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Chlorpromazine: Side Effects, Uses, Dosage, Interactions, Warnings

Chlorpromazine

Reviewed on 4/27/2023

What Is Chlorpromazine and How Does It Work?

Chlorpromazine is a prescription medication used to treat the symptoms of Schizophrenia, Psychotic Disorders, Nausea and Vomiting, Preoperative Apprehension, Intraoperative Sedation, Intractable Hiccups, and Acute Intermittent Porphyria

Chlorpromazine is available under the following different brand names: Thorazine

Dosages of Chlorpromazine

Adult and Pediatric dosage

Tablet

  • 10mg
  • 25mg
  • 50mg
  • 100mg
  • 200mg

Injectable solution

  • 25mg/mL 

Schizophrenia, Psychotic Disorders

Adult dosage

  • Orally: 30-75 mg per day divided every 6-12 hours initially; maintenance: usually 200 mg per day (up to 800 mg per day in some patients; some patients may require 1-2 g per day)
  • IV/IM: 25 mg initially, followed as needed with 25-50 mg after 1-4 hours, then increased to maximum of 400 mg every 4-6 hours until is controlled; usual dosage 300-800 mg per day

Behavioral Disorders, Hyperactivity

Pediatric Dosage

  • Younger than 6 months of age: Safety and efficacy not established
  • 6 months and older: 50-100 mg per day orally or IM; 200 mg per day or more may be necessary for older hospitalized patients; for outpatients, may administer 0.55 mg/kg every 4-6 hours as needed

Nausea and Vomiting

Adult Dosage

  • Orally: 10-25 mg every 4-6 hours as needed
  • IV/IM: 25-50 mg ever 4-6 hours as needed

Pediatric Dosage

  • Younger than 6 months of age: Safety and efficacy not established
  • 6 months and older: 0.5-1 mg/kg orally or IM every 6-8 hours as needed

Preoperative Apprehension

Adult Dosage

  • 25-50 mg orally 2-3 hours before surgery
  • 12.5-25 mg IM 1-2 hours before surgery

Pediatric Dosage

  • Younger than 6 months of age: Safety and efficacy not established
  • 6 months and older: 0.55 mg/kg orally or IM 1-2 hours before surgery

Intraoperative Sedation

Adult Dosage

  • 12.5 IM every 30 minutes or 2 mg IV every 2 minutes; total dose not to exceed 25 mg

Intractable Hiccups

Adult Dosage

  • 25-50 mg orally every 6-8 hours; if hiccups persist after 2-3 days of oral therapy, administer 25-50 mg IM every 3-4 hours; if symptoms persist, administered 25-50 mg by slow IV infusion with patient lying flat in a bed; monitor blood pressure

Acute Intermittent Porphyria

Adult Dosage

  • 25-50 mg orally every 6-8 hours

Dosage Considerations – Should be Given as Follows: 

  • See "Dosages."

What Are Side Effects Associated with Using Chlorpromazine?

Common side effects of Chlorpromazine include:

Serious side effects of Chlorpromazine include:

  • hives, 
  • difficulty breathing, 
  • swelling of your face, lips, tongue, or throat, 
  • uncontrolled muscle movements in your face (chewing, lip smacking, frowning, tongue movement, blinking or eye movement), 
  • stiffness in your neck, 
  • tightness in your throat, 
  • trouble swallowing, 
  • lightheadedness
  • confusion, 
  • agitation, 
  • feeling jittery, 
  • trouble sleeping, 
  • weakness, 
  • breast swelling or discharge
  • seizure
  • yellowing of the skin or eyes (jaundice), 
  • fever, 
  • chills, 
  • mouth sores, 
  • skin sores, 
  • sore throat
  • cough, 
  • very stiff (rigid) muscles, 
  • high fever, 
  • sweating, 
  • confusion, 
  • fast or uneven heartbeats, and
  • tremors 

Rare side effects of Chlorpromazine include:

  • none 

This is not a complete list of side effects and other serious side effects or health problems may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Chlorpromazine?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them.  Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first

  • Chlorpromazine has severe interactions with the following drugs:
    • disopyramide
    • eliglustat
    • ibutilide
    • indapamide
    • metrizamide
    • pentamidine
    • pimozide
    • procainamide
    • quinidine
    • sotalol  
  • Chlorpromazine has serious interactions with at least 109 other drugs.
  • Chlorpromazine has moderate interactions with at least 318 other drugs.
  • Chlorpromazine has minor interactions with at least 67 other drugs. 

