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 this medicine 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 this medicine 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.
This medicine 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; medicine for seizures or barbiturates; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine.
Clozapine can temporarily lower the number of white blood cells in your blood, which increases the chance of getting an infection. Let your doctor know right away if you think you have the flu or an infection. Possible signs and symptoms include fever, feeling tired, sore throat, or weakness. Certain precautions you can take when your blood count is low to reduce the risk of infection include:
- 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.
Stop using this medicine and 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 this medicine.
This medicine can cause changes in heart rhythms, such as a condition called QT prolongation. It may change the way your heart beats and cause fainting or serious side effects in some patients. Contact your doctor right away if you have any symptoms of heart rhythm problems, such as fast, pounding, or uneven heartbeats.
Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position suddenly. These symptoms are more likely to occur when you begin taking this medicine, or when the dose is increased. Getting up slowly may help. If this problem continues or gets worse, check with your doctor.
This medicine 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 this medicine. 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).
This medicine may cause tardive dyskinesia (a movement disorder) among the elderly, especially elderly women. Stop using this medicine and check with your doctor right away if you have any of the following symptoms while taking this medicine: 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.
Stop using this medicine and check with your doctor right away if you have pain or tenderness in the upper stomach; pale stools; dark urine; loss of appetite; nausea; unusual tiredness or weakness; or yellow eyes or skin. These could be symptoms of a serious liver problem.
Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine several days before having surgery or medical tests.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.