Generic Name: clozapine (KLOE za peen)
Brand Names: Clozaril, FazaClo, Versacloz, Clopine, CloZAPine Synthon, Denzapine, Zaponex
Medically reviewed by Sanjai Sinha, MD Last updated on Feb 10, 2019.
What is clozapine?
Clozapine is an antipsychotic medication. It works by changing the actions of chemicals in the brain.
Clozapine is used to treat severe schizophrenia, or to reduce the risk of suicidal behavior in people with schizophrenia or similar disorders.
Clozapine is available only from a certified pharmacy under a special program.
Call your doctor right away if you have: chest pain, trouble breathing, fluttering in your chest, signs of infection (weakness, fever, sore throat, cold or flu symptoms), or if you feel like you might pass out.
Clozapine can cause severe dizziness, slow heartbeats, fainting, or seizures. Do not take more of this medicine than recommended.
Clozapine is not approved for use in psychotic conditions related to dementia. This medicine may increase the risk of death in older adults with dementia-related conditions.
Clozapine is available only from a certified pharmacy under a special program.
Before taking this medicine
You should not take clozapine if you have ever developed a severe infection or severe allergic reaction while taking this medicine.
Clozapine is not approved for use in psychotic conditions related to dementia. Clozapine may increase the risk of death in older adults with dementia-related conditions.
To make sure clozapine is safe for you, tell your doctor if you have:
heart disease, high blood pressure, or history of heart attack or stroke (including "mini-stroke");
a personal or family history of long QT syndrome;
an electrolyte imbalance (such as low levels of potassium or magnesium in your blood);
a history of seizures, head injury, or brain tumor;
diabetes, or risk factors such as being overweight or having a family history of diabetes;
high cholesterol or triglycerides;
a bowel obstruction called paralytic ileus;
liver or kidney disease;
an enlarged prostate or urination problems;
if you are malnourished or dehydrated; or
if you smoke.
Tell your doctor if you are pregnant or plan to become pregnant during treatment. Taking antipsychotic medication during the last 3 months of pregnancy may cause problems in the newborn, such as withdrawal symptoms, breathing problems, feeding problems, fussiness, tremors, and limp or stiff muscles. However, you may have withdrawal symptoms or other problems if you stop taking your medicine during pregnancy. If you become pregnant while taking clozapine, do not stop taking it without your doctor's advice.
Clozapine can pass into breast milk and may harm a nursing baby. You should not breast-feed while you are taking this medicine.
How should I take clozapine?
Take clozapine exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not use this medicine in larger or smaller amounts or for longer than recommended.
Clozapine can be taken with or without food.
The orally-disintegrating tablet (FazaClo) can be taken without water. Keep the tablet in its blister pack until you are ready to take it. Open the package and peel back the foil. Do not push a tablet through the foil or you may damage the tablet. Use dry hands to remove the tablet and place it in your mouth. Do not swallow the tablet whole. Allow it to dissolve in your mouth without chewing. If desired, you may drink liquid to help swallow the dissolved tablet.
If your doctor has prescribed one-half of an orally-disintegrating tablet, you will need to break the tablet in half. Throw the other half away. Do not save it for later use.
Clozapine can lower blood cells that help your body fight infections, especially in women and older adults, and in people who are malnourished or have serious medical problems. This can make it easier for you to develop a serious or life-threatening infection. Your blood will need to be tested often. Your future treatments may be delayed based on the results of these tests.
If you need surgery, tell the surgeon ahead of time that you are using clozapine. You may need to stop using the medicine for a short time.
You should not stop using clozapine suddenly or you could have unpleasant withdrawal symptoms. Follow your doctor's instructions about tapering your dose.
Clozapine can have long lasting effects on your body. You may need frequent medical tests for a short time after you stop using this medicine.
Store at room temperature away from moisture and heat.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose. If you miss taking clozapine for more than 2 days in a row, call your doctor before you start taking it again.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking clozapine?
Clozapine can cause severe dizziness, slow heartbeats, fainting, or seizures. Do not take more of this medicine than recommended. Be careful if you drive or do anything that requires you to be alert. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Dizziness or severe drowsiness can cause falls, fractures, or other injuries.
Avoid drinking alcohol. Dangerous side effects could occur.
Clozapine side effects
Get emergency medical help if you have signs of an allergic reaction to clozapine: hives, skin pain, rash that spreads and causes blistering or peeling; difficult breathing; swelling of your face, lips, tongue, or throat.
Serious and sometimes fatal infections may occur during treatment with clozapine. Call your doctor right away if you have signs of infection such as: weakness, fever, swollen gums, sore throat, painful mouth sores, pain when swallowing, skin sores, cold or flu symptoms, cough, trouble breathing.
High doses or long-term use of clozapine can cause a serious movement disorder that may not be reversible. Symptoms of this disorder include uncontrollable muscle movements of your lips, tongue, eyes, face, arms, or legs. The longer you take this medicine, the more likely you are to develop a serious movement disorder. The risk of this side effect is higher in women and older adults.
Also call your doctor at once if you have:
headache with chest pain and severe dizziness, pounding heartbeats or fluttering in your chest;
a light-headed feeling, like you might pass out;
sudden cough, rapid breathing, coughing up blood;
tight feeling in your neck or jaw, twitching or uncontrollable muscle movements;
a seizure (blackout or convulsions);
kidney problems - little or no urination, swelling in your feet or ankles, feeling tired or short of breath;
liver problems - nausea, upper stomach pain, loss of appetite, tiredness, confusion, unusual bleeding, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);
severe nervous system reaction - very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out;
high blood sugar - increased thirst, increased urination, hunger, dry mouth, fruity breath odor, drowsiness, dry skin, blurred vision, weight loss; or
signs of inflammation in your body - easy bruising or bleeding, severe tingling or numbness, muscle weakness, upper stomach pain, jaundice (yellowing of the skin or eyes), chest pain, new or worsening cough, trouble breathing.
Common clozapine side effects may include:
tremor, dizziness, spinning sensation;
dry mouth, or increased salivation;
blurred vision; or
fast heart rate, increased sweating.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect clozapine?
Clozapine can cause a serious heart problem, especially if you use certain medicines at the same time. Tell your doctor about all medicines you use, and those you start or stop using during your treatment.
Taking clozapine with other drugs that make you sleepy or slow your breathing can cause dangerous or life-threatening side effects. Ask your doctor before taking this medicine with a sleeping pill, narcotic pain medicine, prescription cough medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.
Many drugs can interact with clozapine. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any you start or stop using, especially:
dolasetron, methadone, probucol, tacrolimus;
an antibiotic - ciprofloxacin, enoxacin, erythromycin, pentamidine, rifampin;
an antidepressant - citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline;
anti-malaria medication - mefloquine, halofantrine;
heart rhythm medicine - amiodarone, encainide, flecainide, procainamide, propafenone, quinidine, sotalol;
medicine to treat a psychiatric disorder - chlorpromazine, droperidol, haloperidol, iloperidone, pimozide, thioridazine, ziprasidone; or
seizure medication - carbamazepine, phenytoin.
This list is not complete and many other drugs can interact with clozapine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use clozapine only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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More about clozapine
- Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Images
- Drug Interactions
- Support Group
- Pricing & Coupons
- En Español
- 44 Reviews
- Drug class: atypical antipsychotics
- FDA Alerts (7)
- Clozapine Orally Disintegrating Tablets
- Clozapine Tablets
- Clozapine Oral Suspension
- Clozapine (Advanced Reading)