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Cystagon

cysteamine
Used for Lysosomal Storage Disease
Used for Lysosomal Storage Disease

Cystagon (cysteamine) is a cystine depleting agent. It's used in adults and children to treat a rare genetic condition called nephropathic cystinosis, which is a build-up of cystine (a protein) in the kidneys. This medication is available as immediate-release capsules that are taken whole by mouth every 6 hours. But if you're having trouble swallowing, or if Cystagon (cysteamine) is prescribed for a child under 6 years old, the contents of capsules can be sprinkled on food and consumed. Common side effects include vomiting, low appetite, and weakness.

Reviewed by:
reviewer
Robert Chad Hakim, PharmD, BCCCP
reviewer
Kristianne Hannemann, PharmD
Last reviewed on February 2, 2024
BasicsSide effectsPros & consPharmacist tipsFAQsWarningsDosageInteractionsContraindicationsAlternativesReferencesPricesMedicare
basics-icon

What is Cystagon (cysteamine)?

What is Cystagon (cysteamine) used for?

How Cystagon (cysteamine) works

Cystinosis is a genetic condition where there's a build-up of cystine (a protein) in the body. This happens because lysosomes, which are parts of the cell that are responsible for breaking down cystine, aren't working properly.

Cystagon (cysteamine) is a cystine depleting agent. It works by attaching to lysosomes to help them work better at removing cystine from your body.

Are you looking for information on Procysbi (cysteamine bitartrate) extended-release or Cystaran (cysteamine) eye drops instead?

Drug Facts

Common BrandsCystagon
Drug ClassCystine-depleting agent
Controlled Substance ClassificationNot a controlled medication
Generic StatusNo lower-cost generic available
AvailabilityPrescription only
basics-icon

What are the side effects of Cystagon (cysteamine)?

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

  • Vomiting (35%)
  • Low appetite (31%)
  • Fever (22%)
  • Diarrhea (16%)
  • Weakness (11%)
  • Rash (7%)

Other Side Effects

  • Dehydration
  • Bad breath
  • Nausea
  • Stomach pain
  • Constipation
  • Headache
  • Sleepiness
  • Changes in mood

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following.
  • Severe skin reactions: fever, hives, rash, skin reddening, blisters, peeling skin, swelling of the lips or tongue, difficulty breathing
  • Stomach bleeding: vomiting blood, bloody or dark stools, severe stomach pain or discomfort
  • Brain and mental health side effects: depression, seizures, severe dizziness and sleepiness, confusion
  • High blood pressure in the brain: headache, ringing in the ears, dizziness, nausea, double or blurry vision, vision loss, pain behind eye(s) or with eye movement

Source: DailyMed

The following side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Blurred vision

decrease or change in vision

eye pain, redness, itching, irritation, or swelling

headache

sensitivity of the eyes to light

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Watering of the eyes

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

pros-and-cons

Pros and cons of Cystagon (cysteamine)

thumbs-up

Pros

Lowers cystine levels by about 50% after a dose

Works well to protects your kidneys from cystine build-up

Capsules can be opened and sprinkled onto food for people who have trouble swallowing pills

Can be used in children of all ages

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Cons

Needs to be taken 4 times per day

Requires routine lab tests

Can't be taken during pregnancy

Can't be taken by people who have an allergy to penicillamine (Depen)

pharmacist-tips

Pharmacist tips for Cystagon (cysteamine)

pharmacist

  • Mark your appointments in your calendar to see your provider to be examined and get any blood tests done. This will help make sure you're being properly monitored to see how well Cystagon (cysteamine) is working and how safe it is for you.

    • Your provider will order blood tests that measure your cystine levels about every 3 months during treatment to see how well Cystagon (cysteamine) is working for you. They'll also monitor your liver function tests and blood cell counts to make sure they're within normal range.

      • If you're having trouble swallowing the capsules, sprinkle the contents of the capsule over food and take the dose. Also do this for a child under 6 years old who's prescribed Cystagon (cysteamine) because they're at high risk for choking on the capsule.

