Key takeaways
- Cystagon (cysteamine bitartrate) is a prescription drug used to treat nephropathic cystinosis in children and adults. This is a rare genetic condition that causes a buildup of cystine (an amino acid) in the body.
- Common side effects of Cystagon include mild issues like fever and nausea. Serious side effects, though rare, can include vision issues and skin rashes. Children may experience additional side effects at higher doses.
- Cystagon comes as an oral capsule that’s typically taken four times each day. The dose varies depending on age and body weight, with doctors typically starting people at a lower dose and gradually increasing it to the maintenance dose to minimize side effects.
To learn about Cystagon’s uses, see the “Uses for Cystagon” section.
Cystagon basics
Cystagon contains the active ingredient cysteamine. It belongs to a group of drugs called cysteine-depleting agents.
Cystagon is a brand-name medication. A generic version of the drug isn’t currently available.
Cystagon is used to treat nephropathic cystinosis in adults and children of any age.
Nephropathic cystinosis is a rare genetic condition that causes the build up of an amino acid called cystine. It may cause symptoms such as below average growth and dehydration in infants and vision problems in older children and adults.
Cystagon’s mechanism of action (how it works) to treat nephropathic cystinosis is by helping the body get rid of cystine. It converts this amino acid into a form the body can eliminate more easily. This reduces cystine buildup in your cells and in organs such as your kidneys.
Like most drugs, Cystagon may cause mild to serious side effects. The following lists contain some of the more common side effects Cystagon may cause, but they don’t include all possible side effects.
Keep in mind that side effects of a drug can depend on your age, other health conditions you have, and other medications you take.
Your doctor or pharmacist can tell you more about the potential side effects of Cystagon. They can also suggest ways to help reduce or manage them.
Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medications safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while taking Cystagon and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.
Mild side effects
Here’s a list of some of the mild side effects Cystagon can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read the drug’s prescribing information.
Mild side effects of Cystagon that have been reported include:
- appetite loss
- dehydration
- diarrhea
- fatigue
- fever
- headache
- indigestion (upset stomach)
- mild skin rash
- nausea
- vomiting
Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.
Serious side effects
Serious side effects from Cystagon can occur, but they aren’t common. If you have serious side effects from Cystagon, call your doctor right away. If you think you’re having a medical emergency, you should call 911 or your local emergency number.
Serious side effects of Cystagon that have been reported include:
- abnormal liver function test results
- central nervous system (CNS) side effects, including:
- digestive tract ulcers or bleeding
- intracranial hypertension (increased pressure in the brain)
- kidney side effects, including interstitial nephritis
- leukopenia (low white blood cell count)
- severe skin rash, such as toxic epidermal necrolysis
Side effects in children
Cystagon is used to treat nephropathic cystinosis in children of any age. Side effects in children are similar to those in adults.
Children who receive a high dose of Cystagon may be at risk for additional side effects, such as:
- bone fractures and other bone injuries
- joint problems, such as hyperextension
- skin lesions (such as stretch marks)
Let your child’s doctor know right away if your child develops side effects during treatment, or if you have questions about side effect symptoms your child might develop.
Allergic reactionFor some people, Cystagon can cause an allergic reaction.
In general, symptoms of an allergic reaction can be mild or serious.
What might helpIf you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should continue Cystagon treatment.
If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.
If your doctor confirms you’ve had a serious allergic reaction to Cystagon, they may have you switch to a different treatment.
The Cystagon dosage your doctor prescribes will depend on several factors. These include:
- your age
- your body weight
- whether you experience intolerable side effects during treatment
The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. They’ll determine the best dosage to fit your needs.
Form and strengths
Cystagon comes as an oral capsule in two strengths: 50 milligrams (mg) and 150 mg.
Recommended dosages for nephropathic cystinosis
The recommended maintenance dosage of Cystagon for adults is 500 mg four times each day, for a total daily dose of 2,000 mg.
To begin treatment, doctors typically prescribe a lower dose than the maintenance dose. This is usually 1/4 to 1/6 of the 2,000-mg daily maintenance dosage. Then they’ll gradually increase your dose over 4 to 6 weeks up to the maintenance dose. Slowly increasing your dose over time helps your body get used to Cystagon and lowers your risk of side effects.
The maximum recommended dosage of Cystagon is 1.95 grams per square meter (m2) of body surface area (BSA) per day, divided into four doses. (BSA is calculated based on your height and body weight.) Your doctor will calculate your maximum recommended Cystagon dosage.
Children’s dosage
For children ages 12 years and older, Cystagon’s dosage for nephropathic cystinosis is the same as for adults.
For children less than 12 years old, the recommended maintenance dosage depends on the child’s body weight in pounds (lb) as described in the following table.
| Child’s weight | Cystagon dosage: every 6 hours, four times daily |
|---|---|
| 0 to 10 lb | 100 mg |
| 11 to 20 lb | 150 mg |
| 21 to 30 lb | 200 mg |
| 31 to 40 lb | 250 mg |
| 41 to 50 lb | 300 mg |
| 51 to 70 lb | 350 mg |
| 71 to 90 lb | 400 mg |
| 91 to 110 lb | 450 mg |
| over 110 lb | 500 mg |
Doctors typically start a child’s treatment with a lower dose than the maintenance dose shown in this chart. The starting dose is usually 1/4 to 1/6 of the maintenance dose. Prescribing a lower starting dose allows your child’s body time to adjust to the drug, reducing the risk of side effects.
