Cystagon Side Effects/Contraindications


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Side Effects:

Common reported side effects from taking cystagon: nausea, vomiting, reflux, egg like body odor 
  • Vitamin B2 helps to counteract the egg smell
  • Taking cystagon on a full stomach has prevented nausea side effects for some patients 


CYSTAGON® is contraindicated in patients who have developed hypersensitivity to it or to cysteamine or penicillamine.


If a skin rash develops, CYSTAGON® should be withheld until the rash clears. CYSTAGON® may be restarted at a lower dose under close supervision, then slowly titrated to the therapeutic dose. If a severe skin rash develops such as erythema multiforme bullosa or toxic epidermal necrolysis, CYSTAGON® should not be readministered.
CNS symptoms such as seizures, lethargy, somnolence, depression, and encephalopathy have been associated with cysteamine. If CNS symptoms develop, the patient should be carefully evaluated and the dose adjusted as necessary. Neurological complications have been described in some cystinotic patients not on cysteamine treatment. This may be a manifestation of the primary disorder. Patients should not engage in hazardous activities until the effects of CYSTAGON® on mental performance are known.
Gastrointestinal ulceration and bleeding have been reported in patients receiving cysteamine bitartrate. Physicians should remain alert for signs of ulceration and bleeding and should inform patients and/or guardians about the signs and symptoms of serious G.I. toxicity and what steps to take if they occur.
Post marketing reports include one report of interstitial nephritis with early renal failure. A causal relationship between this event and cysteamine bitartrate therapy has not been established.



Gastrointestinal tract symptoms including nausea, vomiting, anorexia and abdominal pain have been associated with cysteamine, sometimes severe. In addition, gastrointestinal ulceration and bleeding have been reported in patients on cysteamine therapy. If these develop, therapy may have to be interrupted and the dose adjusted. A cysteamine dose of 1.95 grams/m2 /day (approximately 80 to 90 mg/kg/day) was associated with an increased number of withdrawals from treatment due to intolerance and an increased incidence of adverse events.
Cysteamine has occasionally been associated with reversible leukopenia and abnormal liver function studies. Therefore, blood counts and liver function studies should be monitored.
There have been reports of benign intracranial hypertension (or pseudotumor cerebri; PTC) and/or papilledema associated with CYSTAGON® treatment that has resolved with the addition of diuretic therapy. PTC may be more common in cystinotic patients because of concurrent medication and renal transplantation. Although a causal relationship of PTC to CYSTAGON® has not been established, physicians should monitor patients receiving CYSTAGON® for this condition. Physicians should instruct patients to report any of the following symptoms: headache, tinnitus, dizziness, nausea, diplopia, blurry vision, loss of vision, pain behind the eye or pain with eye movement. A periodic eye examination is needed to identify this condition early and timely treatment should be provided when it occurs to prevent vision loss.
There have been reports of serious skin lesions in patients treated with high doses of CYSTAGON® or other cysteamine salts that have responded to cysteamine dose reduction. These skin lesions are purplish hemorrhagic lesions over the elbow area on both arms and have been described as molluscoid pseudotumors. Skin striae, bone lesions (that have been described as osteopenia, compression fractures, scoliosis and genu valgum) along with leg pain and joint hyperextension may also be present. One patient with serious skin lesions subsequently died of acute cerebral ischemia with marked vasculopathy. Physicians should routinely monitor the skin and bones of patients receiving CYSTAGON. If similar skin or bone abnormalities appear, the dose of CYSTAGON should be reduced.

**The use of CYSTAGON is contra-indicated during breast-feeding. CYSTAGON should not be used during pregnancy, particularly during the first trimester, unless clearly necessary as it is teratogenic in animals.

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