Generic Name: Thioridazine Brand Name(s): Generics only. No brands available.


What is Thioridazine used for?

Thioridazine is used to treat certain mental/mood disorders (e.g., schizophrenia). This medication helps you to think more clearly, feel less nervous, and take part in everyday life. It can also help prevent suicide in people likely to harm themselves and reduce aggression and the desire to hurt others. It can help decrease your negative thoughts and hallucinations. Thioridazine belongs to a class of drugs known as phenothiazines.

How should I take Thioridazine?

Take this medication by mouth with or without food, usually 2-4 times a day or as directed by your doctor.

Dosage is based on your medical condition and response to therapy. Once your condition improves and you are better for a while, your doctor may work with you to reduce your regular dose. This may be done over time. Do not stop your medication or lower your dose without talking with your doctor first. Some conditions may become worse when the drug is stopped abruptly. Your dose may need to be gradually reduced.

Use this medication regularly in order to get the most benefit from it. To help you remember, use it at the same time(s) each day.

Inform your doctor if your condition persists or worsens.

How do I store Thioridazine?

Thioridazine is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Thioridazine in the bathroom or the freezer. There may be different brands of Thioridazine that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Thioridazine down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Thioridazine?

Before taking thioridazine, tell your doctor or pharmacist if you are allergic to it; or to other phenothiazines (e.g., chlorpromazine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: a certain severe nervous system problem (severe CNS depression), severe blood pressure problems.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: certain blood problems (e.g., low white blood cell count), Parkinson’s disease, history of seizures, low enzymes needed to remove drugs from the body (slow hydroxylator).

Thioridazine may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.

The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using thioridazine, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death).

Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/”water pills”) or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using thioridazine safely.

This drug may make you dizzy or drowsy. Alcohol or marijuana can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana.

Before having surgery, tell your doctor or dentist that you are taking this medication.

This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.

Older adults may be more sensitive to the side effects of this drug, especially dizziness, lightheadedness, drowsiness, confusion, constipation, difficulty urinating, and QT prolongation. Dizziness, lightheadedness, drowsiness, and confusion can increase the risk of falling.

During pregnancy, this medication should be used only when clearly needed. Babies born to mothers who have used this drug during the last 3 months of pregnancy may rarely develop symptoms including muscle stiffness or shakiness, drowsiness, feeding/breathing difficulties, or constant crying. If you notice any of these symptoms in your newborn especially during their first month, tell the doctor right away.

Since untreated mental/mood problems (such as schizophrenia, depression) can be a serious condition, do not stop taking this medication unless directed by your doctor. If you are planning pregnancy, become pregnant, or think you may be pregnant, immediately discuss with your doctor the benefits and risks of using this medication during pregnancy.

It is not known whether this drug passes into breast milk. Consult your doctor before breast-feeding.

Is it safe during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this Thioridazine during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking Thioridazine. Thioridazine is pregnancy risk category N according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown

Side effects

What side effects can occur from Thioridazine?

Dizziness, lightheadedness, drowsiness, difficulty urinating, constipation, restlessness, headache, and blurred vision may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

Dizziness and lightheadedness can increase the risk of falling. Get up slowly when rising from a sitting or lying position.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor if any of these serious side effects occur: shakiness (tremors), mask-like facial expression, jerking movements while walking.

Thioridazine may rarely cause a condition known as tardive dyskinesia. In some cases this condition may be permanent. Tell your doctor right away if you develop any unusual/uncontrolled movements (especially of the face, lips, tongue, arms or legs).

In rare cases, thioridazine may increase your level of a certain chemical made by the body (prolactin). For females, this increase in prolactin may result in unwanted breast milk, missed/stopped periods, or difficulty becoming pregnant. For males, it may result in decreased sexual ability, inability to produce sperm, or enlarged breasts. If you develop any of these symptoms, tell your doctor right away.

Tell your doctor right away if any of these rare but very serious side effects occur: signs of infection (e.g., fever, persistent sore throat), vision changes (e.g., vision loss, sudden difficulty seeing at night, brown-tinged vision).

Seek immediate medical attention if any of these rare but very serious side effects occur: severe dizziness, fainting, slow heartbeat, seizures.

