Clozapine

KLOE-za-peen

Oral routeTabletTablet, Disintegrating
  • Agranulocytosis
    • Because of a significant risk of agranulocytosis, a potentially life-threatening adverse event, clozapine should be reserved for use in (1) the treatment of severely ill patients with schizophrenia who fail to show an acceptable response to adequate courses of standard antipsychotic drug treatment, or (2) for reducing the risk of recurrent suicidal behavior in patients with schizophrenia or schizoaffective disorder who are judged to be at risk of reexperiencing suicidal behavior.
    • Patients being treated with clozapine must have a baseline white blood cell (WBC) count and absolute neutrophil count (ANC) before initiation of treatment as well as regular WBC counts and ANCs during treatment and for at least 4 weeks after discontinuation of treatment.
    • Clozapine is available only through a distribution system that ensures monitoring of WBC counts and ANCs according to the schedule described below prior to delivery of the next supply of medication.
  • Seizures
    • Seizures have been associated with the use of clozapine. Dose appears to be an important predictor of seizure, with a greater likelihood at higher clozapine doses. Caution should be used when administering clozapine to patients having a history of seizures or other predisposing factors. Patients should be advised not to engage in any activity where sudden loss of consciousness could cause serious risk to themselves or others.
  • Myocarditis
    • Analyses of postmarketing safety databases suggest that clozapine is associated with an increased risk of fatal myocarditis, especially during, but not limited to, the first month of therapy. In patients in whom myocarditis is suspected, clozapine treatment should be promptly discontinued.
  • Other Adverse Cardiovascular and Respiratory Effects
    • Orthostatic hypotension, with or without syncope, can occur with clozapine treatment. Rarely, collapse can be profound and be accompanied by respiratory and/or cardiac arrest. Orthostatic hypotension is more likely to occur during initial titration in association with rapid dose escalation. In patients who have had even a brief interval off clozapine (ie, 2 or more days since the last dose) treatment should be started with 12.5 mg once or twice daily.
    • Since collapse, respiratory arrest and cardiac arrest during initial treatment has occurred in patients who were being administered benzodiazepines or other psychotropic drugs, caution is advised when clozapine is initiated in patients taking a benzodiazepine or any other psychotropic drug.
  • Increased Mortality in Elderly Patients with Dementia-Related Psychosis
    • Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Analysis of seventeen placebo-controlled trials (modal duration of 10 weeks), largely in patients taking atypical antipsychotic drugs, revealed a risk of death in drug-treated patients of between 1.6 to 1.7 times the risk of death in placebo-treated patients. Over the course of a typical 10-week controlled trial, the rate of death in drug-treated patients was about 4.5%, compared to a rate of about 2.6% in the placebo group. Although the causes of death were varied, most of the deaths appeared to be either cardiovascular (eg, heart failure, sudden death) or infectious (eg, pneumonia) in nature. Observational studies suggest that, similar to atypical antipsychotic drugs, treatment with conventional antipsychotic drugs may increase mortality. The extent to which the findings of increased mortality in observational studies may be attributed to the antipsychotic drug as opposed to some characteristic(s) of the patients is not clear. Clozapine is not approved for the treatment of patients with dementia-related psychosis .

Risks associated with the use of clozapine include agranulocytosis, seizures, myocarditis, orthostatic hypotension, and respiratory and/or cardiac arrest. Patients being treated with clozapine must have a baseline white blood cell (WBC) count and absolute neutrophil count (ANC) before initiation of treatment as well as regular WBC counts and ANCs during treatment and for at least 4 weeks after discontinuation of treatment. Clozapine is only available through a distribution system that ensures monitoring of WBC count and ANC according to the schedule prior to delivery of the next supply of medication. Elderly patients with dementia-related psychosis treated with atypical antipsychotic drugs are at an increased risk of death compared to placebo, Although the causes of death in clinical trials were varied, most appeared to be cardiovascular (eg, heart failure, sudden death) or infectious (eg, pneumonia) in nature. Not approved for the treatment of patients with dementia-related psychosis. Observational studies suggest that antipsychotic drugs may increase mortality. It is unclear from these studies to what extent the mortality findings may be attributed to the antipsychotic drug as opposed to patient characteristics. Clozapine is not approved for the treatment of patients with dementia-related psychosis .

