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chlorpromazine vs clozapine

Side-by-side comparison of chlorpromazine and clozapine. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

minor Known Drug Interaction

Drugs that cause QT prolongation include: specific antipsychotics (e.g., ziprasidone, iloperidone, chlorpromazine, thioridazine, mesoridazine, droperidol, and pimozide), specific antibiotics (e.g., erythromycin, gatifloxacin, moxifloxacin, sparfloxacin), Class 1A antiarrhythmics (e.g., quinidine, procainamide) or Class III antiarrhythmics (e.g., amiodarone, sotalol), and others (e.g., pentamidine, levomethadyl acetate, methadone, halofantrine, mefloquine, dolasetron mesylate, probucol or tacrolimus) [see Warnings and Precautions (5.9) ] .

Recommendation: Your healthcare provider should perform regular heart tests while you are on both medications. They may need to adjust your treatment if they see changes in your heart rhythm.

Drug Class
chlorpromazine Typical Antipsychotic (Phenothiazine)
clozapine Atypical Antipsychotic
Type
chlorpromazine Prescription
clozapine Prescription
Summary
chlorpromazine

Chlorpromazine is a medicine that belongs to a class of drugs called phenothiazine antipsychotics. It can help manage symptoms of certain mental disorders by affecting chemical messengers in the brain.

clozapine

Versacloz is a medicine used to treat severe schizophrenia when other medicines have not worked. It can also help lower the risk of suicidal behavior in people with schizophrenia or schizoaffective disorder.

What It Treats
chlorpromazine

Chlorpromazine can treat psychotic disorders like schizophrenia. It can also control nausea and vomiting. Additionally, it can help with restlessness before surgery, acute intermittent porphyria, tetanus, manic episodes of bipolar disorder, and intractable hiccups. In children, it can treat severe behavioral problems and hyperactivity.

clozapine

Versacloz is used to treat schizophrenia in people who haven't responded well to other antipsychotic medicines. Schizophrenia is a mental illness that can cause hallucinations, delusions, and disorganized thinking. Versacloz can also help lower the risk of repeated suicidal behavior in people with schizophrenia or schizoaffective disorder who are at high risk.

How It Works
chlorpromazine

Chlorpromazine works by changing the effect of certain natural chemicals in the brain. It blocks dopamine receptors, which helps to reduce psychotic symptoms. It also affects other neurotransmitters, such as histamine and acetylcholine.

clozapine

Versacloz works by affecting certain chemicals in the brain. These chemicals, like dopamine and serotonin, are involved in mood, behavior, and thinking. By changing the levels of these chemicals, Versacloz can help reduce symptoms of schizophrenia and lower the risk of suicidal behavior.

Common Side Effects
chlorpromazine
  • Drowsiness
clozapine
  • Feeling sleepy
  • Dizziness
  • Headache
  • Shaking
  • Fast heart rate
FAERS Reports
chlorpromazine
  • Harmful effects from different substances 426
  • Taking too much medicine 345
  • Medicines affecting each other 322
  • A severe reaction to antipsychotic drugs causing fever, muscle stiffness, and altered mental status 280
  • Feeling sick to your stomach 272
clozapine
  • Low white blood cell count 18,655
  • Needing to stay in the hospital 12,101
  • Death 11,398
  • A mental disorder that affects how a person thinks, feels, and behaves 4,547
  • High white blood cell count 4,446
Serious Warnings
chlorpromazine

Antipsychotic medicines like chlorpromazine can increase the risk of death in elderly patients who have dementia-related psychosis. Chlorpromazine is not approved for treating this condition.

clozapine

Versacloz can cause several serious side effects: * **Severe Neutropenia:** This means a dangerously low white blood cell count, which increases your risk of infection. You will need regular blood tests to check your white blood cell count. * **Orthostatic Hypotension, Bradycardia, and Syncope:** This means low blood pressure when standing up, slow heart rate, and fainting. These are most likely when you first start taking Versacloz or when the dose is increased. * **Seizures:** Versacloz can increase your risk of seizures, especially at higher doses. * **Myocarditis, Pericarditis, and Cardiomyopathy:** These are serious heart problems that can be fatal. Tell your doctor right away if you have chest pain, shortness of breath, or other heart-related symptoms. * **Increased Mortality in Elderly Patients with Dementia-Related Psychosis:** Elderly patients with dementia who take antipsychotic medicines like Versacloz have an increased risk of death.

Pregnancy
chlorpromazine

Tell your doctor if you are pregnant or plan to become pregnant. It is not known if chlorpromazine will harm your unborn baby. Talk to your doctor about the risks and benefits of taking this medicine during pregnancy and breastfeeding.

clozapine

Tell your doctor if you are pregnant or plan to become pregnant. Babies born to mothers who take Versacloz in the third trimester may have withdrawal symptoms or other problems after birth. There is a pregnancy registry for women who take atypical antipsychotics like Versacloz.

Also Compare, Nearby Drugs

How to Read This chlorpromazine vs clozapine Comparison

chlorpromazine is classified in the Typical Antipsychotic (Phenothiazine) drug class, while clozapine sits within the Atypical Antipsychotic class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.

Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, chlorpromazine has 1,645 submissions while clozapine has 51,147. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to these two drugs both affect the heart's electrical system in the same way. using them at the same time can lead to serious heart rhythm problems.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between chlorpromazine and clozapine - always consult your physician or pharmacist first.

Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.