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Procysbi 300 mg gastro-resistant granules – patient leaflet, side effects, dosage

Text from the MHRA, as of · About this document

Medicine status: Prescription only (POM) Details

Medicine strength:
300 mg
Contains active substance:
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Patient leaflet - Procysbi 300 mg gastro-resistant granules

1. What PROCYSBI is and what it is used for

PROCYSBI contains the active substance cysteamine (also known as mercaptamine) and is taken for the treatment of nephropathic cystinosis in children and adults. Cystinosis is a disease affecting how the body functions, with an abnormal accumulation of the amino acid cystine in various organs of the body such as the kidney, eye, muscle, pancreas, and brain. Cystine build-up causes kidney damage and excretion of excess amounts of glucose, proteins, and electrolytes. Different organs are affected at different ages.

PROCYSBI is a medicine that reacts with cystine to decrease its level within the cells. Cysteamine therapy should be initiated promptly after confirmation of the diagnosis of cystinosis to achieve maximum benefit.

2. What you need to know before you take PROCYSBI

Do not take PROCYSBI

  • If you are allergic to cysteamine (also known as mercaptamine) or any of the other ingredients of this medicine (listed in section 6).
  • If you are allergic to penicillamine (this is not “penicillin”, but a medicine used for the treatment of Wilson’s disease).
  • If you are breast-feeding.

Warnings and precautions

Talk to your doctor or pharmacist before taking PROCYSBI.

  • Since oral cysteamine doesn’t prevent deposits of cystine crystals in the eye, you should continue taking cysteamine eye drops as prescribed by your doctor.
  • Serious skin lesions can occur in patients treated with high doses of cysteamine. Your doctor will routinely monitor your skin and bones and reduce or stop your treatment if needed (see section 4).
  • Stomach and intestinal ulcers and bleeding can occur in patients receiving cysteamine (see section 4).
  • Other intestinal symptoms including nausea, vomiting, anorexia and stomach ache can occur with cysteamine. Your doctor may interrupt and change your dose if these occur. − Talk to your doctor if you have any unusual stomach symptoms or changes in stomach symptoms.
  • Symptoms such as seizures, tiredness, sleepiness, depression, and brain disorders

    (encephalopathy) can occur with cysteamine. If such symptoms develop, tell your doctor who will adjust your dose.

  • Abnormal liver function or reduced white blood cell count (leukopenia) can occur with use of cysteamine. Your doctor will routinely monitor your blood counts and liver function. − Your doctor will monitor you for benign intracranial hypertension (or pseudotumor cerebri

    [PTC]) and/or swelling of the optic nerve (papilledema) associated with cysteamine treatment. You will receive regular eye examinations to identify this condition as early treatment can prevent vision loss.

Other medicines and PROCYSBI

Tell your doctor or pharmacist if you are taking, have recently taken, or might take any other medicines. If your doctor prescribes bicarbonate, do not take it at the same time as PROCYSBI; take bicarbonate at least one hour before or at least one hour after the medicine.

PROCYSBI with food and drink

For at least 1 hour before and 1 hour after taking PROCYSBI try to avoid meals, which are rich in fat or proteins as well as any food or liquid that could decrease the acidity in your stomach, like milk or yogurt. If this is not possible, you can eat a small amount (about 100 grams) of food (preferably carbohydrates e.g. bread, pasta, fruits) during the hour before and after taking PROCYSBI. See also section 3 “How to take PROCYSBI - Method of Administration”.

Pregnancy and breastfeeding

If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.

You should not use this medicine if you are pregnant, particularly during the first trimester. Before starting the treatment, you should have a pregnancy test with negative result, while during the course of treatment you should use an adequate method of contraception. If you are a woman planning a pregnancy or become pregnant, seek immediate advice from your doctor about stopping therapy with this medicine as continued treatment may be harmful to the unborn baby.

Do not use this medicine if you are breastfeeding (see section 2 under “Do not take PROCYSBI”).

Driving and using machines

This medicine may cause some drowsiness. When starting therapy, you should not drive, use machines, or engage in other dangerous activities until you know how the medicine affects you.

