From the Schafer Autism Report:
Some pros and cons in three of the most commonly used chelating agents in
DMSA Sodium 2,3 dimercaptopropane- 1 sulfate In the oral form,
approved by the FDA for treating lead poisoning in children as young as 1.
It can remove a wide range of metals, including lead and mercury. Long- term
use can potentially cause bonemarrow suppression or liver damage. It strips
zinc, a beneficial mineral, and supplements may be needed. It can cause
gastrointestinal problems to worsen.
DMPS 2,3 dimercaptosuccinic acid It causes fewer gastrointestinal
problems than other agents and may be more effective at eliminating mercury
than DMSA. It now comes in a cream form, which is easier to use. DMPS is not
FDA-approved although physicians can have it individually compounded for
patients. It has potentially serious side effects and blood and urine need
to be regularly monitored.
TTFD Thiamine tetrahydrofurfuryl disulfide In studies, it had a good
safety record. In a small study of 10 children on the autism spectrum, most
improved clinically. It comes in cream form. It is not approved by the FDA,
although physicians can have it individually compounded for patients. It has
a strong odor described as "skunklike" even in cream form, and has a bad
taste in powdered form making it difficult to give to children who cannot
swallow a capsule.
Source: Autism Research Institute's Defeat Autism Now Project