Understanding intestinal cysteamine bitartrate absorption.
OBJECTIVE
To test the hypothesis that a controlled-release preparation of cysteamine, with fewer daily administrations, would improve the quality of life for patients with cystinosis.


METHODS
A specifically designed nasoenteric tube was used to administer cysteamine directly into the stomach, small intestine (SI) and colon and serial plasma cysteamine, serum gastrin and leukocyte cystine levels were measured.


RESULTS
Eight control subjects (mean age 23.2 years) and 6 subjects with cystinosis (mean age 15.2 years) were studied. Cysteamine absorption (maximum concentration and area under the curve of the concentration-time gradient) was greater from the SI than stomach or cecum (P < .01). Leukocyte cystine depletion was greater after delivery of cysteamine into the SI than stomach or cecum; this effect was associated with the plasma cysteamine maximum concentration and area under the curve (P < .001 and < .02, respectively). Gastrin levels were not affected by site of drug delivery and were elevated only in patients with cystinosis with gastrointestinal symptoms.


CONCLUSIONS
The absorption of cysteamine and the effect of this agent on leukocyte cystine depletion are more profound after SI administration. Enteric-coated cysteamine, targeted for SI release, may require fewer daily dosages. Not all patients with cystinosis require acid-suppression therapy.
Dohil
Ranjan
R
Department of Pediatrics, University of California, San Diego, La Jolla, California 92103-8450, USA. rdohil@ucsd.edu
Fidler
Meredith
M
Barshop
Bruce A
BA
Gangoiti
Jon
J
Deutsch
Reena
R
Martin
Michael
M
Schneider
Jerry A
JA
D000293:Adolescent; D000328:Adult; D019540:Area Under Curve; D003543:Cysteamine / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics; D003553:Cystine / Q000032:analysis; D003554:Cystinosis / Q000188:drug therapy* / Q000378:metabolism; D003692:Delayed-Action Preparations; D005260:Female; D005755:Gastrins / Q000097:blood; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology; D007962:Leukocytes / Q000737:chemistry; D008297:Male; D011788:Quality of Life
D003692:Delayed-Action Preparations; D005755:Gastrins; D003553:Cystine; D003543:Cysteamine