Information about Cysteamine
Cysteamine is a simple aminothiol molecule that is used to treat nephropathic cystinosis, due to its ability to decrease the markedly elevated and toxic levels of intracellular cystine that occur in this disease and cause its major complications.
Liver safety of Cysteamine
Cysteamine has been associated with serum enzyme elevations when given intravenously in high doses, but it has not been shown to cause clinically apparent acute liver injury.
Mechanism of action of Cysteamine
Cysteamine (sis tee' a meen) is a simple aminothiol molecule which is used to treat nephropathic cystinosis, a rare autosomal recessive disorder characterized by progressive renal tubular dysfunction and growth retardation, and which eventually leads to renal failure and need for dialysis or renal transplantation often within the first decade of life. The underlying defect in cystinosis is a deficiency of an amino acid carrier that transports cystine out of lysosomes. The absence of this transporter causes accumulation of toxic levels of cystine in tissues. Those organs most susceptible to the toxic effects of cystine include the kidney, endocrine tissue, eyes and muscle. Cysteamine readily penetrates cells and is concentrated in lysosomes where it acts by converting intralysosomal cystine to cysteine which is readily transported out of lysosomes. This action leads to a decrease in cellular cystine levels and prevents the renal failure, growth retardation and many of the other chronic complications of nephropathic cystinosis. Cysteamine was approved for the therapy of cystinosis in the United States in 1994. It is now available in several forms including cysteamine bitartrate salt under the commercial name Cystagon (given every 6 hours), as well as a delayed release preparation under the name ProCysBi (given every 12 hours).
Dosage and administration for Cysteamine
The typical maintenance dose is 2.0 grams daily in adults and children above the age of 12, and 1.3 to 1.95 grams/m2 daily in younger children. Cysteamine is usually initiated using a fraction of the maintenance dose, with gradual dose escalation. Both preparations of cysteamine have an unpleasant taste and odor which makes compliance with taking the high doses required to control intracellular cystine levels in cystinosis a frequent problem.
Side effects of Cysteamine
Common side effects include nausea, anorexia, fatigue and diarrhea. Rare, but potentially severe adverse reactions include rash, skin fragility and benign intracranial hypertension. Joint hyperextension, leg pains, osteopenia, fractures and scoliosis also occur in cysteamine treated patients with cystinosis, but are more likely complications of the underlying disease than adverse effects due to cysteamine.
genetic disorder agents
- gaucher disease agents
glucosylceramide synthase inhibitors (substrate restriction therapy)
lysosomal acid lipase deficiency agents
- agalsidase beta, alglucosidase alfa, alpha1-proteinase inhibitor, elosulfase alfa, galsulfase, idursulfase, laronidase, pegademase
Huntington disease agents
Urea Cycle Disorder Agents