PROCYSBI contains sodium

This medicine contains less than 1 mmol sodium (23 mg) per dose, that is to say essentially “sodium-free.”

3. How to take PROCYSBI

Always take this medicine exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure.

The recommended dose for you or your child will depend on your or your child’s age and weight. The targeted maintenance dose is 1.3 g/m2/day.

Dosing schedule

Take this medicine two times a day, every 12 hours. To get the most benefit from this medicine, try to avoid meals and dairy products for at least 1 hour before and 1 hour after PROCYSBI dosing. If this is not possible, you can eat a small amount (about 100 grams) of food (preferably carbohydrates e.g. bread, pasta, fruits) during the hour before and after PROCYSBI administration.

It is important to take PROCYSBI in a consistent way over time.

Do not increase or decrease the amount of medicine without your doctor’s approval.

The total usual dose should not exceed 1.95 g/m2/day.

Duration of treatment

Treatment with PROCYSBI should continue life-long, as instructed by your doctor.

Method of administration

You should take this medicine only by mouth.

Each sachet has to be used only once.

In order for this medicine to work correctly, you must do the following:

Open the sachet and sprinkle all granules on food (such as apple sauce or fruit jam) and eat or administer through feeding tubes or mixed with an acidic drink (such as orange juice or any acidic juice) or water and drink. Do not crush or chew granules.

Sprinkling on food

Open the sachet and sprinkle all granules onto approximately 100 grams of food such as apple sauce or fruit jam. Gently stir the granules into the soft food, creating a mixture of granules and food. Eat the entire mixture. Then drink about 250 mL of an acidic drink (such as orange juice or any acidic fruit juice) or water to ease the swallowing of the mixture.

If you don’t eat the mixture immediately, you may refrigerate (2°C-8°C) it from the time of preparation to the time of administration and eat it within 2 hours of preparation. Nothing of the mixture should be saved beyond 2 hours.

Administering through feeding tube

Open the sachet and sprinkle the granules onto approximately 100 grams of apple sauce or fruit jam. Gently stir the granules into the soft food, creating a mixture of granules and the soft food. Administer the mixture by gastrostomy tube, nasogastric tube or gastrostomy jejunostomy tube using a catheter tip syringe. Before PROCYSBI administration: Unclasp the G-tube button and attach the feeding tube. Flush with 5 mL of water to clear the button. Draw the mixture up into the syringe. A maximum 60 mL mixture volume in a catheter tip syringe is recommended for use with a straight or bolus feeding tube. Place the opening of the syringe containing the PROCYSBI and food mixture into the opening of the feeding tube and fill completely with the mixture: pressing gently on the syringe and keeping the feeding tube horizontal during administration can help to avoid clogging issues. Using a viscous food such as apple sauce or fruit jam at a rate of about 10 mL every 10 seconds until the syringe is completely empty is suggested to avoid clogging. Repeat the above step until all of the mixture is given. After PROCYSBI administration, draw 10 mL of fruit juice or water up into another syringe and flush the G-tube ensuring that none of the PROCYSBI and food mixture gets stuck in the G-tube. If you don’t consume the mixture immediately, you may refrigerate (2°C-8°C) it from the time of preparation to the time of administration and consume it within 2 hours of preparation. Nothing of the mixture should be saved beyond 2 hours.

Consult your child’s doctor for complete instructions on how to properly administer the product through feeding tubes and if you experience clogging issues.

Sprinkling in orange juice or any acidic fruit juice or water

Open the sachet and sprinkle the granules into about 100 to 150 mL of acidic fruit juice (such as orange juice or any acidic juice) or water. Mix the PROCYSBI drink mixture gently for 5 minutes, either mixing in a cup or shaking in a covered cup (e.g., “sippy” cup) and drink the mixture.

If you don’t drink the mixture immediately, you may refrigerate (2°C-8°C) it from the time of preparation to the time of administration and drink it within 30 minutes after preparation. Nothing of the mixture should be saved beyond 30 minutes.

