Thioridazine - oral

Patient Medicine Information
Why do I need this medicine?
Thioridazine is used to treat schizophrenia (an illness that causes changes in perception, thoughts and behaviour) in patients who did not respond to previous therapy. It helps relieve symptoms common in schizophrenia, such as distorted thinking and emotional instability.
How do I take this medicine?
Take Thioridazine exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.

Take it together with food or immediately after a meal. Try to take it at the same time each day.

The dose of this medicine will be decided by your doctor. Your doctor will advise you on the treatment timeframe depending on the severity of your condition.

Thioridazine must be taken regularly for it to be effective. Continue taking Thioridazine even when you feel better. Do not stop taking it suddenly as this may worsen your condition.
What should I do if I have forgotten to take this medicine?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.

DO NOT double a dose under any circumstances.

If you often forget to take your medicine, let your doctor and pharmacist know.
When should I not use this medicine?
Alert your doctor if you have the following conditions:
  • severely low or high blood pressure
  • heart disease
  • genetic trait that causes reduced CYP2D6 activity
as Thioridazine may not be suitable for you.

Do not take Thioridazine with medicines used to treat depression, high blood pressure, or irregular heartbeat. Please see the section “Can I take this with other medicines?” below for more information.
What should I take note of while taking this medicine?
Inform your doctor if you have the following conditions:
  • paralytic ileus (bowel obstruction caused by slow movement or paralysis of the intestines)
  • inability to completely empty the bladder when urinating
  • dry mouth
  • enlarged prostate
  • visual problems
  • Parkinson’s disease (a disorder that affects the movement of a person, causing symptoms such as tremors, muscle stiffness, slowed movement and impaired balance or walking)
  • Alzheimer’s disease (a progressive disease which destroys memory and other important mental functions)
  • fits or seizure
  • liver disease
  • kidney disease
  • history of low white blood cell count caused by drug use
Let your doctor know if you are pregnant or breastfeeding.

Thioridazine may affect the ability of your body to adjust to temperature changes in the environment. Avoid exposure to very cold or very hot environments. Avoid strenuous exercise and activities like going to the sauna. Drink more water to prevent dehydration.

Thioridazine may affect the results of drug tests (e.g. detection of methadone and phencyclidine). If you are scheduled for a test, inform the laboratory personnel that you are taking this medicine.

Why is it important to keep my appointments with the doctor?

Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
  • Routine tests (e.g. ECG, liver function; cholesterol, sugar and electrolyte levels; blood count, eye examination) may be done while you are being treated with this medicine.
  • Regular monitoring of changes in vision, weight and height, and signs of involuntary movements may also be needed.
Your doctor will advise you about how often you need to have these tests.
What side effects could I experience?
Thioridazine may cause drowsiness and visual disturbances. If affected, do not drive or take part in any activity in which you need to be alert or need to see clearly.

This medicine may cause your blood pressure to fall suddenly when you get up from a sitting or lying down position and you may feel giddy. To minimise this problem, stand up slowly.

Other side effects may include any of the following: diarrhoea, constipation, nausea, vomiting, confusion, headache, nasal congestion, dry mouth, problems passing urine, rash, itching, weight gain, and difficulty sleeping.

Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
  • abnormal or fast heartbeat, chest pain
  • fever, muscle stiffness or cramps, excessive sweating
  • fever with persistent sore throats and mouth ulcers
  • fits or seizures
  • difficulty swallowing or speaking, irregular or jerky movements, slowness of movements
  • enlarged breasts, nipple discharge
  • changes in sex drive, menstrual changes
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Can I take this with other medicines?
Do not take Thioridazine if you are taking any of these medicines:
  • medicines to treat depression e.g. fluoxetine, paroxetine, fluvoxamine
  • medicines for high blood pressure e.g. propranolol, pindolol
  • medicines for irregular heartbeat e.g. disopyramide, procainamide
This list does not include all medicines that may interact with Thioridazine.

Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
What special dietary instructions should I follow?
Avoid alcohol. Alcohol intake may worsen the drowsiness caused by Thioridazine.
How should I store this medicine?
Store in a cool, dry place away from the reach of children.

Medicines must not be used past the expiry date.
This information is independently developed by MIMS based on thioridazine - oral and is provided for your reference only. It is not a replacement for and should only be used in conjunction with full consultation with a licensed healthcare professional, the information provided by your pharmacist and/or the manufacturer of the medication. It may not contain all the available information you require and cannot substitute professional medical care, nor does it take into account all individual circumstances. Although great effort has been made to ensure content accuracy, we shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2023 MIMS. All rights reserved. Powered by
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