SUMMARY CMI

CYSTAGON^®

Consumer Medicine Information (CMI) summary

The full CMI on the next page has more details. If you are worried about taking this medicine, speak to your doctor or pharmacist.

1. Why am I taking CYSTAGON?

CYSTAGON contains the active ingredient mercaptamine (cysteamine) bitartrate. CYSTAGON is used to manage nephropathic cystinosis, in children and adults.
For more information, see Section 1. Why am I taking CYSTAGON? in the full CMI.

2. What should I know before I take CYSTAGON?

Do not take if you have ever had an allergic reaction to mercaptamine, penicillamine, or any of the ingredients listed at the end of the CMI.
Talk to your doctor if you have any other medical conditions, take any other medicines, or are pregnant or plan to become pregnant or are breastfeeding.
For more information, see Section 2. What should I know before I take CYSTAGON? in the full CMI.

3. What if I am taking other medicines?

Some medicines may interfere with CYSTAGON and affect how it works.

A list of these medicines is in Section 3. What if I am taking other medicines? in the full CMI.

4. How do I take CYSTAGON?

• The dose of CYSTAGON is based on your weight.

More instructions can be found in Section 4. How do I take CYSTAGON? in the full CMI.

5. What should I know while taking CYSTAGON?

For more information, see Section 5. What should I know while taking CYSTAGON? in the full CMI.

6. Are there any side effects?

Less serious side effects include nausea, vomiting, loss of appetite, diarrhoea, drowsiness, rash, unpleasant breath odour, fever or feel tired or fatigued.

Serious side effects include stomach pain, loss of appetite, throwing up blood, seizures, depression, excessive sleepiness, low white blood cell count, abnormal liver function headache, dizziness, double vision, blurry vision, loss of vision, pain behind the eye or pain with eye movement, skin lesions, bone lesions or joint problems.
Please note this is not a complete list of possible side effects.

For more information, including what to do if you have any side effects, see Section 6. Are there any side effects? in the full CMI.

FULL CMI

CYSTAGON^®

Active ingredient: mercaptamine (cysteamine) bitartrate

Consumer Medicine Information (CMI)

This leaflet provides important information about taking CYSTAGON. You should also speak to your doctor or pharmacist if you would like further information or if you have any concerns or questions about taking CYSTAGON.

Where to find information in this leaflet:

1. Why am I taking CYSTAGON?
2. What should I know before I take CYSTAGON?
3. What if I am taking other medicines?
4. How do I take CYSTAGON?
5. What should I know while taking CYSTAGON?
6. Are there any side effects?
7. Product details

1. Why am I taking CYSTAGON?

CYSTAGON contains the active ingredient mercaptamine (cysteamine).

CYSTAGON is used to manage nephropathic cystinosis, in children and adults.

Nephropathic cystinosis is a rare inherited disorder characterised by the build-up of cystine in organs such as kidneys. Cystine build up causes kidney damage and excretion of excess amounts of glucose, proteins and electrolytes.

Cystinosis can be detected by measuring the amount of cystine in while blood cells and other body cells. The results of cystinosis are slow body growth, weak bones and progressive kidney failure.

Mercaptamine (cysteamine) works by reacting with cystine so that the cystine level in cells is decreased.

Ask your doctor if you have any questions about why this medicine has been prescribed for you. Your doctor may have prescribed it for another reason.

2. What should I know before I take CYSTAGON?

Warnings

Do not take CYSTAGON if:

• you are allergic to mercaptamine, penicillamine, or any of the ingredients listed at the end of this leaflet.
  Some of the symptoms of an allergic reaction may include:
  - shortness of breath
  - wheezing or difficulty breathing
  - swelling of the face, lips, tongue or other parts of the body
  - rash, itching or hives on the skin.
  Always check the ingredients to make sure you can take this medicine.
• the expiry date printed on the pack has passed or if the packaging is torn or shows signs of tampering.

If you are not sure whether you should start taking this medicine, talk to your doctor.

Check with your doctor if you:

• have allergies to any other medicines, foods, preservatives or dyes
• take any medicines for any other condition
• have or have ever had any of the following medical conditions:
  - a skin rash or any bone problems
  - a history of seizures, exhaustion, depression or other nervous system problems
  - stomach or intestinal problems including ulcers or bleeding
  - blood problems.