Commonly used brand name(s):

In the U.S.

  • Clozaril
  • FazaClo

Available Dosage Forms:

  • Tablet
  • Tablet, Disintegrating

Therapeutic Class: Antipsychotic

Chemical Class: Dibenzodiazepine

Uses For clozapine

Clozapine is used to treat schizophrenia in patients who have not been helped by or are unable to take other medicines. clozapine should NOT be used to treat behavioral problems in older adult patients who have dementia.

Clozapine is available only from pharmacies that agree to participate with your doctor in a plan to monitor your blood tests. You will need to have blood tests done every week for at least 6 months. After that, your doctor will decide if it is safe for you to have blood tests every other week. You will receive enough clozapine to last until your next blood test, but only if the results of your blood tests show that it is safe for you to take clozapine. If any of your blood tests are not normal, you may need to have blood tests more often than every week until they return to normal.

Before Using clozapine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For clozapine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to clozapine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of clozapine in the pediatric population. Safety and efficacy have not been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of clozapine in the elderly. However, elderly patients are more likely to have constipation or age-related liver, kidney, or heart problems, which may require caution in patients receiving clozapine. clozapine should not be used for behavioral problems in older adults with dementia.

Pregnancy

Pregnancy CategoryExplanation
All TrimestersBAnimal studies have revealed no evidence of harm to the fetus, however, there are no adequate studies in pregnant women OR animal studies have shown an adverse effect, but adequate studies in pregnant women have failed to demonstrate a risk to the fetus.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Using clozapine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Droperidol
  • Metoclopramide

Using clozapine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Buspirone
  • Carbamazepine
  • Lithium
  • Mate
  • Tramadol
  • Zotepine

Using clozapine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Aprindine
  • Cimetidine
  • Ciprofloxacin
  • Citalopram
  • Encainide
  • Erythromycin
  • Flecainide
  • Fluoxetine
  • Fluvoxamine
  • Lorcainide
  • Nefazodone
  • Nicotine
  • Paroxetine
  • Perphenazine
  • Phenobarbital
  • Phenytoin
  • Propafenone
  • Quinidine
  • Rifampin
  • Ritonavir
  • Sertraline
  • Thioridazine
  • Venlafaxine

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Using clozapine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use clozapine, or give you special instructions about the use of food, alcohol, or tobacco.

  • Caffeine

Other Medical Problems

The presence of other medical problems may affect the use of clozapine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Blood diseases (e.g., agranulocytosis, granulocytopenia), history of or
  • Bone marrow disorder or
  • Central nervous system depression (not fully awake), severe or
  • Intestinal blockage or
  • Seizures, uncontrolled—Should not be used in patients with these conditions.
  • Blood vessel problems (poor circulation) or
  • Heart attack, history of or
  • Heart failure or
  • Heart rhythm problems or
  • Hypotension (low blood pressure) or
  • Lung problems or
  • Stroke, history of—May cause side effects to become worse.
  • Constipation or
  • Diabetes or
  • Difficult urination or
  • Enlarged prostate or
  • Glaucoma, narrow angle or
  • Liver disease (e.g., hepatitis) or
  • Neuroleptic malignant syndrome, history of or
  • Seizures, history of—Use with caution. May make these conditions worse.
  • Kidney disease or
  • Liver disease—Higher blood levels of clozapine may occur, increasing the chance that unwanted effects will occur.

Proper Use of clozapine

Take clozapine exactly as directed. Do not take more of it and do not take it more often than your doctor ordered. Do not miss any doses.

clozapine has been prescribed for your current medical condition only. It must not be given to other people or used for other conditions. Talk to your doctor if you have questions.

Take the tablets with or without food.

