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Overview: Cysteamine is used to treat a rare inherited disorder called nephropathic cystinosis. People with this disorder have high levels of cystine, which forms crystals in the kidneys and other organs. Cysteamine works by changing cystine to another substance that can be cleared from the body. This helps prevent crystals from forming. Common side effects include nausea or vomiting, stomach pain, change in the smell of your breath or skin, diarrhea, and tiredness. Serious side effects are rare but include changes to the skin, joints, bones, or gut.

Uses

What is cysteamine used for?

Cysteamine is used to treat a rare, inherited disorder called nephropathic cystinosis, which affects the kidneys and other organs. 

Cysteamine may also be used for other conditions as determined by your health care provider.

See also: Cysteamine ophthalmic

How does cysteamine work (mechanism of action)?

People with a rare, inherited condition called nephropathic cystinosis have too much cystine (an amino acid) in their bodies. When cystine levels get too high, it forms crystals in the kidneys and other organs, causing serious health effects. Cysteamine works by changing cystine to another substance that can be cleared from the body. This helps prevent crystals from forming and protects organ function.

How is cysteamine supplied (dosage forms)?

Brands and other names

  • Cystagon
  • Procysbi

Dosage forms and strengths

  • 25 mg and 75 mg delayed-release oral capsules
  • 75 mg and 300 mg packets of delayed-release oral granules
  • 50 mg and 150 mg oral capsules

How should I store cysteamine?

Oral Capsule. Cysteamine capsules should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). They can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting them. Store in a cool, dry place and protect from light and moisture.

Delayed-Release Oral Capsule. Cysteamine delayed-release oral capsules should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). Store in a cool, dry place and keep in the original container. Do not remove the moisture-absorbing packet (desiccant) from the bottle. Protect from light and moisture. Throw away the medicine by the date written on the package.

Delayed-Release Oral Granule. Cysteamine delayed-release oral granules should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). Store in a cool, dry place and keep in the original container. Protect from light and moisture. Do not open the packet until you are ready to use it. Throw away the medicine by the date written on the package.

Side Effects

What are the most common side effects of cysteamine?

The most common side effects of cysteamine are listed below. These side effects may vary depending on your age and which form of cysteamine you are taking. Tell your health care provider if you have any of these side effects that bother you.

  • Nausea or vomiting
  • Stomach pain
  • Change in the smell of your breath or skin
  • Fever
  • Loss of appetite
  • Diarrhea
  • Tiredness
  • Rash (see below)
  • Headache
  • Pink eye
  • Stomach flu
  • Changes in salt or electrolyte levels

There may be other side effects of cysteamine that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of cysteamine?

While less common, the most serious side effects of cysteamine are described below, along with what to do if they happen.

Severe Allergic Reactions. Cysteamine may cause allergic reactions, which can be serious. Stop taking cysteamine and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Rash or Severe Skin Reactions. Cysteamine may commonly cause a skin rash, but it can also cause skin reactions that can be severe. These reactions include erythema multiforme and toxic epidermal necrolysis (TEN), which can lead to death if not treated. If you develop a rash, stop cysteamine and call your health care provider right away. Get emergency help if you have any of the following symptoms.

  • Painful red or purple skin that looks burned and peels off
  • Flat red rash or blisters on your skin, mouth, nose, and genitals
  • Red, painful, watery eyes
  • Flu-like symptoms including fever, chills, and muscle aches

Skin, Bone, or Joint Problems. Cysteamine has been reported to cause changes to the skin, bones, or joints. In some cases, these changes can be serious. Call your doctor right away if you notice any of the following changes.

  • Stretch marks or other changes to the skin, such as spots or damage
  • Broken or deformed bones
  • Leg pain
  • Joint pain 
  • Joints moving out of their normal range (hyperextension)

Stomach or Intestine Problems. Cysteamine can increase the risk of bleeding and ulcers in your gut, especially if you have a history of stomach ulcers or bleeding. Taking cysteamine delayed-release capsules or granules for a long time can increase your risk of a condition called fibrosing colonopathy, where scar tissue builds up in the colon and causes strictures or blockages. Call your health care provider right away if you have any of the following symptoms of these conditions.

  • Nausea or vomiting, including vomiting blood
  • Black or tarry poop
  • Severe or bloody diarrhea
  • Severe constipation
  • Stomach pain that does not go away
  • Loss of appetite
  • Feel faint

Seizures. Some people who have taken cysteamine have reported having seizures. There are many different types of seizures and some of them are not easy to recognize. Stop taking cysteamine and call your health care provider if you have any of the following signs that a seizure is happening or could happen.

  • Muscle twitching, jerking, spasms, tremors, or other uncontrolled movements
  • Stiffening of your arms and legs
  • Feeling anxious, nervous, confused, or a sense of dread
  • Feeling dizzy or lightheaded
  • Falling or losing consciousness

Brain or Central Nervous System (CNS) Effects. Cysteamine can affect your brain or central nervous system (CNS). Call your health care provider right away if you have the following symptoms.

