DMPS (oral), is actually better than DMSA. It is more tolerated and more effective. And the good aspect is you only have to take it every 6-8 hours, rather than every 4 like DMSA.

I would start taking it as soon as you can, because it may actually help symptoms as it chelates. Usually people expect all these side effects and are often suprised to discover it can actually make them feel better sometimes as they chelate.

Side effects are dependent on how seriously poisoned you are and what dose you're taking. You may need to start very low and work up if things are too much. The main thing is sticking to the frequent dosing to keep things even. That is even more important.

You "May" find some increase in symptoms during the chelatino around, or between rounds, depending on how your body responds. Some people feel better during chelation and worse inbetween on the breaks, some the opposite. At some point, you will have to expect some increase in symptoms, as the mercury has to be shifted out somehow. THe key is not to force yourself to do more than you can even bear. Problem is, some are so poisoned, either way they are in a state, so sometimes you have to tolerate intial big flare ups until enough merury is reduced to where things start going much easier.

I'd say you maybe pleasantly surprised. Many people I know of who are chelating with DMPS wish they could take it permanently because it makes them feel better. So hope that might encourage you a bit.