Dosing

The dose of clozapine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of clozapine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For schizophrenia:
      • Adults—At first, 12.5 milligrams (mg) (one half of a 25-mg tablet) once or twice a day. Your doctor may increase your dose as needed. However, the dose is usually not more than 900 mg a day.
      • Children—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of clozapine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

If you miss 2 or more days of clozapine doses, talk to your doctor before you start taking it again. You may need to restart clozapine at a lower dose than you were taking before.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions While Using clozapine

It is important that you have your blood tests done when they are scheduled, and that your doctor check your progress at regular visits. Clozapine can cause some very serious blood problems that you may not be able to feel or see. The pharmacy will give you clozapine only if your blood tests show that it is safe for you to take clozapine. Also, your doctor will make sure the medicine is working properly and change the dosage if needed.

If you have been using clozapine regularly, do not stop taking it without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping it completely. This is to help prevent the illness from suddenly returning and to decrease the chance of having symptoms such as headache, nausea, vomiting or diarrhea.

clozapine will add to the effects of alcohol and other central nervous system (CNS) depressants, which are medicines that slow down the nervous system and possibly cause drowsiness. Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using clozapine.

Clozapine can temporarily lower the number of white blood cells in your blood, which increases the chance of getting an infection. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection:

  • If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
  • Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
  • Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.

Contact your doctor as soon as possible if you have chest pain or discomfort, a fast heartbeat, trouble breathing, or fever and chills. These can be symptoms of a very serious problem with your heart.

Clozapine may cause drowsiness, blurred vision or convulsions (seizures). Do not drive, climb, swim, operate machines or do anything else that could be dangerous while you are taking clozapine.

Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position suddenly. Getting up slowly may help. If this problem continues or gets worse, check with your doctor.

clozapine may increase the amount of sugar in your blood. Check with your doctor right away if you have increased thirst or urination. Diabetic patients should check their blood and urine sugar levels more often while taking clozapine. The dose of diabetic medicines may need to be changed.

In some patients, clozapine may cause increased watering of the mouth. Other patients, however, may get dryness of the mouth. For temporary relief of mouth dryness, use sugarless gum or candy, melt bits of ice in your mouth, or use a saliva substitute. However, if your mouth continues to feel dry for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.

Check with your doctor right away if you are having convulsions (seizures); difficulty with breathing; fast heartbeat; high fever; high or low blood pressure; increased sweating; loss of bladder control; severe muscle stiffness; unusually pale skin; or tiredness. These could be symptoms of a serious condition called neuroleptic malignant syndrome (NMS).

clozapine may cause tardive dyskinesia (a movement disorder) among the elderly, especially elderly women. Check with your doctor right away if you have any of the following symptoms while taking clozapine: lip smacking or puckering, puffing of the cheeks, rapid or worm-like movements of the tongue, uncontrolled chewing movements, or uncontrolled movements of the arms and legs.

Make sure any doctor or dentist who treats you knows that you are using clozapine. You may need to stop using clozapine several days before having surgery or medical tests.