This medication may rarely cause a very serious condition called neuroleptic malignant syndrome (NMS). Get medical help right away if you have any of the following symptoms: fever, muscle stiffness/pain/tenderness/weakness, severe tiredness, severe confusion, sweating, fast/irregular heartbeat, dark urine, signs of kidney problems (such as change in the amount of urine).

A very serious allergic reaction to this drug is unlikely. Seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.


What drugs may interact with Thioridazine?

Some products that may interact with this drug include: anticholinergic medications (e.g., belladonna alkaloids, atropine, scopolamine), cabergoline, cisapride, duloxetine, guanethidine, guanadrel, lithium, mirabegron, medications for Parkinson’s disease (e.g., levodopa, benztropine), pergolide, pindolol, propranolol, rolapitant, terbinafine, certain SSRI antidepressants (e.g., fluoxetine, fluvoxamine, paroxetine).

Many drugs besides thioridazine may affect the heart rhythm (QT prolongation), including amiodarone, dofetilide, pimozide, procainamide, quinidine, sotalol, macrolide antibiotics (such as erythromycin), among others. Therefore, before using thioridazine, report all medications you are currently using to your doctor or pharmacist.

Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana, drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine).

Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

Thioridazine may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with Thioridazine?

Thioridazine may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Thioridazine?

Thioridazine may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.


The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Thioridazine.

What is the dose of Thioridazine for an adult?

Usual Adult Dose for Schizophrenia

Initial dose: 50 to 100 mg orally 3 times a day

Maintenance dose: 200 to 800 mg/day, divided into 2 to 4 doses

Maximum dose: 800 mg/day


-Once control is attained, the dose should be gradually lowered to determine the minimum effective maintenance dose.

Use: Patients with schizophrenia who failed to respond to treatment with other antipsychotic agents

Dose Adjustments

Patients at risk of QT Prolongation and/or CYP450 2D6 poor metabolizers:

-QT interval greater than 450 msec at baseline: Not recommended

-QT interval greater than 500 msec during treatment: Discontinue use

Other Comments

Administration advice:

-See manufacturer product information.

Storage requirements:

-See manufacturer product information.


-Safety and efficacy of treatment in patients for refractory schizophrenia is not known.

-Use should be limited to patients who have failed treatment with other antipsychotic drugs.

-The lowest effective dose should be used due to a dose-related risk of QT prolongation, arrhythmia, and death.


-ECGs, especially before starting treatment, during dose adjustments, and periodically thereafter

-Potassium, especially before starting treatment and periodically thereafter

-Periodic WBC with differential tests, especially in patients with signs/symptoms of infection/sore throat or with a history of low WBCs or drug-induced neutropenia/leukopenia

-Eye examinations, especially in patients on prolonged treatment

-Periodic electrolyte levels, especially in patients with a high risk of developing cardiovascular events and/or those taking diuretics

Patient advice:

-Warn patients to avoid abrupt discontinuation of this drug.

-Tell patients to immediately report any signs/symptoms of neutropenia/leukopenia, neuroleptic malignant syndrome, tardive dyskinesia, or Torsades de pointes.

-Advise patients, and families/caregivers to monitor and report signs/symptoms of unusual behavior immediately to their healthcare provider (e.g., agitation, irritability, anxiety, panic attacks, insomnia, hostility, aggressiveness, impulsivity, akathisia, hypomania/mania).

-Patients should be advised to report all concurrent prescription and nonprescription medications or herbal products they are taking.

-Patients should be instructed to speak to a healthcare provider if they are pregnant, intend to become pregnant, or are breastfeeding.

-Inform patients that this drug may cause drowsiness, and they should avoid driving or operating machinery until the full effects of the drug are seen.

What is the dose of Thioridazine for a child?

Usual Pediatric Dose for Schizophrenia

Initial dose: 0.5 mg/kg/day orally, in divided doses

Maximum dose: 3 mg/kg/day, in divided doses


-The dose should be increased gradually until therapeutic effects are observed and/or the maximum dose is reached.

Use: Patients with schizophrenia who have failed to respond to treatment with other antipsychotic agents

How is Thioridazine available?

Thioridazine is available in the following dosage forms and strengths:

  • Oral concentrate,
  • Oral tablet,
  • Oral suspension.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Thioridazine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.


Review Date: May 10, 2018 | Last Modified: May 10, 2018

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