Cysteamine (oral route)

When prescribed as an orally administered medicine, cysteamine treats patients suffering from nephropathic cystinosis by reducing the amount of the amino acid cystine in the kidneys.


Cysteamine is commonly marketed under the brand names Cystagon or Procysbi and is used in the treatment of a rare genetic disorder called nephropathic cystinosis. This disease causes the build-up of an amino acid called cystine in the kidneys, as well as other organs. This debilitating condition can cause kidney failure and other serious medical problems if it goes untreated. Cysteamine is available as either a capsule or a delayed release capsule, both of which are prescribed based on the nature of the patient's condition.

Cysteamine is often used as a treatment in combination with other drugs, vitamins and mineral supplements to combat many of the symptoms caused by nephropathic cystinosis. While under this course of treatment, a patient may need to have regular blood tests, skin examinations and bone examinations in order to determine if the dosage is sufficient to reduce the cystine levels and prevent the debilitating effects of the disorder. For both adults and children who suffer from nephropathic cystinosis, this drug can be a very beneficial treatment option.

Conditions treated

  • Nephropathic cystinosis

Type of medicine

  • Stable aminothiol

Side effects

Cysteamine may cause some unwanted side effects along with its intended effects. Not all of these side effects will necessarily occur in every patient, but there is a chance that they will in certain cases. If any of the following serious side effects occur they might require additional medical attention.

Some of the more common serious side effects of cysteamine include gastrointestinal effects, such as abdominal pain, diarrhea, nausea, vomiting and loss of appetite. Patients commonly experience drowsiness, fevers and skin rashes, as well. Less common serious side effects include neurological effects, such as confusion, dizziness, headaches and trembling. Some patients uncommonly experience sore throats while taking the medicine and there have been occasional bouts of depression reported. More rarely experienced, but just as serious, side effects include convulsions, an increase in thirst and unusual fatigue.

Additionally, some serious side effects have been recorded while patients have been using cysteamine, although their incidence is not known. These serious side effects include the following:

  • Blistering, peeling, or loosening of the skin
  • Blurred or double vision
  • Bone lesions
  • Bulging soft spot on head of an infant
  • Change in the ability to see colors, especially blue or yellow
  • Chills
  • Continuing ringing or buzzing or other unexplained noise in the ears
  • Cough
  • Eye pain
  • Hearing loss
  • Itching
  • Joint or muscle pain
  • Loss of appetite
  • Loss of vision
  • Pain behind the eyes
  • Pain in the legs
  • Pain with eye movement
  • Red skin lesions, often with a purple center
  • Red, irritated eyes
  • Reddish purple lines on the arms, face, legs, trunk, or groin
  • Severe headache
  • Sore throat
  • Sores, ulcers, or white spots in the mouth or on the lips

Not all side effects will necessarily be serious enough to merit medical attention. Some are considered routine effects that the body goes through while adjusting to the cysteamine in the system. However, if the symptoms are more intense than expected or last for a longer duration, they may be indicative of a more serious medical problem and a doctor should be consulted. Routine temporary side effects include bad breath, constipation, hives, welts, redness of the skin, unusual fatigue, weakness and sudden weight loss.


Cysteamine is a prescription drug that should only be used as directed by a physician. All doctor's orders and directions on the label should be followed. If the following information differs from these, your prescription should be followed, as the information here only represents average doses as indicated by the manufacturer.

The strength of the dose and the number of doses taken each day may vary based upon the health of the individual who is prescribed it and the level of advancement of symptoms.

To prevent the buildup of cystine crystals in the kidneys, the starting dose for adults taking oral capsules of cysteamine is usually determined by the doctor and is based on the health of the patient at the time. This dose may be gradually increased to compensate for increased levels of cystine.

A pediatric specialist will need to determine the starting dose for children and this will be based on body size and weight of the child.

In the case of the use of delayed-release capsules by adults or children, the guidelines are the same, but the capsules will generally be taken every 12 hours. When patients are switching from delayed release to immediate release capsules, the dose will usually be equivalent to the dose that was previously being taken.

If for any reason a dose is missed, it should be taken as soon as possible, but skip to the next scheduled dose if the next dose is too close. Do not take a double dose of cysteamine, as this can cause an unsafe condition or overdose. In general, it is safe to take a dose of cysteamine up to eight hours after a dose is missed, but it should not be taken if there are less than four hours until the next dose is scheduled.

Take cysteamine only as directed by your doctor, for the condition for which it was prescribed. Be careful not take more of it or to take it more frequently than directed. Taking it for a longer period of time than intended may lead to the chance of a patient experiencing side effects increasing.

Cysteamine is harsh and can be a difficult medication to take and hold down. If vomiting is experienced within 20 minutes after taking cysteamine, the dose should be taken again. If vomiting happens after a second dose is taken, patients should not take the third dose to compensate. If vomiting is experienced more than 20 minutes after dose, the next dose should be the regularly scheduled dose.

In order to help children younger than two years old take the dose, parents and caregivers may open the capsule and sprinkle the contents into food or formula. However, for those older than two years old, the capsule should be swallowed whole. It may be taken at mealtime, but be aware that high-fat meals may have the effect of decreasing absorption of the medicine.

When cysteamine is taken without food, it should be taken at least 30 minutes before a meal and two hours after one. If directed to take it with food, restrict the amount of food to less than half a cup's worth an hour before or after taking the capsule.

If the patient has difficulty swallowing capsules, the contents may be taken with certain foods or juices. If taken in apple sauce or berry jelly, it should be mixed into about half a cup, all of which should be eaten within a half hour. Care should be taken not to chew the granules in the jelly or applesauce. If taken with juice, grapefruit juice should not be used. Like with food, it needs to be finished within 30 minutes of the first drink and the granules need to be swallowed without chewing. In all cases like this, never keep the mixture for later use.

