The Effect of Food on Cysteamine Bitartrate Absorption in Healthy Participants.
OBJECTIVE
Treatment with cysteamine reduces the rate of progression to end-stage kidney disease in cystinosis. Although food is often taken with cysteamine to reduce associated gastrointestinal symptoms, this may alter the bioavailability of cysteamine.


METHODS
This is a prospective, randomized, 3-treatment study to determine the effects of fasting and high-fat/calorie and high-protein meals on cysteamine absorption in healthy adult controls. On 3 separate days, serial plasma cysteamine levels were measured after cysteamine bitartrate 500 mg was ingested while fasting and also 30 minutes after high-fat/calorie and high-protein diets. Gastrointestinal (GI) symptoms were also monitored.


RESULTS
Eight participants (5 men) were enrolled. Cysteamine absorption, as measured by area under the cysteamine concentration-time curve (AUC0-∞ ) while fasted and following high-fat/calorie and high-protein meals, was 3618 ± 372 min·μM, 2799 ± 405 min·μM (P = .04 vs fasted), and 2457 ± 353 min·μM (P = .005), respectively, and the mean Cmax values for participants were 26.3 ± 3.5 μM, 22.4 ± 5.6 μM (P = .16 vs fasted), and 17.2 ± 2.6 μM (P = .036 vs fasted), respectively. Mild GI symptoms were reported in 3 participants.


CONCLUSIONS
Cysteamine absorption may be decreased by 30% when taken with food as compared with the fasting state. Food causes wide variation in tmax and Cmax for cysteamine.
Department of Pediatrics, University of California, San Diego, CA, USARady Children's Hospital, San Diego, CA, USARaptor Pharmaceuticals, Novato, CA, USA.
Ranjan
R
Dohil
Department of Pediatrics, University of California, San Diego, CA, USARady Children's Hospital, San Diego, CA, USARaptor Pharmaceuticals, Novato, CA, USA.
Betty L
BL
Cabrera
Department of Pediatrics, University of California, San Diego, CA, USARady Children's Hospital, San Diego, CA, USARaptor Pharmaceuticals, Novato, CA, USA.
Jon
J
Gangoiti
Department of Pediatrics, University of California, San Diego, CA, USARady Children's Hospital, San Diego, CA, USARaptor Pharmaceuticals, Novato, CA, USA.
Patrice
P
Rioux
Cystagon; cystinosis; high-fat meal; high-protein meal; plasma cysteamine levels