If you have not told your doctor about any of the above, tell them before you start taking CYSTAGON.

During treatment, you may be at risk of developing certain side effects. It is important you understand these risks and how to monitor for them. See additional information under Section 6. Are there any side effects?

Pregnancy and breastfeeding

Tell your doctor if you are pregnant or plan to become pregnant or if you are breastfeeding or plan to breastfeed.

Your doctor can discuss with you the risks or benefits involved.

3. What if I am taking other medicines?

Tell your doctor or pharmacist if you are taking any other medicines, including any medicines, vitamins or supplements that you buy without a prescription from your pharmacy, supermarket or health food shop.

Tell your doctor or pharmacist if you are taking an electrolyte replacement supplement.

Replacement of electrolytes (like potassium) is still required during therapy with CYSTAGON capsules.

Your doctor or pharmacist will have more information on medicines to be careful with or avoid while taking this medicine.

Check with your doctor or pharmacist if you are not sure about what medicines, vitamins or supplements you are taking and if these affect CYSTAGON.

4. How do I take CYSTAGON?

Follow all directions given to you or your child by your doctor or pharmacist carefully. They may differ from the information contained in this leaflet.

How much to take

• The dose of CYSTAGON is based on your weight.
• The initial dose for both children and adults is 200 mg to 300 mg/m²/day given in four divided doses.
• This dose will increase over a period of 4 to 6 weeks as directed by your doctor to a maintenance dose:
  - for children up to 12 years: 1.3 g /m²/day.
  - for patients over 12 years and 50 kg body weight: 2 g/day.
• Do not give the whole CYSTAGON capsule to children under six years or age because they may not be able to swallow it and they may choke. For those who are unable to swallow the capsules whole, the capsule may be opened and the contents sprinkled on food or mixed in formula.
• Ask your doctor for full instructions.

When to take CYSTAGON

• Take CYSTAGON at about the same time each day.
  Taking it at the same time each day will have the best effect. It will also help you remember when to take it.

How long to take CYSTAGON

• Continue taking your medicine for as long as your doctor tells you.

If you forget to take CYSTAGON

If it is less than 2 hours before your next dose, skip the dose you missed and take your next dose when you are meant to.

Otherwise, take it as soon as you remember, and then go back to taking your medicine as you would normally.

Do not take a double dose to make up for the dose you missed.

If you are not sure what to do, ask your doctor or pharmacist.

If you have trouble remembering to take your medicine, ask your pharmacist for some hints.

If you take too much CYSTAGON

If you think that you or anyone else has taken too much CYSTAGON, urgent medical attention may be needed.

You should immediately:

• phone the Poisons Information Centre
  (Australia telephone 13 11 26) for advice, or
• contact your doctor, or
• go to the Emergency Department at your nearest hospital.

You should do this even if there are no signs of discomfort or poisoning.

Symptoms of an overdose may include vomiting, dehydration, feeling of tiredness, drowsiness, lack of energy or heart attack.

5. What should I know while taking CYSTAGON?

Things you or your child should do

• If you are about to be started on any new medicine, remind your doctor and pharmacist that you are taking CYSTAGON.
• Tell any other doctors, dentists, and pharmacists who treat you that you are taking this medicine.
• Take adequate precautions when using this medicine in children, especially those at risk of the medicine entering their airways or lungs.
• Your medical treatment will include, in addition to CYSTAGON, one or more supplements to replace important electrolytes lost through the kidneys. It is important to take or give these supplements exactly as instructed. If a dose of one of these supplements is missed, do not take extra doses to make up for the missed dose. If several doses of the supplements are missed or weakness or drowsiness develops, call your doctor for instructions.
• Keep all of your doctor's appointments so that your progress can be checked.
• Regular blood tests to measure the amount of cystine present inside white blood cells are necessary to help determine the correct dose of CYSTAGON.
• Regular blood and urine tests are also necessary to measure the levels or various important electrolytes to help your doctor correctly adjust the dose of these supplements.
• Follow your doctor' s advice about tests that are needed to find out if any unwanted serious side effects are occurring. The tests are very important because serious side effects can occur. Ask your doctor to explain the warning signs of the serious side effects.