If your child tolerates the starting dose, their doctor will adjust the dose over about 4 to 6 weeks until your child is taking the recommended maintenance dosage based on their weight.
The maximum recommended Cystagon dosage in children is 1.95 grams per square meter (m2) of body surface area (BSA) per day, divided into four doses. (BSA is calculated based on your child’s height and weight.) Your child’s doctor will calculate your child’s maximum recommended Cystagon dosage.
How to take
Your doctor will explain how you should take Cystagon, including how much to take and how often. Be sure to follow their instructions.
About taking Cystagon
The following are some common questions about taking Cystagon.
- Can Cystagon be chewed, crushed, or split? You should not chew or crush Cystagon capsules. If you have trouble swallowing pills, you can open the Cystagon capsule and sprinkle the pellets onto a small amount of applesauce or other food. Consume the mixture right away.
- Should I take Cystagon with food? Cystagon can be taken with or without food.
- Is there a best time of day to take Cystagon? You’ll take Cystagon four times per day, according to your doctor’s instructions. You should try to take your doses on a consistent schedule. This helps keep a steady level of the drug in your body, which helps it work effectively.
- What if I miss a dose of Cystagon? If you miss a dose of Cystagon, try to take it as soon as possible. But if your next dose is due within 2 hours, skip the missed dose and take the next dose at its usual time. Do not take two doses at once to make up for a missed dose, as this could increase your risk of side effects.
- Will I need to take Cystagon long term? Cystagon is typically a long-term treatment. If you and your doctor determine that it’s safe and effective for your condition, you’ll likely take it long term.
- How long does Cystagon take to work? Cystagon works to lower leukocyte cystine levels as soon as you take a dose. Minimal leukocyte cystine levels occur about 1 to 2 hours after taking a dose and will rise steadily unless Cystagon is taken four times each day as directed.
Overdose
Do not take more Cystagon than your doctor prescribes, as this can lead to harmful effects. Symptoms caused by an overdose can include dehydration and vomiting.
What to do in case of overdose
Call your doctor if you think you’ve taken too much Cystagon. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.
Cystagon isn’t known to interact with other medications, herbs, supplements, foods, or alcohol. The manufacturer didn’t list any interactions in the drug’s prescribing information. But this doesn’t mean interactions won’t be recognized in the future. For example, new drugs could be approved that interact with Cystagon.
Before starting treatment with this medication, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also, tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.
If you have questions about interactions that may affect you, talk with your doctor or pharmacist.
Whether you have health insurance or not, cost may be a factor when you’re considering Cystagon. What you’ll pay for this medication may depend on several factors, such as your treatment plan, your insurance coverage, your location, and the pharmacy you use.
Here are a few things to consider regarding cost:
- Comparing pharmacies: The price of Cystagon may vary depending on which pharmacy you use, so it can help to compare prices across pharmacies to find the lowest cost.
- Savings program: A program called Viatris Patient Assistance Program is available for Cystagon. For more information and to find out whether you’re eligible for support, call 888-417-5780 or visit the program website.
If you have questions about how to pay for your prescription, talk with your doctor or pharmacist.
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The following is important information to consider and discuss with your doctor or pharmacist before taking Cystagon.
Pregnancy and Cystagon
Based on animal studies, there may be risks to taking Cystagon during pregnancy. But there are also risks with having unmanaged nephrotic cystinosis.
If you’re planning a pregnancy or can become pregnant, talk with your doctor about potential treatments for nephrotic cystinosis during pregnancy. Together, you can consider the risks and benefits of your treatment options and decide whether or not you should take Cystagon while you’re pregnant.
Birth control and Cystagon
It’s not known whether Cystagon is safe to take during pregnancy. Therefore, if you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control options while you’re taking Cystagon.
Cystagon and breastfeeding
There haven’t been enough studies to show whether cysteamine passes into human breast milk. However, because animal studies show potential concerns, it’s recommended that you talk with your doctor about your options if you’re currently breastfeeding or planning to do so.
Before starting Cystagon, discuss your health history with your doctor. Cystagon may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to tell your doctor if any of the following apply to you:
- bone problem, such as a recent bone fracture
- blood cell condition, such as leukopenia
- nervous system condition, including excessive sleepiness, depression, and seizures
- liver disease
- previous allergic reaction to this or a similar drug
- pregnancy
- breastfeeding
Note: For more information about the potential negative effects of Cystagon, see the “Side effects of Cystagon” section.
Procysbi (extended-release cysteamine) is a drug similar to Cystagon that’s used to treat nephropathic cystinosis.
If you’d like to explore this alternative to Cystagon, talk with your doctor. They can help determine the treatment option that’s best for your condition.
Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.