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Side Effects of Chlorpromazine (Thorazine, Ormazine)


Side Effects of Chlorpromazine (Thorazine)

Chlorpromazine, known as the brands Thorazine and Ormazine, is part of the drug class phenothiazines, which are antipsychotic medications. It works by altering the actions of chemicals in your brain. Thorazine is used to treat psychotic disorders such as schizophrenia or manic-depression and severe behavioral problems in children aged between 1 to 12 years. Thorazine treats nausea and vomiting, anxiety before surgery, chronic hiccups, acute intermittent porphyria (metabolic disorder affecting the production of heme) and symptoms of tetanus (bacterial infection that causes muscle spasms and possibly lead to death).

Warnings Before Thorazine Treatment

You should not use this medicine if you have known allergies to Thorazine or other similar antipsychotics, and have recently used large amounts of alcohol, or taken a medicine that causes drowsiness.

Serious Side Effects

The FDA outlines the severe sides effects of Thorazine. Thorazine may increase the risk of death in elderly people who have dementia-related conditions.


It may also cause face and muscle twitching and uncontrollable movements, which all could be symptoms of tardive dyskinesia (a serious movement disorder that may be untreatable). Tardive dyskinesia is characterized by uncontrollable muscle movements of the lips, tongue, eyes, face, arms,and legs. The chance of developing this disorder is higher if thorazine is consumed in high doses and for long duration in women and older adults. Thorazine may also increase the risk of Neuroleptic Malignant Syndrome (NMS). NMS is a life-threatening hypersensitive reaction to antipsychotic drugs. This is characterized by: high fever, stiff muscles, confusion, sweating, changes in pulse, heart rate, and blood pressure. If these symptoms are experienced, Thorazine treatment should be stopped and immediately contact healthcare provider.


Additionally, Thorazine may cause muscle and nervous system problems (extrapyramidal symptoms or EPS). The FDA recommends notifying a doctor or healthcare provider if these symptoms occur:


  • Anxiety/agitation/jitteriness
  • Drooling or trouble swallowing
  • Restlessness/constant need to move
  • Shaking (tremor)
  • Shuffling walk
  • Stiff muscles
  • Severe muscle spasms or cramping (such as twisting neck, arching back, eyes rolling up)
  • Mask-like expression on the face


In rare cases, Thorazine may increase level of a certain chemical made by the body (prolactin). The side effects are different in females and males. For females there may be unwanted breast milk, missed or stopped periods, or difficulty in becoming pregnant. In males, Thorazine’s effects may be: decreased sexual ability, inability to produce sperm, have a painful or prolonged erection lasting 4 or more hours, or enlarged breasts. If these symptoms happen, tell a doctor right away.


If Thorazine is taken during the last 3 months of pregnancy, serious problems, such as withdrawal symptoms, breathing problems, feeding problems, tremors, and limp or stiff muscles may occur in the newborn. If you become pregnant while taking Thorazine, do not stop taking it without consulting your healthcare provider as you may experience withdrawal symptoms or other problems if you stop taking it. You should not breast-feed while using this medicine because it can pass into breast milk and may harm a nursing baby.

Common Side Effects

Common side effects of Thorazine include drowsiness, breast swelling or discharge, changes in menstrual periods, dry mouth or stuffy nose, blurred vision, constipation, and impotence, inability to achieve an erection (Thorazine label reported by the FDA).

When to Contact Your Doctor:

The FDA advises to call a doctor immediately if the following symptoms occur:


  • Uncontrolled muscle movements in the face (chewing, lip smacking, tongue movement, frowning, blinking or eye movement)
  • Tightness in the throat or sore throat
  • Trouble breathing or painful swallowing
  • Confusion
  • Sudden weakness or ill feeling
  • Fever or cold and flu symptoms
  • Stiffness in the neck
  • Chills
  • Painful mouth sores
  • Swollen gums
  • Skin sores
  • Cough
  • Pale skin
  • Easy bruising or bleeding
  • Jaundice (yellowing of the skin or eyes)


In addition, notify the doctor of severe nervous system reactions: very stiff or rigid muscles, sweating, fast or uneven heartbeats, tremors, or feeling like you might pass out.

Precautions While Taking Thorazine

Be careful if driving or anything that requires alertness as Thorazine may impair thinking or reactions. Avoid getting up too fast from a sitting or lying position, or dizziness may occur. Avoid drinking alcohol. Alcohol can increase some of the side effects of Thorazine. Avoid exposure to sunlight or tanning beds. Thorazine causes sunburn easily so wear protective clothing and use sunscreen when you are outdoors.

About Pharmacogenetic Testing

Thorazine is metabolized by the gene polymorphism CYP2D6. Some patients cannot undergo Thorazine treatment because of how he or she metabolizes the drug. Certain individuals may metabolize it slowly, resulting in adverse drug reactions while others may metabolize it faster making Thorazine ineffective. Those with low CYP2D6 activity do not metabolize Thorazine well making them more prone to the harmful effects of it. Pharmacogenetic testing has a potential value in identifying individuals with low CYP2D6 activity by the healthcare provider and preventing severe side effects.

Know Your Genetic Risk with the Rxight® Genetic Test

Rxight® anlayzes how you metabolize Thorazine and over 200 other prescription and over-the-counter (OTC) medications. This is all done with a simple cheek swab of your DNA, which lays the foundation of personalized and accurate medicine all based on your genetic profile. With your Rxight® results, your pharmacist will be able to see what medications are safe, harmful, and ineffective to you and will be able to apply this information into a successful treatment plan.


Know more about Rxight® by calling at 1-888-888-1932 or sending us an email at support@Rxight.com.


Contributors to this Article:
Michael Sapko, MD, PhD; and Deborah Kallick, PhD, Medicinal Chemistry

Read more about Rxight® : What Is PGx Testing?