Things you or your child should not do

• Do not take CYSTAGON to treat any other complaints unless your doctor tells you to.
• Do not give CYSTAGON to anyone else, even if they have the same condition as you.
• Do not stop taking CYSTAGON or change the dose without checking with your doctor.

Driving or using machines

Be careful before you drive or use any machines or tools until you know how CYSTAGON affects you.

This medicine may cause drowsiness or tiredness in some people. If you have any of these symptoms, do not drive, operate machinery or do anything else that could be dangerous.

Children should be careful when riding bicycles or climbing trees.

If you feel light-headed, dizzy or faint when getting out of bed or standing up, get up slowly.

Looking after your medicine

• Keep your capsules in the bottle until it is time to take them.
  If you take your capsules out of the bottle they may not keep well.
• Store below 25°C.

Follow the instructions in the carton on how to take care of your medicine properly.

Store it in a cool dry place away from moisture, heat or sunlight; for example, do not store it:

• in the bathroom or near a sink, or
• in the car or on window sills.

Heat, cold and dampness can destroy some medicines.

Keep it where young children cannot reach it.

A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.

Getting rid of any unwanted medicine

If you no longer need to take this medicine or it is out of date, take it to any pharmacy for safe disposal.

Do not take this medicine after the expiry date.

6. Are there any side effects?

All medicines can have side effects. If you do experience any side effects, most of them are minor and temporary. However, some side effects may need medical attention.

See the information below and, if you need to, ask your doctor or pharmacist if you have any further questions about side effects.

Less serious side effects

Serious side effects

Tell your doctor or pharmacist if you notice anything else that may be making you or your child feel unwell.

Other side effects not listed here may occur in some people.

Reporting side effects

After you have received medical advice for any side effects you experience, you can report side effects to the Therapeutic Goods Administration online at www.tga.gov.au/reporting-problems. By reporting side effects, you can help provide more information on the safety of this medicine.

Always make sure you speak to your doctor or pharmacist before you decide to stop taking any of your medicines.

7. Product details

This medicine is only available with a doctor's prescription.

What CYSTAGON contains

Do not take this medicine if you are allergic to any of these ingredients.

What CYSTAGON looks like

CYSTAGON 50 mg capsules are white, opaque capsules printed with "CYSTA 50" on the body and "MYLAN" on the cap (AUST R 60451).

CYSTAGON 150 mg capsules are white, opaque capsules printed with "CYSTAGON 150" on the body and "MYLAN" on the cap (AUST R 60452).

CYSTAGON 50 mg and 150 mg capsules are available in bottles of 500 capsules.

Who distributes CYSTAGON

Alphapharm Pty Ltd trading as Viatris
Level 1, 30 The Bond
30-34 Hickson Road
Millers Point NSW 2000
www.viatris.com.au
Phone: 1800 274 276

This leaflet was prepared in January 2025.

CYSTAGON^® is a Viatris company trade mark

CYSTAGON_cmi\Jan25/00

Published by MIMS March 2025

1 Name of Medicine

Mercaptamine (cysteamine) bitartrate.

2 Qualitative and Quantitative Composition

Each Cystagon capsule contains either 50 mg or 150 mg of mercaptamine free base as mercaptamine bitartrate.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Cystagon capsules for oral administration, contain mercaptamine bitartrate, a cystine depleting agent which lowers the cystine content of cells in patients with cystinosis, an inherited defect of lysosomal transport.
Cystagon 50 mg are white, opaque capsules printed with CYSTA 50 on the body and MYLAN on the cap.
Cystagon 150 mg are white, opaque capsules printed with CYSTAGON 150 on the body and MYLAN on the cap.

4 Clinical Particulars

4.1 Therapeutic Indications

Cystagon is indicated for the management of nephropathic cystinosis in children and adults.

