Mercaptamine (cysteamine) (as bitartrate)
Consumer Medicine Information
What is in this leaflet
This leaflet answers some common questions about CYSTAGON. It does not contain all
the available information. It does not take the place of talking to your doctor or
All medicines have risks and benefits. Your doctor has weighed the risks of you taking
CYSTAGON against the benefits they expect it will have for you.
If you have any concerns about taking this medicine, ask your doctor or pharmacist.
Keep this leaflet with the medicine.
You may need to read it again.
What CYSTAGON is used for
CYSTAGON contains a medicine called mercaptamine (cysteamine) that 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 works by reacting with cystine so that the cystine level in cells is
Ask your doctor if you have any questions about why this medicine has been prescribed
Your doctor may have prescribed it for another reason.
CYSTAGON is only available with a doctor's prescription.
Before you take CYSTAGON
When you must not take it
Do not take CYSTAGON if you have an allergy to:
any medicine containing mercaptamine, penicillamine
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
Do not take this medicine after the expiry date printed on the pack or if the packaging
is torn or shows signs of tampering.
If it has expired or is damaged, return it to your pharmacist for disposal.
If you are not sure whether you should start taking this medicine, talk to your doctor.
Before you start to take it
Tell your doctor if you have allergies to any other medicines, foods, preservatives
Tell your doctor if you 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
or blood problems
Tell your doctor if you are pregnant or plan to become pregnant or are breast-feeding.
Your doctor can discuss with you the risks and benefits involved.
If you have not told your doctor about any of the above, tell them before you start
Taking other medicines
Tell your doctor or pharmacist if you are taking any other medicines, including any
that you get without a prescription from your pharmacy, supermarket or health food
Tell your doctor or pharmacist if you are taking an electrolyte replacement supplement.
Replacement of electrolytes (like potassium) is still required during therapy with
Your doctor and pharmacist have more information on medicines to be careful with or
avoid while taking this medicine.
How to 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.
If you do not understand the instructions on the bottle, ask your doctor or pharmacist
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: 1.3g/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 of 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 it
Take your medicine 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 it
Continue taking your medicine for as long as your doctor tells you.
If you forget to take it
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 that you.
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
If you take too much (overdose)
Immediately telephone your doctor or the Poisons Information Centre (telephone 13
11 26) for advice, or go to Accident and Emergency at the nearest hospital, if you
think that you or anyone else may have taken too much CYSTAGON. Do this even if there
are no signs of discomfort or poisoning.
You may need urgent medical attention.
Symptoms of an overdose may include vomiting, dehydration, feeling of tiredness, drowsiness,
lack of energy and a heart attack.
While you are taking CYSTAGON
Things you or your child must 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
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
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 of various
important electrolytes to help your doctor correctly adjust the doses 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
Things you must not do
Do not take CYSTAGON to treat any other complaints unless your doctor tells you to.
Do not give your medicine to anyone else, even if they have the same condition as
Do not stop taking your medicine or change the dosage without checking with your doctor.
Things to be careful of
Be careful driving or operating machinery 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
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
Tell your doctor or pharmacist as soon as possible if you do not feel well while you
are taking CYSTAGON.
This medicine helps most people with nephropathic cystinosis but it may have unwanted
side effects in a few people. All medicines can have side effects. Sometimes they
are serious, most of the time they are not. You may need medical attention if you
get some of the side effects.
Do not be alarmed by the following lists of possible side effects. You may not experience
any of them.
Ask your doctor or pharmacist to answer any questions you may have.
Tell your doctor or pharmacist if you notice any of the following and they worry you:
loss of appetite
unpleasant breath odour
feel tired or fatigued
Tell your doctor as soon as possible if you or your child notices any of the following:
stomach pain, loss of appetite or throwing up blood. Ulcers and bleeding in the digestive
tract have occurred whilst taking this medicine.
skin rash. Your doctor may ask you to temporarily stop taking this medicine until
the rash goes away. If the rash is severe, your doctor may completely stop this medicine.
central nervous system symptoms, such as seizures, depression and excessive sleepiness
low white blood cell count and abnormal liver function tests on blood tests. Your
doctor will monitor you for this.
symptoms such as headache, dizziness, nausea, double vision, blurry vision, loss of
vision, pain behind the eye or pain with eye movement. Patients may get benign intracranial
hypertension, also called pseudotumour cerebri. This is a condition where there is
high pressure in the fluid around the brain.
skin lesions, bone lesions and joint problems. These include skin striae (which are
like stretch marks), bone injuries (such as fractures), bone deformities and joint
Tell your doctor or pharmacist if you notice anything that is making you feel unwell.
Other side effects not listed above may also occur in some people.
After using CYSTAGON
Keep your capsules in the bottle until it is time to take them.
If you take the capsules out of the bottle they may not keep well.
Keep your capsules in a cool dry place away from light where the temperature stays
Do not store CYSTAGON or any other medicine in the bathroom or near a sink. Do not
leave it on a window sill or in the car.
Heat, cold and dampness can destroy some medicines.
Keep it where children cannot reach it.
A locked cupboard at least one-and-a-half metres above the ground is a good place
to store medicines.
If your doctor tells you to stop taking this medicine or the expiry date has passed,
ask your pharmacist what to do with any medicine that is left over.
What Cystagon capsules looks like
Cystagon 50 mg capsules are white, opaque capsules printed with "CYSTA 50" on the
body and "MYLAN" on the cap.
Cystagon 150 mg capsules are white, opaque capsules printed with "CYSTAGON 150" on
the body and "MYLAN" on the cap.
CYSTAGON 50 mg and 150 mg capsules are available in bottles of 500 capsules.
Each capsule contains mercaptamine free base as mercaptamine bitartrate.
The capsules contain the following inactive ingredients:
pregelatinised maize starch
sodium lauryl sulfate
The printing ink on the capsules contains the following inactive ingredients:
iron oxide black
strong ammonia solution.
Alphapharm Pty Ltd trading as Viatris
Level 1, 30 The Bond
30 - 34 Hickson Road
Millers Point NSW 2000
Phone: 1800 274 276
Australian Registration Numbers:
50 mg Capsules: AUST R 60451
150 mg Capsules: AUST R 60452
CYSTAGON® is a Viatris company trademark.
This leaflet was revised in October 2023.