What is Clozaril: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Dec 30, 2020

Clozaril overview

BRAND NAMES:

  • Clozaril, Versacloz, Versacloz, Versacloz

Generic Names:

  • Clozapine

Uses:

  • Treats schizophrenia. Also lowers the risk of suicidal behavior in patients who have schizophrenia or schizoaffective disorder.

Therapeutic Classes:

  • Antipsychotic

Forms:

  • Liquid, Tablet, Dissolving Tablet

How it’s taken:

  • By mouth

What is Clozaril used for?

What form(s) does Clozaril come in

  • Liquid

  • Tablet

  • Dissolving Tablet

What are common Clozaril doses?

  • Tablet 25MG

  • Tablet 100MG

Common Clozaril prescriptions

  • Clozaril
    100mg tablet

  • Clozaril
    200mg tablet

  • Clozaril
    25mg tablet

  • Clozaril
    50mg tablet

How to take Clozaril

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.

  • Make sure your hands are dry before you handle the disintegrating tablet. Peel back the foil from the blister pack, then remove the tablet. Do not push the tablet through the foil. Place the tablet in your mouth. After it has melted, swallow or take a drink of water. The disintegrating tablet may also be chewed.

  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose. Call you doctor if you miss your dose for longer than 2 days. Your dose may need to be changed.

  • Oral suspension: Shake for 10 seconds before each use. Measure the dose with the dosing syringe that comes with the package.

  • Drink plenty of liquids to help avoid constipation.

  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Oral suspension: Do not refrigerate or freeze. Throw away any unused medicine 100 days after you open the bottle for the first time.

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Oral suspension: Do not refrigerate or freeze. Throw away any unused medicine 100 days after you open the bottle for the first time.

  • Make sure your hands are dry before you handle the disintegrating tablet. Peel back the foil from the blister pack, then remove the tablet. Do not push the tablet through the foil. Place the tablet in your mouth. After it has melted, swallow or take a drink of water. The disintegrating tablet may also be chewed.

  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.

  • Drink plenty of liquids to help avoid constipation.

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.

  • Oral suspension: Shake for 10 seconds before each use. Measure the dose with the dosing syringe that comes with the package.

  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose. Call you doctor if you miss your dose for longer than 2 days. Your dose may need to be changed.

What to do if you miss a dose of Clozaril

Clozaril contraindications

  • This medicine is not right for everyone. Do not use it if you had an allergic reaction to clozapine.

Clozaril warnings

  • Tell your doctor if you are pregnant, or if you have kidney disease, liver disease, dementia, diabetes, digestion problems, glaucoma, heart or blood vessel disease, heart failure, heart rhythm problems, high cholesterol, enlarged prostate, stomach or bowel problems, or a history of head injury, heart attack, stroke, seizures, or alcohol addiction. Tell your doctor if you smoke or drink products that contain caffeine. Tell your doctor if you have phenylketonuria.

  • Do not breastfeed while you are using this medicine.

  • This medicine may cause the following problems:Heart problems or changes in heart rhythmStomach or bowel problems, including severe constipationChanges in blood sugar levelsNeuroleptic malignant syndrome, which can be life-threateningLiver problemsIncreased risk of blood clots, including heart attack or strokeAnticholinergic effects, when used with other medicinesTardive dyskinesia (a movement disorder)

  • This medicine lowers the number of white blood cells. This weakens your immune system, so you may get infections more easily. Wash your hands often. Avoid people who are sick.

  • This medicine can make you dizzy, drowsy, lightheaded, or to have trouble with thinking or controlling body movements, which may lead to falls, fractures or other injuries. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. Stand or sit up slowly if you feel lightheaded or dizzy.

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

  • Jerky muscle movement that you cannot control, often in your face, tongue, or jaw

  • Lightheadedness, dizziness, fainting

  • Seizures

  • Unusual bleeding, bruising, or weakness

Clozaril interactions

  • Some medicines can affect how clozapine works. Tell your doctor if you are using any of the following:Bupropion, carbamazepine, cimetidine, dolasetron, duloxetine, enoxacin, escitalopram, fluoxetine, fluvoxamine, levomethadyl acetate, lithium, mefloquine, methadone, paroxetine, pentamidine, phenytoin, rifampin, sertraline, St John's wort, tacrolimus, or terbinafineBirth control pillsBlood pressure medicineDiuretic (water pill)Medicine for heart rhythm problems (including amiodarone, encainide, flecainide, procainamide, propafenone, quinidine, sotalol)Medicine to treat an infection (including ciprofloxacin, erythromycin, gatifloxacin, moxifloxacin, sparfloxacin)Other medicine to treat mental health problems (including chlorpromazine, droperidol, iloperidone, pimozide, thioridazine, ziprasidone).

  • Do not drink alcohol while you are using this medicine.

  • Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol.

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

  • Do not use this medicine together with benztropine, cyclobenzaprine, or diphenhydramine.

Clozaril side effects

Serious Side Effects

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing

  • Blistering, peeling, red skin rash

  • Blurred vision, confusion, trouble passing urine, eye pain, flushing or redness of the face, dry eyes, mouth, nose, or throat

  • Sweating, muscle stiffness

  • Unusual bleeding, bruising, or weakness

  • Severe constipation

  • Increased thirst or hunger

  • Seizures

  • Lightheadedness, dizziness, fainting

  • Fever, chills, cough, sore throat, body aches

  • Chest pain, trouble breathing, numbness or weakness on one side of your body, lower leg pain, problems with vision, speech, or walking

  • Jerky muscle movement that you cannot control, often in your face, tongue, or jaw

  • Fast, slow, pounding, or uneven heartbeat

  • Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes

Less Serious Side Effects

  • Weight gain

  • Unusual drowsiness or sleepiness, headache

  • Excess saliva or drooling

  • Weight gain