4.2 Dose and Method of Administration

The initial dose is 0.2 to 0.3 g/m²/day, given in four divided doses, increasing over 4 to 6 weeks to a maintenance dose of 1.3 g/m²/day given in four divided doses for children up to 12 years. The maintenance dose of 1.3 g/m²/day can be calculated from Table 1 which is based on weight and surface area.
Patients over 12 years old and 50 kg bodyweight should receive 2 g/day in four divided doses. This dose should be reached after 4 to 6 weeks as stated above.
If the patient cannot tolerate a specific dose, therapy should be stopped temporarily and restarted at a lower dose.
Intact capsules should not be administered to children under the age of approximately 6 years due to the risk of aspiration. The contents of the capsules may be sprinkled over food for children of this age.

Leukocyte cystine concentration.

4.3 Contraindications

Cystagon is contraindicated in patients who have developed hypersensitivity to it or to mercaptamine or penicillamine.

4.4 Special Warnings and Precautions for Use

If a skin rash develops, Cystagon should be withheld until the rash clears. Cystagon may be restarted at a lower dose under close supervision, then slowly titrated to the therapeutic dose. If a severe skin rash develops such as erythema multiforme bullosa or toxic epidermal necrolysis, Cystagon should not be readministered.
CNS symptoms such as seizures, lethargy, somnolence, depression, and encephalopathy have been associated with mercaptamine. If CNS symptoms develop, the patient should be carefully evaluated, and the dose adjusted as necessary. Neurological complications have been described in some cystinotic patients not on mercaptamine treatment. This may be a manifestation of the primary disorder. Patients should not engage in hazardous activities until the effects of Cystagon on mental performance are known.
Gastrointestinal tract symptoms including nausea, vomiting, anorexia, and abdominal pain have been associated with mercaptamine, sometimes severe. In addition, gastrointestinal ulceration and bleeding have been reported in patients on mercaptamine bitartrate therapy. Physicians should remain alert for signs of ulceration and bleeding and should inform patients and/or parents or guardians about the signs and symptoms of serious GI toxicity and what steps to take if they occur. If these develop, therapy may have to be interrupted and the dose adjusted. A mercaptamine dose of 1.95 g/m²/day (approximately 80 to 90 mg/kg/day) was associated with an increased number of withdrawals from treatment due to intolerance and an increased incidence of adverse events.
Post-marketing reports include one report of interstitial nephritis with early renal failure. A causal relationship between this event and mercaptamine bitartrate therapy has not been established.
There have been post-marketing reports of serious skin lesions in patients treated with high doses of Cystagon or other mercaptamine salts that have responded to mercaptamine dose reduction. These skin lesions are purplish haemorrhagic lesions over the elbow area on both arms and have been described as molluscoid pseudotumors. Skin striae, bone lesions (that have been described as osteopenia, compression fractures, scoliosis and genu valgum) along with leg pain and joint hyperextension may also be present. One patient with serious skin lesions subsequently died of acute cerebral ischemia with marked vasculopathy. Physicians should routinely monitor the skin and bones of patients receiving Cystagon. If similar skin or bone abnormalities appear, the dose of Cystagon should be reduced.
There have been post-marketing reports of benign intracranial hypertension (or pseudotumor cerebri (PTC)) and/or papilloedema associated with Cystagon treatment that has resolved with the addition of diuretic therapy. PTC may be more common in cystinotic patients because of concurrent medication and renal transplantation. Although a causal relationship of PTC to Cystagon has not been established, physicians should monitor patients receiving Cystagon for this condition. Physicians should instruct patients to report any of the following symptoms: headache, tinnitus, dizziness, nausea, diplopia, blurry vision, loss of vision, pain behind the eye or pain with eye movement. A periodic eye examination is needed to identify this condition early and timely treatment should be provided when it occurs to prevent vision loss.
Mercaptamine has occasionally been associated with reversible leukopenia and abnormal liver function studies. Therefore, blood counts and liver function studies should be monitored.

Use in the elderly.

Paediatric use.

Use in neonates.

Effects on laboratory tests.

4.5 Interactions with Other Medicines and Other Forms of Interactions

None had been described.
Cystagon can be administered with electrolyte and mineral replacements necessary for management of the Fanconi syndrome as well as vitamin D and thyroid hormone.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

4.7 Effects on Ability to Drive and Use Machines

The effects of this medicine on a person's ability to drive and use machines were not assessed as part of its registration.

