Flupenthixol Depot Injection

Medication Information Leaflet

What is this medication for?

Flupenthixol depot injection belongs to a class of medications known as typical (first-generation) antipsychotics. It is used to treat and prevent the return of symptoms in Schizophrenia and other mental health related conditions such as:

  • Hearing, seeing or sensing things that are not real

  • Having mistaken beliefs

  • Uncontrolled anger

  • Being overly suspicious

A depot injection is a special preparation of medication which is given in the form of an injection into the upper arm, thigh or buttocks. The medication is then slowly released and absorbed to the rest of the body over a number of weeks.

This medication may also be used for other conditions. Check with your healthcare professional if you are unsure why you are given this medication.

How should I take/use this medication?

  • A small dose of the medication, called a test dose, will usually be given when you are started on this medication to help avoid any prolonged and severe side effects.

  • If you have no side effects from the test dose, you may be given an additional dose, called a top-up dose, a few days or up to a week after the test dose.

  • Subsequent injections will be given at regular intervals. The interval between each injection will be decided by your doctor (e.g. every 2 to 4 weeks).

  • It is important for you to be regular with your scheduled depot injections at the clinic. Missing your injections for too long a time (e.g. several weeks or months) may result in a recurrence of your previous symptoms.

What should I do if I forget to take/use this medication?

If you have missed an injection, please call up your doctor to arrange for an appointment visit.

What precautions should I take?

Inform your healthcare professional if:

  • You are allergic to this medication or any of the other ingredients of this medication

  • You are pregnant, planning to become pregnant, or breastfeeding. If you are pregnant and/or breastfeeding, your doctor would have discussed the potential benefits and side effects with you and should you have further questions or concerns, do consult your doctor.

  • You are taking any other medications including those that can be bought without a prescription, supplements, traditional Chinese medicine and herbal remedies. Some of them may affect how this medication works or cause serious drug interactions.

  • You have or have ever had:

    • Other drug allergies

    • Medical conditions such as:

      • Heart or liver disease, urinary problems, stroke

      • Parkinson’s disease, dementia, seizure (fits), irregular heartbeat, low blood pressure, blood disorders, diabetes, venous thromboembolism (formation of a blood clot in the veins which may travel to other parts of the body)

Flupenthixol depot injection can make your skin more sensitive to sunlight. Avoid prolonged exposure to sunlight. Wear protective clothing or use sunscreen if necessary.

What are some common side-effects of this medication?

The mentioned side effects generally affect up to 10% of patients.

  • Constipation

    • Drink more water (if not on fluid-restricted diet), eat more high-fibre foods and exercise regularly

    • Speak to your doctor or pharmacist if you need a medication to help with your constipation

  • Light-headedness (especially during a sudden change in posture)

    • Get up slowly from a sitting or lying down position

  • Feeling tired or drowsy

    • Avoid driving or engaging in activities requiring concentration

  • Increase in appetite, weight gain

    • Observe healthy dietary habits and exercise regularly

  • Dry mouth

    • Chew sugar-free gum, suck on sugar-free hard candies or ice chips, sip water regularly

  • Muscle movement side effects (extrapyramidal side effects):

    • Muscle stiffness and spasms (such as in the face, neck and back), difficulty in speaking or swallowing, twitching, or upward rolling of eyes (dystonia)

    • Restlessness or need to keep moving constantly (akathisia)

    • Involuntary shaking of limbs (tremors)

    • Speak to your doctor for further management of the above

  • Pain at injection site

Most of the side effects listed here will improve with time. Speak to your doctor if they continue, get worse or are affecting your daily life.

What are some rare but serious side-effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following:

  • Swollen face/eyes/lips/tongue

  • Difficulty in breathing

  • Itchy skin rashes over your whole body

Rarely this medication may cause:

  • High fever, severe muscle stiffness, confusion, irregular blood pressure (signs and symptoms of neuroleptic malignant syndrome)

  • Uncontrollable movements (such as in the face, tongue, jaw or other parts of the body) (tardive dyskinesia)

  • Sudden weakness or numbness in the face, arms or legs, and speech or vision problems

  • Seizures (fits)

  • Problems with eyesight or blurred vision

  • Difficulty in passing urine (urinary retention)
  • Fast or irregular heartbeat, fainting episodes (signs and symptoms of an abnormal heart beating rhythm (prolonged QTc interval))
  • Fever, sore throat and/or mouth ulcers that do not go away (symptoms of blood dyscrasias)
  • Severe chest pain, difficulty breathing, or severe pain or swelling in either of the legs (symptoms of venous thromboembolism)
  • Increased prolactin hormone in the body (hyperprolactinemia):

    • Changes in menstrual cycle in females (Irregular or stopping of menstrual periods) and/or

    • Abnormal breast swelling, soreness or secretion (in both men and women)

If you experience any of these side effects, you should stop your medication and inform your healthcare professional immediately.

Please also take note that the above listed side effects are not exhaustive. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

What food or medication should I avoid when I take this medication?

Avoid drinking alcohol while taking this medication as it can cause excessive drowsiness.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

How should I throw away this medication safely?

Pack this medication into a black trash bag and seal it tightly before throwing into the rubbish chute or bin.


If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on Jun 2021

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