Administering a drink mixture by oral syringe

Aspirate the drink mixture into a dosing syringe and administer it into the mouth directly. If you don’t consume the mixture immediately, you may refrigerate (2°C-8°C) it from the time of preparation to the time of administration and consume it within 30 minutes after preparation. Nothing of the mixture should be saved beyond 30 minutes.

Your doctor may recommend or prescribe to include, in addition to cysteamine, one or more supplements to replace important electrolytes lost through the kidneys. It is important to take these supplements exactly as instructed. If several doses of the supplements are missed or weakness or drowsiness develops, call your doctor for instructions.

Regular blood tests to measure the amount of cystine inside white blood cells and/or the concentration of cysteamine in the blood are necessary to help determine the correct dose of PROCYSBI. You or your doctor will arrange for these blood tests to be performed. These tests must be obtained 12.5 hours after the evening dose the day before, and therefore 30 minutes after the following morning dose is given. Regular blood and urine tests to measure the levels of the body’s important electrolytes are also necessary to help you or your doctor correctly adjust the doses of these supplements.

If you take more PROCYSBI than you should

You should contact your doctor or the hospital emergency department immediately if you have taken more PROCYSBI than you should. You may become drowsy.

If you forget to take PROCYSBI

If you missed a dose of medicine, you should take it as soon as possible. However, if it is within 4 hours of the next dose, skip the missed dose and go back to the regular dosing schedule.

Do not take a double dose to make up for a forgotten dose.

If you have any further questions on the use of this medicine, ask your doctor or pharmacist.

4. Possible side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them.

Tell your doctor or nurse straight away if you notice any of the following side effects – you may need urgent medical treatment:

  • Severe allergic reaction (seen uncommonly): Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of face, lips, tongue, or throat.

If any of the following side effects occur, please contact your doctor immediately. Since some of these side effects are serious, ask your doctor to explain their warning signs.

Common side effects (may affect up to 1 in 10 people):

  • Skin rash: Tell the doctor right away if you get a skin rash. PROCYSBI may need to be temporarily stopped until the rash goes away. If the rash is severe, your doctor may discontinue cysteamine treatment.
  • Abnormal liver function on blood tests. Your doctor will monitor you for this. Uncommon side effects (may affect up to 1 in 100 people):
  • Skin lesions, bone lesions, and joint problems: Treatment with high doses of cysteamine can cause skin lesions to develop. These include skin striae (which are like stretch marks), bone injuries (such as fractures), bone deformities, and joint problems. Examine your skin while taking this medicine. Report any changes to your doctor. Your doctor will monitor you for these problems.
  • Low white blood cell count. Your doctor will monitor you for this.
  • Central nervous system symptoms: Some patients taking cysteamine have developed seizures, depression, and become too sleepy (excessive sleepiness). Tell your doctor if you have these symptoms.
  • Stomach and intestinal (gastrointestinal) problems: Patients taking cysteamine have developed ulcers and bleeding. Tell your doctor right away if you get stomach ache, or throw up blood. − Benign intracranial hypertension, also called pseudotumor cerebri, has been reported with cysteamine use. This is a condition where there is high pressure in the fluid around the brain. Tell your doctor right away if you develop any of the following symptoms while taking PROCYSBI: buzzing or “whooshing” sound in the ear, dizziness, double vision, blurry vision, loss of vision, pain behind the eye or pain with eye movement. Your doctor will monitor you with eye examinations to find and treat this problem early. This will help lessen the chance of loss of eyesight.

The other side effects listed below are given with an estimation of the frequency with which they may occur with PROCYSBI.

Very common side effects (may affect more than 1 in 10 people):

  • nausea
  • vomiting
  • loss of appetite
  • diarrhoea
  • fever
  • sensation of sleep

Common side effects:

  • headache
  • encephalopathy
  • abdominal pain
  • dyspepsia
  • unpleasant breath and body odour
  • heartburn
  • tiredness

Uncommon side effects:

  • leg pain
  • scoliosis (deviation of the vertebral column)
  • bone fragility
  • hair discolouration
  • fits
  • nervousness
  • hallucination
  • effect on the kidney manifested by swelling of the extremities and weight gain

Reporting of side effects

If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via:

Yellow Card Scheme, Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.

