"Additionally, someone mentioned DMPS causing kidney pain which is sort of funny because that's one of the prime complaints of DMSA and I've experienced it myself."

It is important to take DMSA on an empty stomach and with at least 8 ounces of water. It is important to stay properly hydrated when using DMSA.

Even if I could get DMPS, in addition to safety concerns the cost would be another reason not to use it. DMSA is expensive enough at around $1 each for a 100 mg capsule. Is a dose of DMPS something like $10? It is easy enough to spend $1,000 on DMSA for a year. I can't imagine spending $10K for DMPS.