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Cysteamine (Oral)

Generic name: cysteamine [ sis-TEE-a-meen ]
Brand names: Cystagon, Procysbi
Drug class: Miscellaneous uncategorized agents

Medically reviewed by Last updated on Jul 10, 2023.

Uses for cysteamine

Cysteamine is used to prevent damage that may be caused by the buildup of cystine crystals in organs such as the kidneys (nephropathic cystinosis). Cystinosis is a hereditary disorder that causes an accumulation of the amino acid cystine within cells, forming crystals that can build up and damage the kidneys. This medicine works by removing the extra cystine from the cells of the body.

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

Before using cysteamine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of cysteamine in children 1 year of age and older. However, safety and efficacy have not been established in children younger than 1 year of age.


No information is available on the relationship of age to the effects of cysteamine in geriatric patients.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

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.

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

Proper use of cysteamine

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance of side effects.

This medicine comes with a patient information leaflet. Read and follow the instructions carefully. Ask your doctor or pharmacist if you have any questions.

If you vomit your dose of cysteamine within 20 minutes of taking it, take the dose again. However, if you vomit the dose a second time, do not repeat the dose but wait and take your next dose as scheduled. Also, if vomiting occurs more than 20 minutes after you take your dose, do not repeat the dose.

For children 1 year of age and older, the capsule may be opened and the contents of the capsule sprinkled on food or mixed in formula.

Swallow the delayed-release capsule or granules whole. Do not crush or chew the capsule or contents of the capsule or packet.

Take the delayed-release capsule or granules the same way every day. This means take it at the same time and take it consistently, either with or without food. Avoid high-fat meals close to the time that you will take this medicine.

If you cannot swallow the capsule whole, you may open it and take the capsule or packet contents with certain foods and juices or water:

It is important that you follow any special instructions from your doctor, such as taking dietary supplements, vitamin D, and thyroid hormone. These supplements will replace minerals lost through the kidneys.

If you are taking medicines containing bicarbonate or carbonate, take Procysbi® at least 1 hour before or after these medicines.


The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

You may take a missed dose of Procysbi® as soon as you can up to 8 hours after your scheduled dose. If you missed a dose of Procysbi® and your next dose is less than 4 hours away, wait and take your next dose at the normal time. Do not take 2 doses at one time to make up for a missed dose.


Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Store the delayed-release capsule in its original container. Keep it in a dry place away from direct light.

Precautions while using cysteamine

It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests and eye exams will be needed to check for unwanted effects.

Using high doses of this medicine may cause a condition called Ehler-Danlos-like syndrome. Check with your doctor right away if you have unusual changes on your skin and bones, including bone pain, tenderness, or aching, curved spine, loss of appetite, stretch marks, broken bones, joint problems, or unusual weight loss.

Serious skin reactions (eg, erythema multiforme bullosa, toxic epidermal necrolysis) can occur with this medicine. Check with your doctor right away if you have blistering, peeling, or loosening of the skin, chills, cough, diarrhea, itching, joint or muscle pain, red irritated eyes, red skin lesions, sore throat, sores, ulcers on the skin, or white spots in the mouth or on the lips, or unusual tiredness or weakness while you are using this medicine.

This medicine may cause stomach or bowel ulcers or bleeding. Check with your doctor right away if you have severe stomach pain, nausea, vomiting, loss of appetite, or if you are vomiting blood that looks like coffee grounds.

Check with your doctor right away if you have bloody or persistent diarrhea, loss of bowel control, stomach pain, or vomiting. These may be symptoms of fibrosing colonopathy.

This medicine may affect how your brain is working. Tell your doctor right away if you develop seizures, depression, or if you become very sleepy while taking this medicine.

Check with your doctor right away if you have bulging soft spot on the head of an infant, change in ability to see colors, especially blue or yellow, dizziness, headache, hearing loss, continued ringing in the ears, nausea, blurred or double vision, loss of vision, pain behind the eyes, or pain with eye movement. These may be symptoms of benign intracranial hypertension.

This medicine will lower the number of some types of blood cells in your body. Because of this, you may get infections more easily. To help with these problems, avoid being near people who are sick or have infections. Wash your hands often.

This medicine may cause some people to become dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

Do not drink alcohol while you are using this medicine.

It is important to tell your doctor right away if you are pregnant or have become pregnant while using this medicine.

Side Effects of cysteamine

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

Less common


Incidence not known

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:

Less common

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.

Commonly used brand name(s)

In the U.S.

Available Dosage Forms:

Therapeutic Class: Renal-Urologic Agent

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.