Nephropathic Cystinosis

Cystinosis ( 469)
Cystinosis  is rare disorder characterrized by the introsomal accumulation of free cystine in
 body tissue. This results in apperarance of cystine crystals in cornea, conjuctivitis, bone marrow,
lymph nodes, leukocytes and internal organs.

These clinical forms have been identified - an infantile ( nephropathic ) form leading to the Fancomi
syndrome and renal insufficiency in the first decade,  juvenile ( intermediate )  form in which the
renal disease becomes manifest during the second decade, and an adult ( benign ) form
charaterized  by deposition of cystine in the cornea but not in the kidney.

Most common adverse reactions-

Anorexia 31%      diarrhea 16%   fever 22%     lethargy   11%   rash  7%    vomiting 35%

Less common-

CNS-    abnormal thinking,  ataxia, confusion, decreased hearing, depression, dizziness,
             emotional lability, encephalopathy,  hallucinations,  headache,  hyperkinesia,
             jitteriness, nervousness, nghtmares, seizures,  somlonence, tremor.

GI-        abdominal pain, bad breath, constipation, duodenitis, dyspepsia, gastroenteritis,
             GI ulceration, and bleeding, nausea

GU-     interstitial nephritis, renal failure,

Miscellaneous-  abnormal liver function, dehydration, hypertension, leukopenia,  urticaria

Special precautions-
Rash- if a skin rash develops, withhold cysteamine until rash clears.
Cysteamine can be restarted at a lower dose.

CNS effects-  CNS symptoms such as seizures, lethargy, somnolence, depression, and
encepholoapthy have been associated with cysteamine.
If CNS symptoms develop carefully evaluate the patient and adjust the dose as neccesary.

Patients should not engage in hazardous activites until the effects of cysteamine and mental
performance are known.

GI -GI ulceration and bleeding have been reported in patients receiving cysteamine tartarate.
Remiain alert  for signs of ulceration and bleeding  and inform patients/guardians,  about the signs
and symptoms and what steps to take if they occur.

GI symptoms include, nausea, vomiting, and abdominal pain sometimes severe, have been
associated with cysteamine. if these develop therapy may have to be interrupted and dose
adjusted.

Hazardous tasks- cysteamine may cause some people to become drowsy or less alert than they
normally are. Make sure you know how  you or your child ( the patient )  reacts to the medicine
before doing anything that could be dangerous.

Pregnancy- use cysteamime bitartrate during pregnancy only if required.

Lacation- decide whether to discontinue breast feeding or the drug taking into account the
importance of the drug to the mother.

Children - the safety and efficacy of cysteamine  for cystinotic  children have not been
established  

Monitoring- monitor blood counts and liver function studies

Indication-
Nephropathic Cystinosis

Dosage-
Start new patients on1/4 to 1/6 of the maintenance dose of cysteamine. Initiate promptly once the
diagnosis is confirmed ( ie. increased white cell  cystine).

Maintenance dose-
Children up to 12 years of age- is 1.2m2/day  of the free base given in 4 divided doses.

Intact cystine should not be dministered to children younger than approximately 6 years of age,
because of the risk of aspiration.
cystamine capsule may be administered to children younger than approximately 6years of age
by sprinkling the capsule  contents over food.

Patients oldrer than 12 years of age or over 110 Lbs. -
should  receive 2g/day in  4 divided doses.  This dosage  should be reached after 4 to 6 weeks
of incremental dosage increases.

Pharmacology-
Cystamine is cysteine -depleting agents that lowers the cystine content of cells in patients  with
 cystosis, an inherent defect of lysomal transport.

 Cystamine is aminithiol that participates within lysosomes in a thiol -disulfide interchange reaction
 converting cystine into cystine  and cysteine-cystamine mixed disulfide , both of which can exit
 into lyosome in patients with cystinosis

Pregnancy-
Use cysteamime bitartrate during pregnancy only if required.

Lacation-
Decide whether to discontinue breast feeding or the drug taking into account the
importance of the drug to the mother.

Children -
The safety and efficacy of cysteamine  for cystinotic  children have not been
established