In some cases, the medication may need to be taken with a gastrostomy tube. If this is needed, the substance used should be half a cup of apple sauce and it should be mixed with the contents of the capsule. If using whole capsules, increase the apple sauce to a minimum of 1 oz. Flush the tube with one cup of fruit juice. The entire process should be completed within 30 minutes. If you've been directed to take additional dietary supplements by a doctor, ensure you comply with this instruction and stick to the guidelines for those supplements.

If taking any medications that include the ingredients bicarbonate or carbonate, cysteamine should be taken at least one hour before or after these medications are taken, rather than at the same time.


Cysteamine is often used in conjunction with other medications and supplements to treat patients who are suffering from the effects of nephropathic cystinosis. However, some medications should not be taken at the same time, and may have adverse effects up to and including making side effects of one or both medications worse.

Make sure that your physician is aware of all prescription and non-prescription medication you are taking for all conditions. If the medications need to be continued, there may be an adjustment of doses or dosing schedules that can minimize the possibility of unfavorable outcomes from drug interactions.

When taking cysteamine, patients need to be aware that there may be interactions with certain types of food and drink. If you have any questions about what should not be consumed when using this medication, ask your doctor.

In general, most foods will be safe, so long as they are not eaten within an hour of the dose, but there are certain exceptions that are considered safe for the purpose of helping children take the medication. Other foods not listed may potentially be approved by your doctor. However, grapefruit juice and alcohol are strictly prohibited when taking cysteamine. Potentially dangerous side effects can result from mixing the medication with these substances.

Certain medical problems may also cause difficulty for those taking cysteamine. Before prescribing this medication, your doctor should know if you have any of these conditions or a history of them. However, if any of these conditions develop after taking the medication, consult with your doctor for further guidance regarding whether or not to continue a cysteamine regimen. These conditions include the following:

  • Blood problems
  • Bone problems
  • Brain disease
  • Depression
  • Head injury
  • Increased pressure
  • Liver disease
  • Seizures
  • Stomach or bowel ulcers or bleeding

In all of these cases, use with caution until you are informed whether or not to continue taking cysteamine, as this drug may make the conditions worse. Do not cease taking the medication unless directed by the prescribing physician.


Patients taking cysteamine should regularly be examined by a doctor to ensure that the medication is working the way that it is intended to. Blood tests, eye exams and examination of skin and bone structure should be incorporated into these visits, as significant unwanted effects are possible.

This is especially important if you are taking high doses of the medication, as it may cause a condition similar to Ehler-Danlos syndrome. If you have any unusual changes to skin or bone structure or if you experience joint problems, immediately inform your physician. The use of cysteamine can cause serious skin reactions, such as blistering, peeling, loosening of the skin, lesions, rashes, sores and ulcers.

Some patients experience chills when they take this medication. Cysteamine is known to be harsh on the stomach and may cause problems of the digestive tract, including internal bleeding. Immediate medical attention should be sought if you experience severe stomach pains, nausea, loss of appetite or vomiting that includes blood that looks like coffee grounds.

Cysteamine may affect the function of the brain and a doctor should be informed if you develop any mental conditions while taking the medication, including seizures, depression and excessive tiredness or dullness of the mind. It may also cause painful eye movement, loss of hearing, blurred or double vision, nausea, ringing in the ears, hearing loss, severe headaches and dizziness or vertigo.

When taking cysteamine, patients should take the time to be aware of how the medication will affect them before they attempt to drive or operate heavy machinery. Failure to do so may result in a dangerous condition of lowered alertness or dizziness that could seriously affect concentration.

Patients should not drink alcohol while using cysteamine, but if alcohol is consumed, medical attention may be necessary. This medication may have an impact on pregnant women and their child, so if you become pregnant or think you may be while using cysteamine, you should inform your doctor immediately.

As with all medications, patients may have an unusual reaction not listed above. If you have had allergic reactions to medications in the past, your healthcare professional should be aware of it prior to prescribing cysteamine. The same is true if you have any allergies, including those to foods, plants or animals. Any potential allergy may affect the decision to prescribe cysteamine and other medications.


Cysteamine should be stored in a closed container at room temperature and kept away from sources of heat, freezing cold, moisture and direct sunlight. Delayed release capsules should be maintained in their original container and not stored in pillboxes or pill sorting devices.

Keep this and all medications out of the reach of children, preferably in a secure location. Do not keep this medication longer than is directed and ensure you dispose of medication that has expired. If you have any questions about the disposal of this medication, ask your doctor or pharmacist for assistance.


While cysteamine is an effective treatment for a rare disease, those who take this medication should be aware that it is a potent medical treatment that may be difficult to take at first. Along with potential side effects, the harsh effects on the stomach and digestive system can cause additional problems.

Patients who take cysteamine need to be aware of the potential risks of developing symptoms similar to Ehler-Danlos syndrome, as this can cause several debilitating conditions. However, the progress of nephropathic cystinosis can be equally debilitating, and cysteamine medications can arrest the progress of this disease significantly. Although there are risks that come with this medication, these risks can be mitigated by not prescribing a large amount of the medication over a long period of time.

While this may make it sound like cysteamine is a risky medication, the risks are actually quite low when it is used as directed. When used properly and with steps taken to minimize digestive problems, this is a very beneficial medication that can be crucial to a combined treatment plan for patients who otherwise may suffer from the failure of the kidneys or other organs. If patients and doctors keep in close communication regarding developments that affect health during the period of time when cysteamine is taken, there is no reason for it to not be part of an effective treatment plan.