By reporting side effects you can help provide more information on the safety of this medicine.

5. How to store PROCYSBI

Keep this medicine out of the sight and reach of children.

Do not use this medicine after the expiry date, which is stated on the carton and the sachet after EXP. The expiry date refers to the last day of that month.

Store in a refrigerator (2°C-8°C). Do not freeze.

Keep the sachets in the outer carton in order to protect from light and moisture. Unopened sachets may be stored for a single period of up to 4 months outside the refrigerator at temperatures below 25°C. Thereafter, the medicine must be discarded.

Each sachet is for single use only.

Do not throw away any medicines via wastewater. Ask your pharmacist how to throw away the medicines you no longer use. These measures will help protect the environment.

6. Contents of the pack and other information

What PROCYSBI contains

  • The active substance is cysteamine (as mercaptamine bitartrate).

    PROCYSBI 75 mg gastro resistant granules

    Each sachet of gastro-resistant granules contains 75 mg of cysteamine.

    PROCYSBI 300 mg gastro resistant granules

    Each sachet of gastro resistant granules contains 300 mg of cysteamine.

  • The other ingredients are: microcrystalline cellulose, methacrylic acid - ethyl acrylate copolymer (1:1), hypromellose, talc, triethyl citrate, sodium lauryl sulfate (see section “PROCYSBI contains sodium”).

What PROCYSBI looks like and contents of the pack

  • PROCYSBI 75 mg is presented as white to off-white gastro-resistant granules in sachets. Each pack contains 120 sachets.
  • PROCYSBI 300 mg is presented as white to off-white gastro-resistant granules in sachets. Each pack contains 120 sachets.

Marketing Authorisation Holder

Chiesi Limited

333 Styal Road

Manchester

M22 5LG

United Kingdom

Manufacturer

Chiesi Farmaceutici S.p.A.

Via San Leonardo 96

43122 Parma

Italy

For any information about this medicine, please contact the local representative of the Marketing Authorisation Holder:

Great Britain

Chiesi Ltd

Tel: + 44 (0)161 488 5555

This leaflet was last revised in

Detailed information on this medicine is available on the website of the European Medicines Agency http://www.ema.europa.eu.

About this document

Source: MHRA - Medicines and Healthcare products Regulatory Agency (products.mhra.gov.uk) · Marketing authorisation: PLGB 08829/0206

MHRA data as of 13 October 2026

Found a mistake? Tell us on the contact page.

The information on this site does not replace the advice of a doctor or pharmacist.

Facts about Procysbi 300 mg gastro-resistant granules

Prescription needed? Yes, prescription-only medicine (POM)
Active substance Mercaptamine
Strength 300 mg
Pharmaceutical form White to off-white granules.
Excipients microcrystalline cellulose, methacrylic acid - ethyl acrylate copolymer (1:1), hypromellose, talc, triethyl citrate, sodium lauryl sulphate
Is it available? Listed as available (NHS Dictionary of Medicines and Devices – not a record of current supplies)
Shelf life 3 years
Unopened sachets may be stored for a single period of up to 4 months at temperatures below 25°C protected from light and moisture, after which the medicinal product must be discarded.
Storage Store in a refrigerator (2°C-8°C).
Do not freeze.
Keep the sachets in the outer carton in order to protect from light and moisture.
During the shelf-life, the medicinal product may be stored at room temperature (below 25°C) for a single period of 4 months (see section 6.3).
Drug group (ATC) Other alimentary tract and metabolism product, amino acids and derivatives
  1. A Alimentary tract and metabolism drugs
    1. A16 Other alimentary tract and metabolism products
      1. A16A Other alimentary tract and metabolism products
        1. A16AA Amino acids and derivatives
          1. A16AA04 mercaptamine
Marketing authorisation PLGB 08829/0206 (first authorised 11 August 2023)
Marketing authorisation holder Chiesi Limited

Sources: the MHRA product information (products.mhra.gov.uk) and the NHS Dictionary of Medicines and Devices (dm+d), release 10.2.0 of 19 October 2026, NHS Business Services Authority. Contains public sector information licensed under the Open Government Licence v3.0.