This information does not contain all possible interactions or adverse effects.  Visit the RxList Drug Interaction Checker for any drugs interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use.  Keep a list of all your medications with you, and share this information with your doctor and pharmacist.  Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

What Are Warnings and Precautions for Chlorpromazine?

Contraindications

Effects of drug abuse

  • None

Short-Term Effects

  • See “What are Side Effects Associated with Using Chlorpromazine?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Chlorpromazine?”

Cautions

  • Avoid using in children with suspected Reye syndrome
  • Use caution in glaucoma, prostatic hypertrophy, stenosing peptic ulcer disease (PUD), history of NMS, Parkinson disease, hypocalcemia, renal or hepatic impairment, history of severe reaction to insulin or electroconvulsive therapy (ECT), history of seizures, asthma, respiratory tract infection, cardiovascular disease, myelosuppression
  • Risk of extrapyramidal symptoms (EPS), NMS, hypotension
  • Significant hypotension may occur, especially with parenteral administration; hypotension may be particularly severe in patients with pheochromocytoma or mitral insufficiency; in case of severe hypotension, treat with norepinephrine or phenylepinephrine, and do not use epinephrine or dopamine
  • May alter cardiac conduction; life threatening arrhythmias reported with therapeutic doses of phenothiazines; may cause QT prolongation and subsequent torsade de pointes; avoid use in patients diagnosed or suspected congenital long QT syndrome
  • May cause anticholinergic effects; use caution in patients with paralytic ileus, gastrointestinal motility, urinary retention, xerostomia, or visual problems
  • Agranulocytosis, leukopenia, and neutropenia reported with antipsychotic use; periodic blood count assessment recommended in patients with history of risk factors, including history of drug-induced leuko/neutropenia or preexisting low WBC
  • Esophageal dysmotility and aspiration reported with antipsychotic use; use caution in patients at risk of pneumonia
  • May cause extrapyramidal symptoms, including akathisia, acute dystonic reactions, and pseudoparkinsonism, and tardive dyskinesia; risk of dystonia greater with increased doses
  • Therapy is associated with increased prolactin levels; significance unknown
  • May cause pigmentary retinopathy, and lenticular and corneal deposits with prolonged therapy
  • May cause orthostatic hypotension; use caution in patients with risk factors, including patients who do not tolerate transient hypotensive episodes such as hypovolemia, cerebrovascular disease, cardiovascular disease, or medication predisposing to hypotension/bradycardia
  • May impair physical or mental abilities due to sedating properties; use caution when operating heavy machinery
  • Depresses hypothalamic thermoregulatory mechanism; exposure to extreme temperatures may cause hypo- or hyperthermia
  • Antiemetic effect may obscure toxicity of chemotherapeutic drugs
  • Anticholinergic antiparkinsonian agent may be needed to counter EPS
  • Strong anticholinergic agent and alpha blocker
  • Potential for priapism

US Food and Drug Administration (FDA) warning regarding off-label use for dementia in elderly (see Black Box Warnings)

Pregnancy and Lactation

  • Neonates exposed to antipsychotic drugs during 3rd trimester of pregnancy are at risk for EPS or withdrawal symptoms after delivery; these complications vary in severity, with some being self-limited and others necessitating ICU support and prolonged hospitalization
  • Drug enters breast milk; not recommended.
References
https://reference.medscape.com/drug/chlorpromazine-342970