Uses
See also Warning section.
This medication is used to treat certain mental/mood disorders (schizophrenia, schizoaffective disorders). Clozapine may also help prevent suicide in people who are likely to try to harm themselves. Clozapine belongs to a class of drugs known as atypical antipsychotics. It works by helping to restore the balance of certain natural substances in the brain.
How To Use
If you are using the liquid form of this medication, read the Patient Information Leaflet if available from your pharmacist before you start taking clozapine and each time you get a refill. If you have any questions, ask your doctor or pharmacist.
Take this medication by mouth with or without food, as directed by your doctor. If you are taking the tablets that dissolve in the mouth, carefully remove each tablet from the blister pack immediately before taking your dose. Allow the tablets to dissolve on your tongue and swallow. You do not need to take the dissolving tablets with water. Discard any dissolving tablets that have been previously exposed to air due to opened/damaged packaging. Do not save them for your next dose.
If you are using the liquid form of this medication, shake the bottle well for 10 seconds before each use. Carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.
It is important to begin taking this drug at a low dose, increasing your dose slowly, to lessen side effects such as dizziness, drowsiness and seizures. Follow your doctor's instructions exactly. Your dosage is based on your medical condition and response to therapy. Since clozapine can cause a decrease in white blood cells, you will need to get blood tests done regularly as directed. Be sure to keep all appointments for these lab tests. (See also Notes section.)
If you miss your doses for longer than a day or two, consult your doctor for a new schedule to get back to the dose you were on (see Missed Dose section). Use this medication regularly in order to get the most benefit from it. To help you remember, use it at the same time(s) each day.
Do not stop taking clozapine without consulting your doctor. Some conditions may become worse when the drug is suddenly stopped. Also, you may experience symptoms such as severe sweating, headache, nausea, vomiting, and diarrhea. To prevent these symptoms while you are stopping treatment with this drug, your doctor may reduce your dose gradually. Consult your doctor or pharmacist for more details. Report any new or worsening symptoms right away.
It may take several weeks before the full benefit of this drug takes effect. Tell your doctor if your condition lasts or gets worse.
Side Effects
See also Warning section.
Drooling, drowsiness, dizziness, lightheadedness, headache, shaking (tremor), vision problems (such as blurred vision), constipation, and weight gain may occur. Many of these effects (especially drowsiness) lessen as your body gets used to the medication. If any of these effects last or get worse, tell your doctor or pharmacist promptly.
To prevent constipation, eat dietary fiber, drink enough water, and exercise. You may also need to take a laxative. Ask your pharmacist which type of laxative is right for you.
Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
This medication may rarely make your blood sugar rise, which can cause or worsen diabetes. Tell your doctor right away if you have symptoms of high blood sugar such as increased thirst/urination. If you already have diabetes, check your blood sugar regularly as directed and share the results with your doctor. Your doctor may need to adjust your diabetes medication, exercise program, or diet.
This drug may also cause significant weight gain and a rise in your cholesterol (or triglyceride) levels. These effects, along with diabetes, may increase your risk for developing heart disease. Discuss the risks and benefits of treatment with your doctor.
Tell your doctor right away if you have any serious side effects, including:
- facial/muscle twitching
- seizures
- uncontrollable movements
- interrupted breathing during sleep
- trouble urinating
- severe constipation
Get medical help right away if you have any very serious side effects, including:
- nausea/vomiting that doesn't stop
- severe dizziness
- fainting
- mental/mood changes
- difficulty breathing with exercise
- sudden weakness
- pain/redness/swelling of the arms/legs
- stomach/abdominal pain
- yellowing of eyes/skin
This medication may rarely cause a very serious condition called neuroleptic malignant syndrome (NMS). Get medical help right away if you have any of the following symptoms:
- fever
- muscle stiffness/pain/tenderness/weakness
- severe tiredness
- severe confusion
- sweating
- fast/irregular heartbeat
- dark urine
- signs of kidney problems (such as change in the amount of urine)
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:
- rash
- itching/swelling (especially of the face/tongue/throat)
- severe dizziness
- trouble breathing
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Precautions
See also Warning and Side Effects sections.
Before taking clozapine, tell your doctor or pharmacist if you are allergic to it or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of:
- history of blood disorders (such as leukemia, low white blood cell count)
- bowel problems (such as paralytic ileus, irritable bowel syndrome )
- breathing problems
- diabetes/family history of diabetes
- high cholesterol/triglyceride levels
- glaucoma
- heart problems
- kidney problems
- liver problems
- obesity/family history of obesity
- seizures
- difficulty urinating (for example, due to enlarged prostate)
- breathing trouble during sleep (sleep apnea)
Clozapine may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.
The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may affect the heart rhythm. Before using clozapine, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions:
- certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG)
- family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death)
Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using clozapine safely.
This drug may make you dizzy or drowsy or blur your vision. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).
Tell your doctor if you are a descendent of Ashkenazi Jews because you may be at a higher risk for a drop in your white blood cells.
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Liquid products or dissolving tablets may contain sugar and/or aspartame. Liquid products may also contain alcohol. Caution is advised if you have diabetes, liver disease, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using this product safely.
Older adults may be more sensitive to the side effects of this drug, especially constipation, trouble urinating, drowsiness, dizziness, lightheadedness, and QT prolongation (see above). Drowsiness, dizziness, and lightheadedness can increase the risk of falling.
During pregnancy, this medication should be used only when clearly needed. Babies born to mothers who have used this drug during the last 3 months of pregnancy may rarely develop symptoms including muscle stiffness or shakiness, drowsiness, feeding/breathing difficulties, or constant crying. If you notice any of these symptoms in your newborn especially during their first month, tell the doctor right away.
Since untreated mental/mood problems (such as schizophrenia, schizoaffective disorders) can be a serious condition, do not stop taking this medication unless directed by your doctor. If you are planning pregnancy, become pregnant, or think you may be pregnant, immediately discuss with your doctor the benefits and risks of using this medication during pregnancy.
Clozapine may pass into breast milk and have undesirable effects on a nursing infant. Breastfeeding is not recommended while using this medication. Consult your doctor before breastfeeding.
Drug Interactions
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
A product that may interact with this drug is:
Other medications can affect the removal of clozapine from your body, which may affect how clozapine works. Examples include fluvoxamine, saquinavir, St. John's wort, drugs used to treat seizures (such as carbamazepine, phenytoin), among others.
Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine).
Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.
Cigarette smoking decreases blood levels of this medication. Tell your doctor if you smoke or if you have recently stopped smoking.
Overdose
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Alberta residents can call PADIS (Poison and Drug Information Service) 24 hours a day at 1-800-332-1414. Canada residents can call a provincial poison control center.
Notes
Do not share this medication with others.
Lab and/or medical tests (such as complete blood count, liver function, blood sugar, weight, cholesterol/triglyceride levels) must be done before you start taking this medication and while you are taking it. Clozapine blood levels may also be checked. Keep all medical and lab appointments. Consult your doctor for more details.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. If you miss doses for longer than a day or two, consult your doctor for a new schedule to get back to the dose you were taking. Do not double the dose to catch up.
If you have questions about missing a dose or you don't have more medication, contact your healthcare provider or pharmacist.
Storage
Store at room temperature away from light and moisture. Store the dissolving tablets in their blister packets, and do not remove each dose until just before taking. Do not store in the bathroom. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