  • Feeling unusually weak or tired
  • Depression
  • Sleepiness
  • Confusion or slowed thinking

Increased Pressure Around the Brain. Cysteamine can increase the pressure around the brain, a serious condition called pseudotumor cerebri (or increased intracranial pressure). Keep all appointments with your health care provider, including for eye exams. Stop taking cysteamine and call your health care provider right away if you have any of the following symptoms.

  • Dizziness
  • Ringing in the ears
  • Nausea and vomiting
  • Severe headache
  • Vision changes

Changes in Certain Blood Levels. Cysteamine may cause low levels of white blood cells (leukopenia) or high levels of an enzyme called alkaline phosphatase (ALP) in some people. These changes may not cause any symptoms. It is important to keep all appointments for blood work so that your health care provider can monitor your blood levels. 

Warnings & Precautions

Who should not use cysteamine?

Allergies to Ingredients. People who are allergic to any of the following should not take cysteamine.

  • Cystagon
  • Cysteamine
  • Penicillamine
  • Procysbi
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific cysteamine products they stock.

What should I know about cysteamine before using it?

Do not take cysteamine unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share cysteamine with other people, even if they have the same condition as you. It may harm them.

Keep cysteamine out of the reach of children.

Cysteamine can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how cysteamine affects you.

There are several forms of cysteamine available and they may need to be taken in different ways. Follow the instructions that come with your medicine and ask your pharmacist or other health care provider if you are not sure how to take the cysteamine form you are prescribed.

Swallow cysteamine oral capsules whole with a full glass of liquid. Do not crush or chew the capsules. If you are unable to swallow the capsules whole, you can open them and mix the contents with food. 

Cysteamine delayed-release capsules should be swallowed whole with water or any fruit juice other than grapefruit juice. Do not crush or chew the capsules. If you are unable to swallow the capsules whole, you can open the capsules and mix the contents with food or juice. Ask your pharmacist about the best way to take the delayed-release capsules if you have trouble swallowing them.

Before taking cysteamine delayed-release granules, they should be mixed with no more than four ounces (1/2 cup) of applesauce, berry jelly, or fruit juice (other than grapefruit juice). It is important to swallow the granules whole, without chewing or crushing. Take the dose within 30 minutes of mixing. 

Keep all follow up-appointments. Your health care provider may need to monitor your blood work to help prevent side effects and determine the best dose of cysteamine for you.

What should I tell my health care provider before using cysteamine?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if cysteamine is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Skin problems
  • Bone problems
  • Blood disorders, such as low white blood cell levels
  • Liver problems
  • Stomach problems, including ulcers or bleeding
  • Seizures
  • Severe tiredness, lack of energy, depression, or are unable to think clearly
  • Drink alcohol

Other Medicines and Supplements. Cysteamine may interact with other medicines and supplements. Before using cysteamine, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how cysteamine could affect pregnancy or harm an unborn baby. Tell your health care provider right away if you are or plan to become pregnant. Your health care provider will advise you if you should take cysteamine while you are pregnant or trying to get pregnant.

Breastfeeding. It is not known if cysteamine passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will advise you if you should stop breastfeeding or stop cysteamine.

Interactions

Does cysteamine interact with foods or drinks?

Oral Capsule. There are no known interactions between cysteamine oral capsules and foods or drinks. It is unknown if drinking alcohol will affect cysteamine oral capsules.

Delayed-Release Oral Capsule or Granule. Avoid taking cysteamine delayed-release capsules or granules within two hours before food or within 30 minutes after food. If you are unable to avoid food during this time, you may eat a small amount of low-fat food (no more than 4 ounces or 1/2 cup) within one hour before or after taking cysteamine. It is important to always take cysteamine the same way, either without any food at all or with a small amount of food. You should not take cysteamine delayed-release oral capsules with grapefruit juice or mix the oral granules in grapefruit juice. Ask your pharmacist or other health care provider if you have questions about how to take your medicine.

Do not drink alcohol while you are taking cysteamine delayed-release capsules or granules. Alcohol can change the way that these products work. This may increase the risk of serious side effects and make the medicine not work as well.

Does cysteamine interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using sodium bicarbonate, which is a medicine used for heartburn and stomach ulcers and is in some over-the-counter (OTC) and prescription medicines, such as Alka-Seltzer, Zegerid, and Zegerid OTC.

This may not be a complete list of medicines that can interact with cysteamine. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much cysteamine?

If you or someone else has used too much cysteamine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of cysteamine?

Oral Capsule. If you miss a dose, take it as soon as you remember. If the next scheduled dose is due in less than two hours, skip the missed dose and only take the next dose. Do not take double or extra doses.

Oral Delayed-Release Oral Capsule or Granule. If you miss a dose, take it as soon as you remember. If the next scheduled dose is due in less than four hours, skip the missed dose and only take the next dose. Do not take double or extra doses. It is important not to miss doses of this medicine.