clozapine Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Some side effects may not have signs or symptoms that you can see or feel. Clozapine can cause some very serious blood problems. Your doctor will watch for these by doing blood tests every week or two for as long as you are taking clozapine and for 4 weeks after you stop taking it. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common
  • Blurred vision
  • confusion
  • dizziness, faintness, or lightheadedness when getting up from a lying or sitting position suddenly
  • fainting
  • fast, pounding, or irregular heartbeat or pulse
  • fever
  • low blood pressure
  • shakiness in legs, arms, hands, or feet
  • sleepiness or unusual drowsiness
  • sweating
  • trembling or shaking of hands or feet
  • unusual tiredness or weakness
Less common
  • Anxiety
  • black, tarry stools
  • chest pain
  • chills
  • convulsions
  • cough or hoarseness
  • decrease in frequency of urination
  • decrease in urine volume
  • difficult or labored breathing
  • difficulty in passing urine (dribbling)
  • discouragement
  • dry mouth
  • fear or nervousness
  • feeling sad or empty
  • fever with or without chills
  • frequent strong or increased urge to urinate
  • general feeling of tiredness or weakness
  • headache
  • hyperventilation
  • irritability
  • lack of appetite
  • loss of bladder control
  • loss of interest or pleasure
  • lower back or side pain
  • mood or mental changes
  • muscle spasm or jerking of all extremities
  • painful or difficult urination
  • pounding in the ears
  • restlessness or need to keep moving
  • severe or continuing headache
  • shakiness and unsteady walk
  • shortness of breath
  • slurred speech
  • sore throat
  • sores, ulcers, or white spots on lips or in mouth
  • sudden jerky movements of body
  • sudden loss of consciousness
  • swollen glands
  • throat discomfort
  • tightness in chest
  • trouble concentrating
  • trouble sleeping
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • wheezing
Rare
  • Absence of or decrease in movement
  • dark urine
  • decreased appetite
  • decreased sexual ability
  • difficult or fast breathing or sudden shortness of breath
  • increased appetite
  • increased sweating
  • increased thirst
  • increased urination
  • lip smacking or puckering
  • loss of bladder control
  • mental depression
  • muscle stiffness (severe)
  • nausea
  • puffing of the cheeks
  • rapid or worm-like movements of the tongue
  • swelling or pain in leg
  • trouble breathing
  • trouble in urinating
  • uncontrolled chewing movements
  • uncontrolled movements of the arms and legs
  • unusual bleeding or bruising
  • unusually pale skin
  • vomiting
  • weakness
  • yellow eyes or skin
Incidence not known
  • Abdominal or stomach pain
  • bloating
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • clay-colored stools
  • confusion as to time, place, or person
  • constipation
  • darkened urine
  • diarrhea
  • epileptic seizure that will not stop
  • feeling that others are watching you or controlling your behavior
  • feeling that others can hear your thoughts
  • feeling, seeing, or hearing things that are not there
  • holding false beliefs that cannot be changed by fact
  • inability to move eyes
  • increased blinking or spasms of eyelid
  • indigestion
  • itching
  • joint pain
  • light-colored stools
  • muscle twitching
  • pains in stomach, side, or abdomen, possibly radiating to the back
  • rhythmic movement of muscles
  • severe mood or mental changes
  • skin rash
  • sticking out of tongue
  • swelling around the eyes
  • swelling of body or feet and ankles
  • trouble in breathing, speaking, or swallowing
  • uncontrolled twisting movements of neck, trunk, arms, or legs
  • unpleasant breath odor
  • unusual behavior
  • unusual excitement, nervousness, or restlessness
  • unusual facial expressions
  • unusual weight gain
  • upper right abdominal pain
  • vomiting of blood
  • yellow eyes or skin

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose
  • Change in consciousness
  • drowsiness
  • increased watering of mouth (severe)
  • irregular, fast or slow, or shallow breathing
  • loss of consciousness
  • pale or blue lips, fingernails, or skin
  • pounding or rapid pulse

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Acid or sour stomach
  • belching
  • feeling of constant movement of self or surroundings
  • heartburn
  • relaxed and calm sensation of spinning
  • sleepiness
  • sleeplessness
  • unable to sleep
Less common
  • Blurred or loss of vision
  • change or problem with discharge of semen
  • disturbed color perception
  • double vision
  • halos around lights
  • inability to sit still
  • increase in body movements
  • muscle pain or ache
  • muscle weakness
  • night blindness
  • nightmares
  • overbright appearance of lights
  • pain in the back, neck, or legs
  • pain in the chest below the breastbone
  • severe muscle stiffness
  • sore tongue
  • stuffy nose
  • tunnel vision
  • unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
Incidence not known
  • Blistering, peeling, or loosening of skin
  • difficulty swallowing
  • hives
  • increased sensitivity of skin to sunlight
  • painful or prolonged erection of the penis
  • red, irritated eyes
  • red skin lesions, often with a purple center
  • reddening of the skin, especially around ears
  • severe stomach pain
  • severe sunburn
  • sores, welting, or blisters
  • swelling of eyes, face, or inside of nose
  • swelling of salivary glands

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

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  • Clozapine Prescribing Information (FDA)
  • Clozapine Professional Patient Advice (Wolters Kluwer)
  • Clozapine Detailed Consumer Information (PDR)
  • Clozapine MedFacts Consumer Leaflet (Wolters Kluwer)
  • Clozaril Prescribing Information (FDA)
  • Clozaril Consumer Overview
  • FazaClo Orally Disintegrating Tablets MedFacts Consumer Leaflet (Wolters Kluwer)
  • FazaClo Prescribing Information (FDA)
  • Fazaclo Consumer Overview