Perphenazine - oral

Patient Medicine Information
Why do I need this medicine?
Perphenazine is used to treat schizophrenia (a long-term mental disorder that causes changes in thoughts, feelings, and behaviour). It helps to relieve symptoms common in schizophrenia, such as distorted thinking and emotional instability.

This medicine may also be used to relieve severe nausea and vomiting.

Perphenazine may be used to treat other conditions as decided by your doctor.
How do I take this medicine?
Take Perphenazine 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.

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 type and severity of your condition.

If you are taking Perphenazine for schizophrenia, it must be taken regularly for it to be effective. Continue taking this medicine even when you feel well. 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:
  • liver damage
  • bone marrow depression (a condition in which the blood cells are low)
  • brain damage or disorders
  • blood disorders
as Perphenazine may not be suitable for you.

Do not take this medicine if you are taking large doses of medicines that can cause drowsiness or affect your concentration, such as phenobarbital.
What should I take note of while taking this medicine?
Inform your doctor if you have the following conditions:
  • heart disease
  • lung disease
  • fits or seizures
  • depression
  • history of low white blood cell count caused by drug use
  • Alzheimer’s disease (a progressive disease which destroys memory and other important mental functions)
  • exposed to extreme heat or phosphorus insecticides
  • undergoing strenuous exercise
  • enlarged prostate gland
  • kidney disease
  • liver disease
Let your doctor know if you are pregnant or breastfeeding.

Be sure to check with your doctor or pharmacist before giving this medicine to the elderly. Elderly people may be more sensitive to the side effects.

A certain enzyme called CYP2D6 is involved in the breakdown of Perphenazine in the body. Individuals who are known as poor metabolisers of CYP2D6 may experience enhanced side effects of this medicine. If you know you have this gene type, inform your doctor.

If you are going to have an operation, including minor surgery and dental work, inform your doctor or dentist 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. liver/kidney function, cholesterol/sugar/electrolyte levels, eye examination, complete blood count) may be needed while you are being treated with Perphenazine. Your doctor will advise you about how often you need to have these tests.
  • Regular monitoring of mental status and changes in vision may also be needed.
What lifestyle changes should I make?

This medicine 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.
What side effects could I experience?
Perphenazine may cause drowsiness or some problems with your eyesight, such as blurred vision. 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.

It may also make your skin more sensitive to sunlight. Apply sunscreen when going outdoors and avoid prolonged exposure to sunlight and UV lamps.

Other side effects include any of the following: blocked nose, dry mouth, nausea, vomiting, diarrhoea, constipation, loss of appetite, difficulty urinating or frequent urination, and skin pigmentation.

Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
  • very high fever, muscle rigidity, excessive sweating, and mental status changes
  • mood changes, difficulty speaking or swallowing, irregular or jerky movements
  • yellowing of the skin or eyes, stomach pain, persistent tiredness, dark coloured urine, swelling in the legs and ankles
  • irregular heartbeat, chest pain
  • fits or seizures
Perphenazine may cause the level of your red blood cells, white blood cells and platelets to drop.

Red blood cells carry oxygen around your body. A fall in the level of red blood cells may make you feel tired and worn out.

White blood cells help your body to fight infections. A fall in the level of your white blood cells may put you at higher risk for infections, such as coughs, colds and flu, which may lead to more serious infections. Avoid crowded places and people who are sick. Inform your doctor if you have a fever, or a cough or flu that does not go away.

Platelets help your blood to clot when there is a cut in the skin. A fall in the level of your platelets may put you at risk of bleeding more than usual. Do not take part in activities where you may fall or get injured, such as contact sports. Inform your doctor if you get any unusual bruising (large bruises or several bruises, especially if the bruises appeared on their own) or bleeding that takes a long time to stop (for example, too much bleeding when you floss or brush your teeth).

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 Perphenazine if you are taking large doses of any of these medicines:
  • medicines for epilepsy (fits or seizures) e.g. phenobarbital
  • strong painkillers e.g. morphine
  • medicines for cold or allergy e.g. diphenhydramine
Inform your doctor and pharmacist if you are taking medicines to treat depression e.g. amitriptyline, fluoxetine.

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.
How should I store this medicine?
Store in a cool, dry place away from the reach of children.

Protect from light.

Medicines must not be used past the expiry date.
This information is independently developed by MIMS based on perphenazine - 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 © 2021 MIMS. All rights reserved. Powered by
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