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Thioridazine (By mouth)

Thioridazine (thye-oh-RID-a-zeen)

Treats the symptoms of schizophrenia.

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have had an allergic reaction to thioridazine, if you have a history of heart rhythm problems or extreme high or low blood pressure, or if you have a genetic defect involving an enzyme called cytochrome P450. You should not take thioridazine if you are also taking medicines for depression (such as amitriptyline, Paxil®, Prozac®, Zoloft®), blood pressure medicine (such as atenolol, metoprolol, propranolol), medicines for heart rhythm problems, or other antipsychotic medicines (Haldol®, Risperdal®). There are many other medicines, including over-the-counter medicines, that you should not use while you are taking thioridazine. Make sure your doctor knows about all other medicines you are using.

How to Use This Medicine:

Tablet, Liquid

  • Your doctor will tell you how much of this medicine to take and how often. Your dose may need to be changed several times in order to find out the what works best for you. Do not take more medicine or take it more often than your doctor tells you to.
  • Measure the oral liquid medicine with a marked measuring spoon or medicine cup, or use the dropper that came with the medicine.
  • You may mix the oral liquid concentrate with a half glass of distilled water or orange juice. Mix only enough medicine for one dose and drink all the liquid right away.

If a dose is missed:

  • If you miss a dose or forget to take your medicine, take it as soon as you can. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose.
  • Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine at room temperature in a closed container, away from heat, moisture, and direct light. Do not freeze.
  • Keep all medicine out of the reach of children and never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Certain drugs should not be used while using thioridazine. Using these drugs can cause very serious medical problems, heart problems, or even death.
  • Avoid drinking alcohol.
  • Make sure your doctor knows if you are using any medicines that make you sleepy (such as sleeping pills, cold and allergy medicine, narcotic pain killers, or sedatives).

Warnings While Using This Medicine:

  • If you are pregnant or breast feeding, talk to your doctor before taking this medicine. False positive (incorrect) pregnancy tests have been reported in patients taking this medicine.
  • Check with your doctor before taking thioridazine if you have an unusually slow heartbeat, low levels of potassium in your blood, seizures, or heart disease, or if you have ever had breast cancer. Also, tell your doctor if you have ever had a reaction to similar medicines, such as Thorazine® or Trilafon®.
  • Thioridazine can make some people feel dizzy or drowsy. Be careful if driving a car or operating machinery.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Dizziness, fainting
  • Fever, severe muscle stiffness, excessive sweating
  • Irregular or fast heartbeat
  • Muscle spasms of the neck, face, or tongue, or other body movements you cannot control
  • Severe chest pain
  • Trouble breathing
  • Unusual bleeding or bruising, seizures (convulsions)

If you notice these less serious side effects, talk with your doctor:

  • Changes in menstrual cycle
  • Changes in vision, such as trouble focusing, changes in how you see colors, or trouble seeing at night
  • Dry mouth
  • Lightheadedness, especially when standing up
  • Nausea, vomiting, diarrhea, or constipation
  • Sleepiness
  • Tremors or shaking

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088


Last Updated: 7/4/2014


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