4.8 Adverse Effects (Undesirable Effects)

In three clinical trials, mercaptamine or phosphomercaptamine have been administered to 246 children with cystinosis. Causality or side effects are sometimes difficult to determine because adverse effects may result from the underlying disease.
The most frequent adverse reactions seen involve the gastrointestinal and central nervous systems. These are especially prominent at the initiation of mercaptamine therapy. Temporarily suspending treatment, then gradual reintroduction may be effective in improving tolerance.
Adverse reactions were not collected systemically in the NCCS, but were often listed by investigators. The following rates may therefore be underestimated. The most common events were vomiting, anorexia, fever, diarrhoea, lethargy and rash.
The common (> 1%) and uncommon (0.1 - 1%) adverse events for Cystagon were:

Body as a whole.

Cardiovascular.

Digestive.

Metabolic and nutritional.

Central nervous system.

Skin.

Psychiatric.

Integumentary.

Urogenital.

Clinical laboratory.

General disorders.

Post-marketing surveillance.

Drug abuse and dependence.

Reporting suspected adverse effects.

4.9 Overdose

Overdoses of up to 250 mg/kg have been reported. Symptoms of overdose include vomiting, dehydration, progressive lethargy and cardiac arrest. There is no specific antidote. Respiratory and cardiovascular support may be required.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Normal individuals and persons heterozygous for cystinosis have white cell cystine levels of < 0.2 and usually below 1 nanomol of half-cystine/mg protein, respectively. Individuals with nephropathic cystinosis have elevations of white cell cystine above 2 nanomol of half-cystine/mg protein. White cell cystine is monitored in these patients to determine adequacy of dosing, levels being measured 5 to 6 hours after dosing. In the Long-Term Study (see Section 5.1 Pharmacodynamic Properties, Clinical trials) entry white cell cystine levels were 3.73 nanomol of half-cystine/mg protein (range 0.13 to 19.80 nanomol of half-cystine/mg protein) and were maintained close to 1 nanomol of half-cystine/mg protein with a mercaptamine dose range of 1.3 to 1.95 g/m²/day. After administration of mercaptamine HCl, leukocyte cystine levels fall, with minimum levels at approximately 1 hour.
Because mercaptamine HCl has an unpleasant taste and odour, other formulations have been developed, including phosphocysteamine, the phosphorothioester of mercaptamine that is rapidly converted to mercaptamine in the gut, and mercaptamine bitartrate. Mercaptamine bitartrate has been shown in a transfer study in 8 patients to maintain white cell cystine levels below 1 nanomol of half-cystine/mg protein when substituted for mercaptamine HCl or phosphocysteamine. Total mercaptamine levels 2 and 6 hours post-dosing were higher after mercaptamine bitartrate than for the solutions. Most clinical data have been developed using mercaptamine HCl or phosphocysteamine solutions. In all discussions that follow, administered amounts of various mercaptamine salts will be expressed as amounts of mercaptamine free base.

Mechanism of action.

Clinical trials.

5.2 Pharmacokinetic Properties

Absorption, distribution, metabolism, excretion.

Special considerations.

5.3 Preclinical Safety Data

Genotoxicity.

Carcinogenicity.

6 Pharmaceutical Particulars

6.1 List of Excipients

Cystagon capsules contain the following inactive ingredients: microcrystalline cellulose, pregelatinized maize starch, magnesium stearate, sodium lauryl sulfate, silicon dioxide, croscarmellose sodium, titanium dioxide and gelatin.
The printing inks contain Shellac, ethanol, iron oxide black, butan-1-ol, propylene glycol, isopropyl alcohol, sulfuric acid and strong ammonia solution.

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Store below 25°C. Protect from light and moisture.

6.5 Nature and Contents of Container

Capsules are supplied in a HDPE bottle in a pack size of 500.
Some strengths, pack sizes and/or pack types may not be marketed.

Australian register of therapeutic goods (ARTG).

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking it to your local pharmacy.

6.7 Physicochemical Properties

Chemical structure.

CAS number.

7 Medicine Schedule (Poisons Standard)

S4 (Prescription Only Medicine).

Summary Table of Changes