        • Take Cystagon (cysteamine) four times per day at about the same times every day. You can take Cystagon (cysteamine) with or without food. But nausea is a common side effect, so taking it with food might help.

          • If you miss a dose of Cystagon (cysteamine), take it as soon as you remember. But if it's within 2 hours of your next dose, skip the missed dose and take your next dose as you would regularly. Don't double up the dose to make up for the missed dose.

            • Cystagon (cysteamine) can make you sleepy and dizzy, which can affect your ability to focus. It can also cause weakness and confusion. Don't drive or do anything that requires concentration until you know how this medication makes you feel.

              • Avoid drinking alcohol because it can worsen side effects from Cystagon (cysteamine), such as upset stomach, sleepiness, depression, and dizziness. It can also affect how well the medication works in your body.

                • Tell your provider if you notice a skin rash while taking Cystagon (cysteamine). They'll make sure the rash isn't a sign of a more severe skin problem. You'll likely need to stop the medication until the rash clears.

                  • Cystagon (cysteamine) raises the risk of stomach bleeding, so tell your provider right away if you experience unexplained vomiting, stomach pain, dark-colored stools, or blood in your vomit or stool.

                    faqs

                    Frequently asked questions about Cystagon (cysteamine)

                    What is nephropathic cystinosis?
                    Cystinosis is a rare genetic condition where your body can't remove cystine (a protein) properly from cells. This causes cystine to build up and form crystals in many organs. When cystine builds up in the kidneys (nephropathic cystinosis), it can cause kidney failure. Without treatment, this condition is life-threatening. Cystagon (cysteamine) treats nephropathic cystinosis by clearing the build up of cystine.
                    What's the difference between Cystagon and Procysbi?
                    Both medications contain the same active ingredient, cysteamine bitartrate. The main difference between them is how the medication is released in the body. Cystagon is an immediate-release capsule, which means the medication is released into your body quickly after you take the dose. Procysbi comes as delayed-release capsules and delayed-release granules, which means the medication is released slowly after you take the dose. Cystagon capsules are typically taken 4 times per day, whereas Procysbi capsules are taken 2 times per day. A small study showed both medications work well to lower cystine levels, but Procysbi might have a lower risk of side effects.
                    Does Cystagon (cysteamine) cure cystinosis?
                    No, Cystagon (cysteamine) won't cure cystinosis. But it can protect your kidneys from any further damage by lowering the cystine levels in your body. If you stop taking the medication, cystine can build up in your organs and cause problems. Your provider will likely have you continue taking Cystagon (cysteamine) as long as it's helping keep your cystine levels low and you're not having any serious side effects.
                    Does Cystagon (cysteamine) cause weight gain?
                    No, weight gain wasn't reported by people taking Cystagon (cysteamine) during clinical trials. But some people did experience loss of appetite and weight loss. Talk to your provider if you notice changes in your body weight after starting treatment. Your provider might need to adjust your dose of Cystagon (cysteamine) based on your body weight.
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                    What are the risks and warnings for Cystagon (cysteamine)?

                    Cystagon (cysteamine) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

                    risk-warning

                    Severe skin reactions

                    People have reported skin rashes after starting Cystagon (cysteamine). Sometimes, these rashes are temporary and go away after the medication is stopped. But rarely, this medication can cause life-threatening skin reactions, such as toxic epidermal necrolysis (TEN). Let your provider know right away if you notice changes in your skin such as rash, blisters, skin reddening, or skin peeling. Depending on how serious your reaction is, your provider might ask you to temporarily stop Cystagon (cysteamine) and restart you at a lower dose, or stop this medication completely.

