operate machinery, swim, or climb while taking clozapine, because if you suddenly lose consciousness you could harm yourself or others.

Clozapine may cause swelling of the heart muscle (myocarditis), a condition that can be dangerous. If you experience any of the following symptoms, call your doctor immediately: extreme tiredness; difficulty breathing or fast breathing; fever; chest pain; or fast, irregular, or pounding heartbeat.

Clozapine may cause low blood pressure and/or dizziness when you stand up, especially when you first start taking it. Tell your doctor if you are taking medications for anxiety such as diazepam (Valium), sleeping pills, or other medications for schizophrenia. Follow your doctor’s directions about starting to take a low dose of clozapine and gradually increasing the dose. If you stop taking clozapine for 2 days or longer, talk to your doctor about restarting clozapine on a low dose.

Why is this medication prescribed?
Clozapine is used to treat schizophrenia in patients where other medicine has not worked. Clozapine is in a class of medications called antipsychotics. It works by decreasing abnormal excitement in the brain.

How should this medicine be used?
Clozapine comes as a tablet to take by mouth. It usually is taken one to three times a 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.

The amount of clozapine you take may need to be adjusted, especially during the first few weeks. You will have weekly blood tests while taking clozapine and for 4 weeks after stopping it. Initially, you will receive only a 1-week supply of this medication at a time.

Continue to take clozapine even if you feel well. Do not stop taking clozapine without talking to your doctor, especially if you have taken large doses for a long time. Your doctor probably will want to decrease your dose gradually. This drug must be taken regularly for a few weeks before its full effect is felt.

What special precautions should I follow?
Before taking clozapine,

     
  • tell your doctor and pharmacist if you are allergic to clozapine or any other drugs.  
  • tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially those listed in the IMPORTANT WARNING section, anticoagulants (‘blood thinners’) such as warfarin (Coumadin), benztropine (Cogentin), carbamazepine (Tegretol), cimetidine (Tagamet), dicyclomine (Bentyl), erythromcyin (E.E.S., E-Mycin, others), medication for high blood pressure, phenytoin (Dilantin), pain relievers such as codeine, selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine (Prozac, Sarafem) and fluvoxamine (Luvox), trihexyphenidyl (Artane), and vitamins.  
  • in addition to the condition listed in the IMPORTANT WARNING section, tell your doctor if you have or have ever had blood disorders; heart, kidney, or liver disease; depression; epilepsy; problems with your urinary system or prostate; glaucoma; irregular heartbeat; problems with your blood pressure; or blood problems caused by clozapine.  
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking clozapine, call your doctor.  
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking clozapine.  
  • you should know that this drug may make you drowsy.  
  • remember that alcohol can add to the drowsiness caused by this drug.  
  • tell your doctor if you use tobacco products. Cigarette smoking may decrease the effectiveness of this drug.

What should I do if I forget a dose?

If you take clozapine several times a day, take the missed dose as soon as you remember it and take any remaining doses for that day at evenly spaced intervals. However, if you remember a missed dose when it is almost time for your next scheduled dose, skip the missed dose.

If you take clozapine once a day at bedtime and do not remember it until the next morning, skip the missed dose. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?

Although side effects from clozapine are not common, they can occur. Tell your doctor if any of these symptoms are severe or do not go away:

     
  • drowsiness  
  • dry mouth  
  • diarrhea  
  • constipation  
  • restlessness  
  • headache

If you experience any of the following symptoms or those listed in the IMPORTANT WARNINGS section, call your doctor immediately:

     
  • tremor  
  • seizures or convulsions  
  • difficulty urinating or loss of bladder control  
  • confusion  
  • eye pain  
  • shakiness  
  • chest pain  
  • severe muscle stiffness  
  • sore throat  
  • unusual bleeding or bruising  
  • upset stomach  
  • vomiting  
  • loss of appetite  
  • yellowness of the skin or eyes

Clozapine can cause high blood sugar (hyperglycemia). If you experience any of the following symptoms, call your doctor immediately:

     
  • thirst  
  • dry mouth  
  • tiredness  
  • flushing  
  • dry skin  
  • frequent urination  
  • loss of appetite  
  • trouble breathing

What storage conditions are needed for 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 excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
What other information should I know?

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

Johns Hopkins patient information

Copyright 1996-2014 Cerner Multum, Inc. Version: 16.02.
Revision date: June 21, 2011
Last revised: by Janet A. Staessen, MD, PhD

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