                    Some people have also reported purplish skin lesions after taking higher doses of Cystagon (cysteamine). Sometimes, they've also experienced other skin changes, bone pain, and higher risk of fracture along with these lesions. Your provider will examine your skin and bones regularly when you're taking Cystagon (cysteamine). If needed, they'll lower your dose of the medication.

                    risk-warning

                    Stomach bleeding and ulcers

                    • Risk factors: Older age | History of stomach bleeding or ulcers | Bleeding problems | Liver problems | Taking other medications that raise your risk of bleeds | Drinking alcohol | Smoking

                      Cystagon (cysteamine) can raise your risk for serious stomach problems, including bleeding and ulcers (sores). Stomach bleeding is a dangerous condition that requires treatment right away. Your risk for stomach bleeds is even higher if you're taking Cystagon (cysteamine) with other medications that can put you at risk, such as blood thinners (anticoagulants). Seek medical help right away if you're feeling faint, vomiting blood, have bloody or dark stools, or have severe stomach pain or discomfort that doesn't go away while you're taking Cystagon (cysteamine).

                      risk-warning

                      Brain and mental health side effects

                      Cystagon (cysteamine) can affect your brain, which can cause symptoms, such as sleepiness, depression, fatigue, seizures, and brain swelling. Don't drive or do anything that requires you to focus until you know how this medication affects you. Let your provider know if you experience any of these symptoms because they might prescribe a lower dose of Cystagon (cysteamine).

                      risk-warning

                      High blood pressure in the brain (intracranial hypertension)

                      Although very rare, there have been a few reports of Cystagon (cysteamine) causing high blood pressure in the blood vessels in the brain, or intracranial hypertension. This can lead to changes in vision and cause symptoms like headache, nausea, vomiting, dizziness, and ringing in the ears. Your provider will likely perform eye examinations before and regularly throughout treatment with Cystagon (cysteamine), including looking at your eyes for papilledema (or eye swelling).

                      dosage

                      Cystagon (cysteamine) dosage forms

                      Typical dosing for Cystagon (cysteamine)

                      Your provider will typically prescribe a lower dose of Cystagon (cysteamine) to start, then raise it slowly over 4 to 6 weeks until you've reached the recommended maintenance dose.

                      • People ages 12 years and older (weighing 110 lbs or more): The typical maintenance dose is 500 mg by mouth every 6 hours.

                      • People under 12 years old (weighing 110 lbs or less): Your child's provider will calculate their dose based on body surface area (BSA), which takes into account your child's height and weight. In general, the maintenance dose ranges from 100 mg to 450 mg by mouth every 6 hours.

                      Your provider will adjust your dose based on how well the medication is lowering your cystine levels and if you're having side effects.

                      interactions

                      Interactions between Cystagon (cysteamine) and other drugs

                      Cystagon (cysteamine) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Cystagon (cysteamine). Please note that only the generic name of each medication is listed below.

                      Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

                      contraindications-icon

                      Cystagon (cysteamine) contraindications

                      Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Cystagon (cysteamine) will not be safe for you to take.
                      alternatives

                      What are alternatives to Cystagon (cysteamine)?

                      There are a number of medications that your doctor can prescribe in place of Cystagon (cysteamine). Compare a few possible alternatives below.
                      Cystagon (cysteamine)
                      Used for:
                      View Prices
                      Procysbi (cysteamine)
                      Used for:
                      View Prices

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                      References

                      Best studies we found

                      Chen, J. J. (2024). Papilledema. Merck Manual Consumer Version.

                      Cystinosis Research Network. (n.d.). About cystinosis.

                      Mylan Pharmaceuticals Inc. (2021). Cystagon- cysteamine bitartrate capsule [package insert]. DailyMed.

                      View All References (6)

                      National Eye Institute. (2023). Idiopathic intracranial hypertension.

                      National Human Genome Research Institute. (2024). Lysosome.

                      National Kidney Foundation. (n.d.). Kidney failure.

                      National Kidney Foundation. (n.d.). Nephropathic cystinosis: Evaluation and management.

                      National Kidney Foundation. (n.d.). Nephropathic cystinosis.

                      van Stein, C., et al. (2021). A comparison of immediate release and delayed release cysteamine in 17 patients with nephropathic cystinosis. Orphanet Journal of Rare Diseases.

                      GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.
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